Imitrex Nasal Spray

Unless your doctor tells you otherwise, continue your normal diet.

Sumatriptan nasal spray may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• sore or irritated nose
• sore throat
• dry mouth
• unusual taste in the mouth
• nausea
• tiredness
• dizziness
• weakness
• burning or tingling feeling
• sensitivity to loud noises

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• pain, tightness, pressure, or heaviness in the chest, throat, neck, or jaw
• slow or difficult speech
• faintness
• breaking out in a cold sweat
• change in vision
• weakness or numbness of an arm or leg
• fast, pounding, or irregular heartbeat
• bloody diarrhea
• vomiting
• sudden or severe stomach pain
• sudden weight loss
• paleness or blue color of the fingers and toes
• shortness of breath
• swelling of the eyes, face, lips, tongue, or throat
• difficulty breathing or swallowing
• rash
• hives
• hoarseness
• pain, burning, or tingling in the hands or feet
• seizures

Sumatriptan nasal spray may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Serious cardiac events, including some that have been fatal, have occurred following the use of IMITREX Injection or Tablets. These events are extremely rare and most have been reported in patients with risk factors predictive of CAD. Events reported have included coronary artery vasospasm, transient myocardial ischemia, myocardial infarction, ventricular tachycardia, and ventricular fibrillation (see CONTRAINDICATIONS, WARNINGS, and PRECAUTIONS).

Significant hypertensive episodes, including hypertensive crises, have been reported on rare occasions in patients with or without a history of hypertension (see WARNINGS).

Incidence in Controlled Clinical Trials: Among 3,653 patients treated with IMITREX Nasal Spray (sumatriptan nasal spray) in active- and placebo-controlled clinical trials, less than 0.4% of patients withdrew for reasons related to adverse events. Table 2 lists adverse events that occurred in worldwide placebo-controlled clinical trials in 3,419 migraineurs. The events cited reflect experience gained under closely monitored conditions of clinical trials in a highly selected patient population. In actual clinical practice or in other clinical trials, these frequency estimates may not apply, as the conditions of use, reporting behavior, and the kinds of patients treated may differ.

Only events that occurred at a frequency of 1% or more in the IMITREX Nasal Spray (sumatriptan nasal spray) 20-mg treatment group and were more frequent in that group than in the placebo group are included in Table 2.

Table 2. Treatment-Emergent Adverse Events Reported by at Least 1% of Patients in Controlled Migraine Trials

Adverse Event Type	Percent of Patients Reporting
	Placebo (n = 704)	IMITREX5 mg (n = 496)	IMITREX10 mg (n = 1,007)	IMITREX20 mg (n = 1,212)
Atypical sensations Burning sensation	0.1%	0.4%	0.6%	1.4%
Ear, nose, and throat Disorder/discomfort of nasal cavity/sinuses	2.4%	2.8%	2.5%	3.8%
Throat discomfort	0.9%	0.8%	1.8%	2.4%
Gastrointestinal Nausea and/or vomiting	11.3%	12.2%	11.0%	13.5%
Neurological Bad/unusual taste	1.7%	13.5%	19.3%	24.5%
Dizziness/vertigo	0.9%	1.0%	1.7%	1.4%

Phonophobia also occurred in more than 1% of patients but was more frequent on placebo.

IMITREX Nasal Spray (sumatriptan nasal spray) is generally well tolerated. Across all doses, most adverse reactions were mild and transient and did not lead to long-lasting effects. The incidence of adverse events in controlled clinical trials was not affected by gender, weight, or age of the patients; use of prophylactic medications; or presence of aura. There were insufficient data to assess the impact of race on the incidence of adverse events.

Other Events Observed in Association With the Administration of IMITREX Nasal Spray

In the paragraphs that follow, the frequencies of less commonly reported adverse clinical events are presented. Because the reports include events observed in open and uncontrolled studies, the role of IMITREX Nasal Spray (sumatriptan nasal spray) in their causation cannot be reliably determined. Furthermore, variability associated with adverse event reporting, the terminology used to describe adverse events, etc., limit the value of the quantitative frequency estimates provided. Event frequencies are calculated as the number of patients who used IMITREX Nasal Spray (sumatriptan nasal spray) (5, 10, or 20 mg in controlled and uncontrolled trials) and reported an event divided by the total number of patients (N = 3,711) exposed to IMITREX Nasal Spray (sumatriptan nasal spray) . All reported events are included except those already listed in the previous table, those too general to be informative, and those not reasonably associated with the use of the drug. Events are further classified within body system categories and enumerated in order of decreasing frequency using the following definitions: infrequent adverse events are those occurring in 1/100 to 1/1,000 patients and rare adverse events are those occurring in fewer than 1/1,000 patients.

Atypical Sensations: Infrequent were tingling, warm/hot sensation, numbness, pressure sensation, feeling strange, feeling of heaviness, feeling of tightness, paresthesia, cold sensation, and tight feeling in head. Rare were dysesthesia and prickling sensation.

Cardiovascular: Infrequent were flushing and hypertension (see WARNINGS), palpitations, tachycardia, changes in ECG, and arrhythmia (see WARNINGS and PRECAUTIONS). Rare were abdominal aortic aneurysm, hypotension, bradycardia, pallor, and phlebitis.

Chest Symptoms: Infrequent were chest tightness, chest discomfort, and chest pressure/heaviness (see PRECAUTIONS: General).

Ear, Nose, and Throat: Infrequent were disturbance of hearing and ear infection. Rare were otalgia and Meniere disease.

Endocrine and Metabolic: Infrequent was thirst. Rare were galactorrhea, hypothyroidism, and weight loss.

Eye: Infrequent were irritation of eyes and visual disturbance.

Gastrointestinal: Infrequent were abdominal discomfort, diarrhea, dysphagia, and gastroesophageal reflux. Rare were constipation, flatulence/eructation, hematemesis, intestinal obstruction, melena, gastroenteritis, colitis, hemorrhage of gastrointestinal tract, and pancreatitis.

Mouth and Teeth: Infrequent was disorder of mouth and tongue (e.g., burning of tongue, numbness of tongue, dry mouth).

Musculoskeletal: Infrequent were neck pain/stiffness, backache, weakness, joint symptoms, arthritis, and myalgia. Rare were muscle cramps, tetany, intervertebral disc disorder, and muscle stiffness.

Neurological: Infrequent were drowsiness/sedation, anxiety, sleep disturbances, tremors, syncope, shivers, chills, depression, agitation, sensation of lightness, and mental confusion. Rare were difficulty concentrating, hunger, lacrimation, memory disturbances, monoplegia/diplegia, apathy, disturbance of smell, disturbance of emotions, dysarthria, facial pain, intoxication, stress, decreased appetite, difficulty coordinating, euphoria, and neoplasm of pituitary.

Respiratory: Infrequent were dyspnea and lower respiratory tract infection. Rare was asthma.

Skin: Infrequent were rash/skin eruption, pruritus, and erythema. Rare were herpes, swelling of face, sweating, and peeling of skin.

Urogenital: Infrequent were dysuria, disorder of breasts, and dysmenorrhea. Rare were endometriosis and increased urination.

Miscellaneous: Infrequent were cough, edema, and fever. Rare were hypersensitivity, swelling of extremities, voice disturbances, difficulty in walking, and lymphadenopathy.

Other Events Observed in the Clinical Development of IMITREX

The following adverse events occurred in clinical trials with IMITREX Injection and IMITREX Tablets. Because the reports include events observed in open and uncontrolled studies, the role of

IMITREX in their causation cannot be reliably determined. All reported events are included except those already listed, those too general to be informative, and those not reasonably associated with the use of the drug.

Breasts: Breast swelling; cysts, lumps, and masses of breasts; nipple discharge; primary malignant breast neoplasm; and tenderness.

Cardiovascular:Abnormal pulse, angina, atherosclerosis, cerebral ischemia, cerebrovascular lesion, heart block, peripheral cyanosis, pulsating sensations, Raynaud syndrome, thrombosis, transient myocardial ischemia, various transient ECG changes (nonspecific ST or T wave changes, prolongation of PR or QTc intervals, sinus arrhythmia, nonsustained ventricular premature beats, isolated junctional ectopic beats, atrial ectopic beats, delayed activation of the right ventricle), and vasodilation.

Ear, Nose, and Throat: Allergic rhinitis; ear, nose, and throat hemorrhage; external otitis; feeling of fullness in the ear(s); hearing disturbances; hearing loss; nasal inflammation; sensitivity to noise; sinusitis; tinnitus; and upper respiratory inflammation.

Endocrine and Metabolic:Dehydration; endocrine cysts, lumps, and masses; elevated thyrotropin stimulating hormone (TSH) levels; fluid disturbances; hyperglycemia; hypoglycemia; polydipsia; and weight gain.

Eye: Accommodation disorders, blindness and low vision, conjunctivitis, disorders of sclera, external ocular muscle disorders, eye edema and swelling, eye itching, eye hemorrhage, eye pain, keratitis, mydriasis, and vision alterations.

Gastrointestinal: Abdominal distention, dental pain, disturbances of liver function tests, dyspeptic symptoms, feelings of gastrointestinal pressure, gallstones, gastric symptoms, gastritis, gastrointestinal pain, hypersalivation, hyposalivation, oral itching and irritation, peptic ulcer, retching, salivary gland swelling, and swallowing disorders.

Hematological Disorders:Anemia.

Injection Site Reaction

Miscellaneous: Contusions, fluid retention, hematoma, hypersensitivity to various agents, jaw discomfort, miscellaneous laboratory abnormalities, overdose, “serotonin agonist effect,” and speech disturbance.

Musculoskeletal: Acquired musculoskeletal deformity, arthralgia and articular rheumatitis, muscle atrophy, muscle tiredness, musculoskeletal inflammation, need to flex calf muscles, rigidity, tightness, and various joint disturbances (pain, stiffness, swelling, ache).

Neurological: Aggressiveness, bradylogia, cluster headache, convulsions, detachment, disturbances of taste, drug abuse, dystonia, facial paralysis, globus hystericus, hallucinations, headache, heat sensitivity, hyperesthesia, hysteria, increased alertness, malaise/fatigue, migraine, motor dysfunction, myoclonia, neuralgia, neurotic disorders, paralysis, personality change, phobia, photophobia, psychomotor disorders, radiculopathy, raised intracranial pressure, relaxation, stinging sensations, transient hemiplegia, simultaneous hot and cold sensations, suicide, tickling sensations, twitching, and yawning.

Pain and Other Pressure Sensations:Chest pain, neck tightness/pressure, throat/jaw pain/tightness/pressure, and pain (location specified).

Respiratory:Breathing disorders, bronchitis, diseases of the lower respiratory tract, hiccoughs, and influenza.

Skin: Dry/scaly skin, eczema, seborrheic dermatitis, skin nodules, skin tenderness, tightness of skin, and wrinkling of skin.

Urogenital:Abortion, abnormal menstrual cycle, bladder inflammation, hematuria, inflammation of fallopian tubes, intermenstrual bleeding, menstruation symptoms, micturition disorders, renal calculus, urethritis, urinary frequency, and urinary infections.

Postmarketing Experience (Reports for Subcutaneous or Oral Sumatriptan)

The following section enumerates potentially important adverse events that have occurred in clinical practice and that have been reported spontaneously to various surveillance systems. The events enumerated represent reports arising from both domestic and nondomestic use of oral or subcutaneous dosage forms of sumatriptan. The events enumerated include all except those already listed in the ADVERSE REACTIONS section above or those too general to be informative. Because the reports cite events reported spontaneously from worldwide postmarketing experience, frequency of events and the role of sumatriptan in their causation cannot be reliably determined. It is assumed, however, that systemic reactions following sumatriptan use are likely to be similar regardless of route of administration.

Blood:Hemolytic anemia, pancytopenia, thrombocytopenia.

Cardiovascular:Atrial fibrillation, cardiomyopathy, colonic ischemia (see WARNINGS), Prinzmetal variant angina, pulmonary embolism, shock, thrombophlebitis.

Ear, Nose, and Throat:Deafness.

Eye: Ischemic optic neuropathy, retinal artery occlusion, retinal vein thrombosis, loss of vision.

Gastrointestinal: Ischemic colitis with rectal bleeding (see WARNINGS), xerostomia.

Hepatic: Elevated liver function tests.

Neurological:Central nervous system vasculitis, cerebrovascular accident, dysphasia, serotonin syndrome, subarachnoid hemorrhage.

Non-Site Specific: Angioneurotic edema, cyanosis, death (see WARNINGS), temporal arteritis.

Psychiatry: Panic disorder.

Respiratory: Bronchospasm in patients with and without a history of asthma.

Skin: Exacerbation of sunburn, hypersensitivity reactions (allergic vasculitis, erythema, pruritus, rash, shortness of breath, urticaria; in addition, severe anaphylaxis/anaphylactoid reactions have been reported [see WARNINGS]), photosensitivity.

Urogenital: Acute renal failure.

Drug Abuse And Dependence

One clinical study with IMITREX (sumatriptan succinate) Injection enrolling 12 patients with a history of substance abuse failed to induce subjective behavior and/or physiologic response ordinarily associated with drugs that have an established potential for abuse.

IMITREX Nasal Spray (sumatriptan nasal spray) should only be used where a clear diagnosis of migraine headache has been established.

Risk of Myocardial Ischemia and/or Infarction and Other Adverse Cardiac Events: Sumatriptan should not be given to patients with documented ischemic or vasospastic coronary artery disease (CAD) (see CONTRAINDICATIONS). It is strongly recommended that sumatriptan not be given to patients in whom unrecognized CAD is predicted by the presence of risk factors (e.g., hypertension, hypercholesterolemia, smoker, obesity, diabetes, strong family history of CAD, female with surgical or physiological menopause, or male over 40 years of age) unless a cardiovascular evaluation provides satisfactory clinical evidence that the patient is reasonably free of coronary artery and ischemic myocardial disease or other significant underlying cardiovascular disease. The sensitivity of cardiac diagnostic procedures to detect cardiovascular disease or predisposition to coronary artery vasospasm is modest, at best. If, during the cardiovascular evaluation, the patient's medical history or electrocardiographic investigations reveal findings indicative of, or consistent with, coronary artery vasospasm or myocardial ischemia, sumatriptan should not be administered (see CONTRAINDICATIONS).

For patients with risk factors predictive of CAD, who are determined to have a satisfactory cardiovascular evaluation, it is strongly recommended that administration of the first dose of sumatriptan nasal spray take place in the setting of a physician's office or similar medically staffed and equipped facility unless the patient has previously received sumatriptan. Because cardiac ischemia can occur in the absence of clinical symptoms, consideration should be given to obtaining on the first occasion of use an electrocardiogram (ECG) during the interval immediately following IMITREX Nasal Spray (sumatriptan nasal spray) , in these patients with risk factors.

It is recommended that patients who are intermittent long-term users of sumatriptan and who have or acquire risk factors predictive of CAD, as described above, undergo periodic interval cardiovascular evaluation as they continue to use sumatriptan.

The systematic approach described above is intended to reduce the likelihood that patients with unrecognized cardiovascular disease will be inadvertently exposed to sumatriptan.

Drug-Associated Cardiac Events and Fatalities

Serious adverse cardiac events, including acute myocardial infarction, life-threatening disturbances of cardiac rhythm, and death have been reported within a few hours following the administration of IMITREX® (sumatriptan succinate) Injection or IMITREX® (sumatriptan succinate) Tablets. Considering the extent of use of sumatriptan in patients with migraine, the incidence of these events is extremely low.

The fact that sumatriptan can cause coronary vasospasm, that some of these events have occurred in patients with no prior cardiac disease history and with documented absence of CAD, and the close proximity of the events to sumatriptan use support the conclusion that some of these cases were caused by the drug. In many cases, however, where there has been known underlying coronary artery disease, the relationship is uncertain.

Premarketing Experience With Sumatriptan: Among approximately 4,000 patients with migraine who participated in premarketing controlled and uncontrolled clinical trials of sumatriptan nasal spray, 1 patient experienced an asymptomatic subendocardial infarction possibly subsequent to a coronary vasospastic event.

Of 6,348 patients with migraine who participated in premarketing controlled and uncontrolled clinical trials of oral sumatriptan, 2 experienced clinical adverse events shortly after receiving oral sumatriptan that may have reflected coronary vasospasm. Neither of these adverse events was associated with a serious clinical outcome.

Among the more than 1,900 patients with migraine who participated in premarketing controlled clinical trials of subcutaneous sumatriptan, there were 8 patients who sustained clinical events during or shortly after receiving sumatriptan that may have reflected coronary artery vasospasm. Six of these 8 patients had ECG changes consistent with transient ischemia, but without accompanying clinical symptoms or signs. Of these 8 patients, 4 had either findings suggestive of CAD or risk factors predictive of CAD prior to study enrollment.

Postmarketing Experience With Sumatriptan: Serious cardiovascular events, some resulting in death, have been reported in association with the use of IMITREX Injection or IMITREX Tablets. The uncontrolled nature of postmarketing surveillance, however, makes it impossible to determine definitively the proportion of the reported cases that were actually caused by sumatriptan or to reliably assess causation in individual cases. On clinical grounds, the longer the latency between the administration of IMITREX and the onset of the clinical event, the less likely the association is to be causative. Accordingly, interest has focused on events beginning within 1 hour of the administration of IMITREX.

Cardiac events that have been observed to have onset within 1 hour of sumatriptan administration include: coronary artery vasospasm, transient ischemia, myocardial infarction, ventricular tachycardia and ventricular fibrillation, cardiac arrest, and death.

Some of these events occurred in patients who had no findings of CAD and appear to represent consequences of coronary artery vasospasm. However, among domestic reports of serious cardiac events within 1 hour of sumatriptan administration, almost all of the patients had risk factors predictive of CAD and the presence of significant underlying CAD was established in most cases (see CONTRAINDICATIONS).

Drug-Associated Cerebrovascular Events and Fatalities

Cerebral hemorrhage, subarachnoid hemorrhage, stroke, and other cerebrovascular events have been reported in patients treated with oral or subcutaneous sumatriptan, and some have resulted in fatalities. The relationship of sumatriptan to these events is uncertain. In a number of cases, it appears possible that the cerebrovascular events were primary, sumatriptan having been administered in the incorrect belief that the symptoms experienced were a consequence of migraine when they were not. As with other acute migraine therapies, before treating headaches in patients not previously diagnosed as migraineurs, and in migraineurs who present with atypical symptoms, care should be taken to exclude other potentially serious neurological conditions. It should also be noted that patients with migraine may be at increased risk of certain cerebrovascular events (e.g., cerebrovascular accident, transient ischemic attack).

Other Vasospasm-Related Events

Sumatriptan may cause vasospastic reactions other than coronary artery vasospasm. Both peripheral vascular ischemia and colonic ischemia with abdominal pain and bloody diarrhea have been reported. Very rare reports of transient and permanent blindness and significant partial vision loss have been reported with the use of sumatriptan. Visual disorders may also be part of a migraine attack.

Serotonin Syndrome

The development of a potentially life-threatening serotonin syndrome may occur with triptans, including treatment with IMITREX, particularly during combined use with selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs). If concomitant treatment with sumatriptan and an SSRI (e.g., fluoxetine, paroxetine, sertraline, fluvoxamine, citalopram, escitalopram) or SNRI (e.g., venlafaxine, duloxetine) is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases. Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, coma), autonomic instability (e.g., tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination), and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).

Increase in Blood Pressure

Significant elevation in blood pressure, including hypertensive crisis, has been reported on rare occasions in patients with and without a history of hypertension. Sumatriptan is contraindicated in patients with uncontrolled hypertension (see CONTRAINDICATIONS). Sumatriptan should be administered with caution to patients with controlled hypertension as transient increases in blood pressure and peripheral vascular resistance have been observed in a small proportion of patients.

Local Irritation

Of the 3,378 patients using the nasal spray (5-, 10-, or 20-mg doses) on 1 or 2 occasions in controlled clinical studies, approximately 5% noted irritation in the nose and throat. Irritative symptoms such as burning, numbness, paresthesia, discharge, and pain or soreness were noted to be severe in about 1% of patients treated. The symptoms were transient and in approximately 60% of the cases, the symptoms resolved in less than 2 hours. Limited examinations of the nose and throat did not reveal any clinically noticeable injury in these patients.

The consequences of extended and repeated use of IMITREX Nasal Spray (sumatriptan nasal spray) on the nasal and/or respiratory mucosa have not been systematically evaluated in patients. No increase in the incidence of local irritation was observed in patients using IMITREX Nasal Spray (sumatriptan nasal spray) repeatedly for up to 1 year.

In inhalation studies in rats dosed daily for up to 1 month at exposures as low as one half the maximum daily human exposure (based on dose per surface area of nasal cavity), epithelial hyperplasia (with and without keratinization) and squamous metaplasia were observed in the larynx at all doses tested. These changes were partially reversible after a 2-week drug-free period. When dogs were dosed daily with various formulations by intranasal instillation for up to 13 weeks at exposures of 2 to 4 times the maximum daily human exposure (based on dose per surface area of nasal cavity), respiratory and nasal mucosa exhibited evidence of epithelial hyperplasia, focal squamous metaplasia, granulomata, bronchitis, and fibrosing alveolitis. A no-effect dose was not established. The changes observed in both species are not considered to be signs of either preneoplastic or neoplastic transformation.

Local effects on nasal and respiratory tissues after chronic intranasal dosing in animals have not been studied.

Concomitant Drug Use

In patients taking MAO-A inhibitors, sumatriptan plasma levels attained after treatment with recommended doses are 2-fold (following subcutaneous administration) to 7-fold (following oral administration) higher than those obtained under other conditions. Accordingly, the coadministration of IMITREX Nasal Spray (sumatriptan nasal spray) and an MAO-A inhibitor is contraindicated (see CLINICAL PHARMACOLOGY and CONTRAINDICATIONS).

Hypersensitivity

Hypersensitivity (anaphylaxis/anaphylactoid) reactions have occurred on rare occasions in patients receiving sumatriptan. Such reactions can be life threatening or fatal. In general, hypersensitivity reactions to drugs are more likely to occur in individuals with a history of sensitivity to multiple allergens (see CONTRAINDICATIONS).

Mechanism of Action

Sumatriptan is an agonist for a vascular 5-hydroxytryptamine1receptor subtype (probably a member of the 5-HT1D family) having only a weak affinity for 5-HT1A, 5-HT5A, and 5-HT7 receptors and no significant affinity (as measured using standard radioligand binding assays) or pharmacological activity at 5-HT2, 5-HT3, or 5-HT4 receptor subtypes or at alpha1-, alpha2-, or beta-adrenergic; dopamine1; dopamine2; muscarinic; or benzodiazepine receptors.

The vascular 5-HT1 receptor subtype that sumatriptan activates is present on cranial arteries in both dog and primate, on the human basilar artery, and in the vasculature of human dura mater and mediates vasoconstriction. This action in humans correlates with the relief of migraine headache. In addition to causing vasoconstriction, experimental data from animal studies show that sumatriptan also activates 5-HT1 receptors on peripheral terminals of the trigeminal nerve innervating cranial blood vessels. Such an action may contribute to the antimigrainous effect of sumatriptan in humans.

In the anesthetized dog, sumatriptan selectively reduces the carotid arterial blood flow with little or no effect on arterial blood pressure or total peripheral resistance. In the cat, sumatriptan selectively constricts the carotid arteriovenous anastomoses while having little effect on blood flow or resistance in cerebral or extracerebral tissues.

Pharmacokinetics

In a study of 20 female volunteers, the mean maximum concentration following a 5- and 20-mg intranasal dose was 5 and 16 ng/mL, respectively. The mean Cmax following a 6-mg subcutaneous injection is 71 ng/mL (range, 49 to 110 ng/mL). The mean Cmax is 18 ng/mL (range, 7 to 47 ng/mL) following oral dosing with 25 mg and 51 ng/mL (range, 28 to 100 ng/mL) following oral dosing with 100 mg of sumatriptan. In a study of 24 male volunteers, the bioavailability relative to subcutaneous injection was low, approximately 17%, primarily due to presystemic metabolism and partly due to incomplete absorption.

Protein binding, determined by equilibrium dialysis over the concentration range of 10 to 1,000 ng/mL, is low, approximately 14% to 21%. The effect of sumatriptan on the protein binding of other drugs has not been evaluated, but would be expected to be minor, given the low rate of protein binding. The mean volume of distribution after subcutaneous dosing is 2.7 L/kg and the total plasma clearance is approximately 1,200 mL/min.

The elimination half-life of sumatriptan administered as a nasal spray is approximately 2 hours, similar to the half-life seen after subcutaneous injection. Only 3% of the dose is excreted in the urine as unchanged sumatriptan; 42% of the dose is excreted as the major metabolite, the indole acetic acid analogue of sumatriptan.

Clinical and pharmacokinetic data indicate that administration of two 5-mg doses, 1 dose in each nostril, is equivalent to administration of a single 10-mg dose in 1 nostril.

Special Populations

Renal Impairment: The effect of renal impairment on the pharmacokinetics of sumatriptan has not been examined, but little clinical effect would be expected as sumatriptan is largely metabolized to an inactive substance.

Hepatic Impairment: The effect of hepatic disease on the pharmacokinetics of subcutaneously and orally administered sumatriptan has been evaluated, but the intranasal dosage form has not been studied in hepatic impairment. There were no statistically significant differences in the pharmacokinetics of subcutaneously administered sumatriptan in hepatically impaired patients compared to healthy controls. However, the liver plays an important role in the presystemic clearance of orally administered sumatriptan. In 1 small study involving oral sumatriptan in hepatically impaired patients (N = 8) matched for sex, age, and weight with healthy subjects, the hepatically impaired patients had an approximately 70% increase in AUC and Cmax and a Tmax 40 minutes earlier compared to the healthy subjects. The bioavailability of nasally absorbed sumatriptan following intranasal administration, which would not undergo first-pass metabolism, should not be altered in hepatically impaired patients. The bioavailability of the swallowed portion of the intranasal sumatriptan dose has not been determined, but would be increased in these patients. The swallowed intranasal dose is small, however, compared to the usual oral dose, so that its impact should be minimal.

Age: The pharmacokinetics of oral sumatriptan in the elderly (mean age, 72 years; 2 males and 4 females) and in patients with migraine (mean age, 38 years; 25 males and 155 females) were similar to that in healthy male subjects (mean age, 30 years). Intranasal sumatriptan has not been evaluated for age differences (see PRECAUTIONS: Geriatric Use).

Race: The systemic clearance and Cmax of sumatriptan were similar in black (n = 34) and Caucasian (n = 38) healthy male subjects. Intranasal sumatriptan has not been evaluated for race differences.

Drug Interactions

Monoamine Oxidase Inhibitors: Treatment with monoamine oxidase inhibitors (MAOIs) generally leads to an increase of sumatriptan plasma levels (see CONTRAINDICATIONS and PRECAUTIONS).

MAOI interaction studies have not been performed with intranasal sumatriptan. Due to gut and hepatic metabolic first-pass effects, the increase of systemic exposure after coadministration of an MAO-A inhibitor with oral sumatriptan is greater than after coadministration of the MAOI with subcutaneous sumatriptan. The effects of an MAOI on systemic exposure after intranasal sumatriptan would be expected to be greater than the effect after subcutaneous sumatriptan but smaller than the effect after oral sumatriptan because only swallowed drug would be subject to first-pass effects.

In a study of 14 healthy females, pretreatment with an MAO-A inhibitor decreased the clearance of subcutaneous sumatriptan. Under the conditions of this experiment, the result was a 2-fold increase in the area under the sumatriptan plasma concentration x time curve (AUC), corresponding to a 40% increase in elimination half-life. This interaction was not evident with an MAO-B inhibitor.

A small study evaluating the effect of pretreatment with an MAO-A inhibitor on the bioavailability from a 25-mg oral sumatriptan tablet resulted in an approximately 7-fold increase in systemic exposure.

Xylometazoline: An in vivo drug interaction study indicated that 3 drops of xylometazoline (0.1% w/v), a decongestant, administered 15 minutes prior to a 20-mg nasal dose of sumatriptan did not alter the pharmacokinetics of sumatriptan.

Clinical Trials

The efficacy of IMITREX Nasal Spray (sumatriptan nasal spray) in the acute treatment of migraine headaches was demonstrated in 8, randomized, double-blind, placebo-controlled studies, of which 5 used the recommended dosing regimen and used the marketed formulation. Patients enrolled in these 5 studies were predominately female (86%) and Caucasian (95%), with a mean age of 41 (range of 18 to 65). Patients were instructed to treat a moderate to severe headache. Headache response, defined as a reduction in headache severity from moderate or severe pain to mild or no pain, was assessed up to 2 hours after dosing. Associated symptoms such as nausea, photophobia, and phonophobia were also assessed. Maintenance of response was assessed for up to 24 hours postdose. A second dose of IMITREX Nasal Spray (sumatriptan nasal spray) or other medication was allowed 2 to 24 hours after the initial treatment for recurrent headache. The frequency and time to use of these additional treatments were also determined. In all studies, doses of 10 and 20 mg were compared to placebo in the treatment of 1 to 3 migraine attacks. Patients received doses as a single spray into 1 nostril. In 2 studies, a 5-mg dose was also evaluated.

In all 5 trials utilizing the market formulation and recommended dosage regimen, the percentage of patients achieving headache response 2 hours after treatment was significantly greater among patients receiving IMITREX Nasal Spray (sumatriptan nasal spray) at all doses (with one exception) compared to those who received placebo. In 4 of the 5 studies, there was a statistically significant greater percentage of patients with headache response at 2 hours in the 20-mg group when compared to the lower dose groups (5 and 10 mg). There were no statistically significant differences between the 5- and 10-mg dose groups in any study. The results from the 5 controlled clinical trials are summarized in Table 1. Note that, in general, comparisons of results obtained in studies conducted under different conditions by different investigators with different samples of patients are ordinarily unreliable for purposes of quantitative comparison.

Table 1. Percentage of Patients With Headache Response (No or Mild Pain) 2 Hours Following Treatment

	Placebo	IMITREX Nasal Spray 5 mg	IMITREX Nasal Spray 10 mg	IMITREX Nasal Spray 20 mg
Study 1	25% (n = 63)	49%* (n = 121)	46%* (n = 112)	64%*†‡ (n = 118)
Study 2	25% (n = 138)	Not applicable	44%* (n = 273)	55%*† (n = 277)
Study 3	35% (n = 100)	Not applicable	54%* (n = 106)	63%* (n = 202)
Study 4	29% (n = 112)	Not applicable	43% (n = 106)	62%*† (n = 215)
Study 5§	36% (n = 198)	45%* (n = 296)	53%* (n = 291)	60% (n = 286)‡
*p < 0.05 in comparison with placebo. †p < 0.05 in comparison with 10 mg. ‡p < 0.05 in comparison with 5 mg. §Data are for attack 1 only of multiattack study for comparison

The estimated probability of achieving an initial headache response over the 2 hours following treatment is depicted in Figure 1.

Figure 1. Estimated Probability of Achieving Initial Headache Response Within 120 Minutes*

* The figure shows the probability over time of obtaining headache response (no or mild pain) following treatment with intranasal sumatriptan. The averages displayed are based on pooled data from the 5 clinical controlled trials providing evidence of efficacy. Kaplan-Meier plot with patients not achieving response within 120 minutes censored to 120 minutes.

For patients with migraine-associated nausea, photophobia, and phonophobia at baseline, there was a lower incidence of these symptoms at 2 hours following administration of IMITREX Nasal Spray (sumatriptan nasal spray) compared to placebo.

Two to 24 hours following the initial dose of study treatment, patients were allowed to use additional treatment for pain relief in the form of a second dose of study treatment or other medication. The estimated probability of patients taking a second dose or other medication for migraine over the 24 hours following the initial dose of study treatment is summarized in Figure 2.

Figure 2. The Estimated Probability of Patients Taking a Second Dose or Other Medication for Migraine Over the 24 Hours Following the Initial Dose of Study Treatment*

* Kaplan-Meier plot based on data obtained in the 3 clinical controlled trials providing evidence of efficacy with patients not using additional treatments censored to 24 hours. Plot also includes patients who had no response to the initial dose. No remedication was allowed within 2 hours postdose.

There is evidence that doses above 20 mg do not provide a greater effect than 20 mg. There was no evidence to suggest that treatment with sumatriptan was associated with an increase in the severity of recurrent headaches. The efficacy of IMITREX Nasal Spray (sumatriptan nasal spray) was unaffected by presence of aura; duration of headache prior to treatment; gender, age, or weight of the patient; or concomitant use of common migraine prophylactic drugs (e.g., beta-blockers, calcium channel blockers, tricyclic antidepressants). There were insufficient data to assess the impact of race on efficacy.

Animal Toxicology

Corneal Opacities: Dogs receiving oral sumatriptan developed corneal opacities and defects in the corneal epithelium. Corneal opacities were seen at the lowest dosage tested, 2 mg/kg/day, and were present after 1 month of treatment. Defects in the corneal epithelium were noted in a 60-week study. Earlier examinations for these toxicities were not conducted and no-effect doses were not established; however, the relative exposure at the lowest dose tested was approximately 5 times the human exposure after a 100-mg oral dose or 3 times the human exposure after a 6-mg subcutaneous dose or 22 times the human exposure after a single 20-mg intranasal dose. There is evidence of alterations in corneal appearance on the first day of intranasal dosing to dogs. Changes were noted at the lowest dose tested, which was approximately 2 times the maximum single human intranasal dose of 20 mg on a mg/m2 basis.

You should not use this medication if you are allergic to sumatriptan, if you have any history of heart disease, or if you have coronary heart disease, angina, blood circulation problems, lack of blood supply to the heart, uncontrolled high blood pressure, severe liver disease, ischemic bowel disease, a history of a heart attack or stroke, or if your headache seems to be different from your usual migraine headaches.

Do not use sumatriptan within 24 hours before or after using another migraine headache medicine, including sumatriptan injection, almotriptan (Axert), eletriptan (Relpax), frovatriptan (Frova), rizatriptan (Maxalt), naratriptan (Amerge), zolmitriptan (Zomig), or ergot medicine such as dihydroergotamine (D.H.E. 45, Migranal), ergotamine (Ergomar, Cafergot, Migergot), dihydroergotamine (D.H.E. 45, Migranal), or methylergonovine (Methergine).

Do not use sumatriptan if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days.

Before using sumatriptan, tell your doctor if you have liver or kidney disease, seizures, high blood pressure, a heart rhythm disorder, or coronary heart disease (or risk factors such as diabetes, menopause, smoking, being overweight, having high cholesterol, having a family history of coronary artery disease, being older than 40 and a man, or being a woman who has had a hysterectomy).

Also tell your doctor if you are taking an antidepressant such as citalopram (Celexa), desvenlafaxine (Pristiq), duloxetine (Cymbalta), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), paroxetine (Paxil), sertraline (Zoloft), or venlafaxine (Effexor).

Sumatriptan will only treat a headache that has already begun. It will not prevent headaches or reduce the number of attacks.

After taking a sumatriptan tablet, you must wait two (2) hours before taking a second tablet. Do not take more than 200 mg of sumatriptan tablets in 24 hours.

After using sumatriptan nasal spray, you must wait two (2) hours before using a second spray. Do not use more than 40 mg of sumatriptan nasal spray in 24 hours.

Imitrex Nasal Spray is contraindicated in patients with:

• Ischemic coronary artery disease (CAD) (angina pectoris, history of myocardial infarction, or documented silent ischemia) or coronary artery vasospasm, including Prinzmetal’s angina [see Warnings and Precautions (5.1)] • Wolff-Parkinson-White syndrome or arrhythmias associated with other cardiac accessory conduction pathway disorders [see Warnings and Precautions (5.2)] • History of stroke, transient ischemic attack (TIA), or history of hemiplegic or basilar migraine because these patients are at a higher risk of stroke [see Warnings and Precautions (5.4)] • Peripheral vascular disease [see Warnings and Precautions (5.5)] • Ischemic bowel disease [see Warnings and Precautions (5.5)] • Uncontrolled hypertension [see Warnings and Precautions (5.8)] • Recent use (i.e., within 24 hours) of ergotamine-containing medication, ergot-type medication (such as dihydroergotamine or methysergide), or another 5-hydroxytryptamine1 (5-HT1) agonist [see Drug Interactions (7.1, 7.3)] • Concurrent administration of a monoamine oxidase (MAO)-A inhibitor or recent (within 2 weeks) use of an MAO-A inhibitor [see Drug Interactions (7.2) and Clinical Pharmacology (12.3)] • Hypersensitivity to IMITREX (angioedema and anaphylaxis seen) [see Warnings and Precautions (5.10)] • Severe hepatic impairment [see Clinical Pharmacology (12.3)]

Pregnancy

Pregnancy Category C: There are no adequate and well-controlled trials in pregnant women. In developmental toxicity studies in rats and rabbits, oral administration of sumatriptan to pregnant animals was associated with embryolethality, fetal abnormalities, and pup mortality. When administered by the intravenous route to pregnant rabbits, sumatriptan was embryolethal. Developmental toxicity studies of sumatriptan by the intranasal route have not been conducted. Imitrex Nasal Spray should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Oral administration of sumatriptan to pregnant rats during the period of organogenesis resulted in an increased incidence of fetal blood vessel (cervicothoracic and umbilical) abnormalities. The highest no-effect dose for embryofetal developmental toxicity in rats was 60 mg/kg/day. Oral administration of sumatriptan to pregnant rabbits during the period of organogenesis resulted in increased incidences of embryolethality and fetal cervicothoracic vascular and skeletal abnormalities. Intravenous administration of sumatriptan to pregnant rabbits during the period of organogenesis resulted in an increased incidence of embryolethality. The highest oral and intravenous no-effect doses for developmental toxicity in rabbits were 15 and 0.75 mg/kg/day, respectively.

Oral administration of sumatriptan to rats prior to and throughout gestation resulted in embryofetal toxicity (decreased body weight, decreased ossification, increased incidence of skeletal abnormalities). The highest no-effect dose was 50 mg/kg/day. In offspring of pregnant rats treated orally with sumatriptan during organogenesis, there was a decrease in pup survival. The highest no-effect dose for this effect was 60 mg/kg/day. Oral treatment of pregnant rats with sumatriptan during the latter part of gestation and throughout lactation resulted in a decrease in pup survival. The highest no-effect dose for this finding was 100 mg/kg/day.

Nursing Mothers

Sumatriptan is excreted in human milk following subcutaneous administration. Infant exposure to sumatriptan can be minimized by avoiding breastfeeding for 12 hours after treatment with Imitrex Nasal Spray.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established. Imitrex Nasal Spray is not recommended for use in patients younger than 18 years of age.

Two controlled clinical trials evaluated Imitrex Nasal Spray (5 to 20 mg) in 1,248 adolescent migraineurs aged 12 to 17 years who treated a single attack. The trials did not establish the efficacy of Imitrex Nasal Spray compared with placebo in the treatment of migraine in adolescents. Adverse reactions observed in these clinical trials were similar in nature to those reported in clinical trials in adults.

Five controlled clinical trials (2 single-attack trials, 3 multiple-attack trials) evaluating oral IMITREX (25 to 100 mg) in pediatric patients aged 12 to 17 years enrolled a total of 701 adolescent migraineurs. These trials did not establish the efficacy of oral IMITREX compared with placebo in the treatment of migraine in adolescents. Adverse reactions observed in these clinical trials were similar in nature to those reported in clinical trials in adults. The frequency of all adverse reactions in these patients appeared to be both dose- and age-dependent, with younger patients reporting reactions more commonly than older adolescents.

Postmarketing experience documents that serious adverse reactions have occurred in the pediatric population after use of subcutaneous, oral, and/or intranasal IMITREX. These reports include reactions similar in nature to those reported rarely in adults, including stroke, visual loss, and death. A myocardial infarction has been reported in a 14‑year‑old male following the use of oral IMITREX; clinical signs occurred within 1 day of drug administration. Clinical data to determine the frequency of serious adverse reactions in pediatric patients who might receive subcutaneous, oral, or intranasal IMITREX are not presently available.

Geriatric Use

Clinical trials of Imitrex Nasal Spray did not include sufficient numbers of patients aged 65 and older to determine whether they respond differently from younger patients. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other drug therapy.

A cardiovascular evaluation is recommended for geriatric patients who have other cardiovascular risk factors (e.g., diabetes, hypertension, smoking, obesity, strong family history of CAD) prior to receiving Imitrex Nasal Spray [see Warnings and Precautions (5.1)].

Imitrex Nasal Spray contains sumatriptan, a selective 5-HT1B/1D receptor agonist. Sumatriptan is chemically designated as 3-[2-(dimethylamino)ethyl]-N-methyl-indole-5-methanesulfonamide, and it has the following structure:

The empirical formula is C14H21N3O2S, representing a molecular weight of 295.4. Sumatriptan is a white to off-white powder that is readily soluble in water and in saline.

Each Imitrex Nasal Spray contains 5 or 20 mg of sumatriptan in a 100-μL unit dose aqueous buffered solution containing monobasic potassium phosphate NF, anhydrous dibasic sodium phosphate USP, sulfuric acid NF, sodium hydroxide NF, and purified water USP. The pH of the solution is approximately 5.5. The osmolality of the solution is 372 or 742 mOsmol for the 5- and 20-mg Imitrex Nasal Spray, respectively.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis: In carcinogenicity studies in mouse and rat in which sumatriptan was administered orally for 78 and 104 weeks, respectively, there was no evidence in either species of an increase in tumors related to sumatriptan administration.

Carcinogenicity studies of sumatriptan using the nasal route have not been conducted.

Mutagenesis: Sumatriptan was negative in in vitro(bacterial reverse mutation [Ames], gene cell mutation in Chinese hamster V79/HGPRT, chromosomal aberration in human lymphocytes) and in vivo (rat micronucleus) assays.

Impairment of Fertility: When sumatriptan was administered by subcutaneous injection to male and female rats prior to and throughout the mating period, there was no evidence of impaired fertility at doses up to 60 mg/kg/day. When sumatriptan (5, 50, or 500 mg/kg/day) was administered orally to male and female rats prior to and throughout the mating period, there was a treatment-related decrease in fertility secondary to a decrease in mating in animals treated with doses greater than 5 mg/kg/day. It is not clear whether this finding was due to an effect on males or females or both.

Fertility studies of sumatriptan using the intranasal route have not been conducted.

Animal Toxicology and/or Pharmacology

Corneal Opacities: Dogs receiving oral sumatriptan developed corneal opacities and defects in the corneal epithelium. Corneal opacities were seen at the lowest dose tested, 2 mg/kg/day, and were present after 1 month of treatment. Defects in the corneal epithelium were noted in a 60‑week study. Earlier examinations for these toxicities were not conducted and no-effect doses were not established.