Codeine and Chlorpheniramine ER Tablets

Name: Codeine and Chlorpheniramine ER Tablets

Indications and Usage for Codeine and Chlorpheniramine ER Tablets

CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE is indicated for the relief of cough and symptoms associated with upper respiratory allergies or a common cold in adults 18 years of age and older.

Important Limitations of Use

Not indicated for pediatric patients under 18 years of age [see Use in Special Population (8.4)]

Codeine and Chlorpheniramine ER Tablets Dosage and Administration

Adults 18 Years of Age and Older

CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE should be administered orally at a dosage of one tablet every 12 hours, not to exceed 2 tablets in 24 hours.

Warnings and Precautions

Death Related to Ultra-Rapid Metabolism of Codeine to Morphine

Respiratory depression and death have occurred in children who received codeine in the post-operative period following tonsillectomy and/or adenoidectomy and had evidence of being ultra-rapid metabolizers of codeine (i.e., multiple copies of the gene for cytochrome P450 isoenzyme 2D6 or high morphine concentrations). Deaths have also occurred in nursing infants who were exposed to high levels of morphine in breast milk because their mothers were ultra-rapid metabolizers of codeine. [see Use in Specific Populations (8.3)]

Some individuals may be ultra-rapid metabolizers because of a specific CYP2D6 genotype (gene duplications denoted as *1/*1xN or *1/*2xN). The prevalence of this CYP2D6 phenotype varies widely and has been estimated at 0.5 to 1% in Chinese and Japanese, 0.5 to 1% in Hispanics, 1 to 10% in Caucasians, 3% in African Americans, and 16 to 28% in North Africans, Ethiopians, and Arabs. Data are not available for other ethnic groups. These individuals convert codeine into its active metabolite, morphine, more rapidly and completely than other people. This rapid conversion results in higher than expected serum morphine levels. Even at labeled dosage regimens, individuals who are ultra-rapid metabolizers may have life-threatening or fatal respiratory depression or experience signs of overdose (such as extreme sleepiness, confusion, or shallow breathing). [see Overdosage (10)]

Children with obstructive sleep apnea who are treated with codeine for post-tonsillectomy and/or adenoidectomy pain may be particularly sensitive to the respiratory depressant effects of codeine that has been rapidly metabolized to morphine. CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE is contraindicated for post-operative pain management in all pediatric patients undergoing tonsillectomy and/or adenoidectomy [see Contraindications (4)].

When prescribing codeine-containing drugs, healthcare professionals should choose the lowest effective dose for the shortest period of time and inform patients and caregivers about these risks and the signs of morphine overdose. [see Use in Specific Populations (8),Overdosage (10)]

Risks from Concomitant Use with Benzodiazepines or other CNS Depressants

Concomitant use of opioids, including CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE, with benzodiazepines, or other CNS depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Because of these risks, avoid use of opioid cough medications in patients taking Benzodiazepines, other CNS depressants, or alcohol [see Drug Interactions (7.1)].

Observational studies have demonstrated that concomitant use of opioid analgesics and benzodiazepines increases the risk of drug-related mortality compared to use of opioids alone. Because of similar pharmacologic properties, it is reasonable to expect similar risk with concomitant use of opioid cough medications and benzodiazepines, other CNS depressants, or alcohol.

Advise both patients and caregivers about the risks of respiratory depression and sedation if CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE is used with benzodiazepines, alcohol, or other CNS depressants. [see Patient Counseling Information (17)]

Respiratory Depression

Codeine, one of the active ingredients in CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE, produces dose-related respiratory depression by directly acting on brain stem respiratory centers.

Overdose of codeine in adults has been associated with fatal respiratory depression, and the use of codeine in children has been associated with fatal respiratory depression. Exercise caution when administering CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE because of the potential for respiratory depression. If respiratory depression occurs, discontinue CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE and use naloxone hydrochloride when indicated to antagonize the effect and other supportive measures as necessary. [see Overdosage (10)].

Drug Dependence

Codeine can produce drug dependence of the morphine type and, therefore, has the potential for being abused. Psychological dependence, physical dependence, and tolerance may develop upon repeated administration of CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE. Prescribe and administer CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE with the same degree of caution appropriate to the use of other opioid drugs. [see Drug Abuse and Dependence (9.2, 9.3)]

Head Injury and Increased Intracranial Pressure

The respiratory depression effects of opioids and their capacity to elevate cerebrospinal fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions, or a pre-existing increase in intracranial pressure. Furthermore, opioids produce adverse reactions that may obscure the clinical course of patients with head injuries. The use of CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE should be avoided in these patients.

Activities Requiring Mental Alertness

Codeine and chlorpheniramine, the active ingredients in CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE, may produce marked drowsiness and impair the mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. Advise patients to avoid engaging in hazardous tasks requiring mental alertness and motor coordination after ingestion of CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE. Concurrent use of CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE with alcohol or other central nervous system depressants should be avoided because additional impairment of central nervous system performance may occur.

Obstructive Bowel Disease

Chronic use of opioids, including codeine, may result in obstructive bowel disease especially in patients with underlying intestinal motility disorders. Codeine may cause or aggravate constipation. Use with caution in patients with underlying intestinal motility disorders.

Acute Abdominal Conditions

CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE should be used with caution in patients with acute abdominal conditions since the administration of codeine may obscure the diagnosis or clinical course of patients with acute abdominal conditions. The concurrent use of other anticholinergics with codeine may produce paralytic ileus. [see Drug Interactions (7.3)]

Special Risk Patients

As with other opioids, CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE should be used with caution in elderly or debilitated patients and those with asthma, persistent or chronic cough, hypothyroidism, Addison's disease, prostatic hypertrophy or urethral stricture. The usual precautions should be observed and the possibility of respiratory depression should be kept in mind.

Overdosage

No human overdosage data are available for CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE.

Codeine

Overdosage with codeine is characterized by respiratory depression (a decrease in respiratory rate and/or tidal volume, Cheyne-Stokes respiration, cyanosis), extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, and sometimes bradycardia and hypotension. In severe overdosage, apnea, circulatory collapse, cardiac arrest, and death may occur.

Codeine may cause miosis, even in total darkness. Pinpoint pupils are a sign of opioid overdose but are not pathognomonic (e.g., pontine lesions of hemorrhagic or ischemic origin may produce similar findings). Marked mydriasis rather than miosis may be seen with hypoxia in overdose situations.

Chlorpheniramine

Manifestations of chlorpheniramine overdosage may vary from central nervous system depression to stimulation. Central toxic effects are characterized by agitation, anxiety, delirium, disorientation, hallucinations, hyperactivity, sedation, and seizures. Severe overdosage may produce coma, medullary paralysis, and death. Peripheral toxicity includes hypertension, tachycardia, dysrhythmias, vasodilation, hyperpyrexia, mydriasis, urinary retention, and diminished gastrointestinal motility. Dry mouth, pharynx, bronchi, and nasal passages may be observed.

Impaired secretion from sweat glands following toxic doses of drugs with anticholinergic side effects may predispose to hyperthermia.

An adult ingested 400 mg chlorpheniramine with no reported serious adverse effects. Toxic psychosis, a possible class effect from overdose of sedating antihistamines, has been reported with accidental overdose of chlorpheniramine.

Treatment of overdosage consists of discontinuation of CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE together with institution of appropriate therapy.

Give primary attention to re-establishment of adequate respiratory exchange through provision of a patent airway and the institution of assisted or controlled ventilation. The opioid antagonist naloxone hydrochloride is a specific antidote for respiratory depression that may result from overdosage or unusual sensitivity to opioids including codeine. Therefore, an appropriate dose of naloxone hydrochloride should be administered, preferably by the intravenous route, simultaneously with efforts at respiratory resuscitation. For further information, see full prescribing information for naloxone hydrochloride. An antagonist should not be administered in the absence of clinically significant respiratory or circulatory depression. Oxygen, intravenous fluids, vasopressors, and other supportive measures should be employed as indicated. Gastric emptying may be useful in removing unabsorbed drug.

Hemodialysis is not routinely used to enhance the elimination of codeine or chlorpheniramine from the body. Urinary excretion of chlorpheniramine is increased when the pH of the urine is acidic; however, acid diuresis is NOT recommended to enhance elimination in overdose, as the risks of acidemia and acute tubular necrosis in patients with rhabdomyolysis far outweigh any potential benefits.

Codeine and Chlorpheniramine ER Tablets - Clinical Pharmacology

Mechanism of Action

Codeine: Codeine is a semisynthetic narcotic antitussive and analgesic with multiple actions qualitatively similar to those of morphine. The precise mechanism of action of codeine and other opiates is not known; however, codeine is believed to act centrally on the cough center. In excessive doses, codeine will depress respiration. Codeine can produce miosis, euphoria, and physical and physiological dependence.

Chlorpheniramine: Chlorpheniramine is a propylamine derivative antihistamine (H1-receptor antagonist) of the alkylamine class that also possesses anticholinergic and sedative activity. It prevents released histamine from dilating capillaries and causing edema of the respiratory mucosa.

Pharmacokinetics

Absorption

Pharmacokinetic (PK) parameters (Mean ± SD) for CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE in fasting, healthy volunteers are shown in the table below.

PK Parameter

Single-dose

Multiple-dose (BID for 6.5 days)

Codeine

Mean (± SD)

Chlorpheniramine Maleate

Mean (± SD)

Codeine

Mean (± SD)

Chlorpheniramine Maleate

Mean (± SD)

Tmax (h) (Range)

3 (2-12)

6 (4-12)

3 (2-5)

5 (3-7)

Cmax (ng/mL)

46 (11)

9 (3)

AUCinf (ng.h/mL) for single-dose OR AUC12 (ng.h/mL) for multiple-dose

383 (99)

312 (137)

Half life (h)

4 (1)

21 (7)

Not determined

Not determined

Food Effect

The presence of a high-fat, high-calorie meal did not significantly impact the PK parameters of CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE.

Distribution

Codeine has been reported to have an apparent volume of distribution of approximately 3-6 L/kg, indicating extensive distribution of the drug into tissues. About 7-25% of codeine, reportedly, is bound to plasma proteins. Codeine passes the blood brain barrier and the placental barrier. Small amounts of codeine and its metabolite, morphine, are transferred to human breast milk.

Chlorpheniramine is widely distributed throughout the tissues of the body, including the central nervous system. It reportedly has an apparent steady-state volume of distribution of approximately 3.2 L/kg in adults and children and is about 70% bound to plasma proteins. Chlorpheniramine and its metabolites likely cross the placental barrier and are excreted into human breast milk.

Metabolism

About 70-80% of the administered dose of codeine is metabolized by conjugation with glucuronic acid to codeine-6‑ glucuronide (C6G) and via O-demethylation to morphine (about 5-10%) and N-demethylation to norcodeine (about 10%) respectively. UDP-glucuronosyltransferase (UGT) 2B7 and 2B4 are the major enzymes mediating glucurodination of codeine to C6G. Cytochrome P-450 (CYP) 2D6 and CYP3A4 are the major enzymes mediating O-demethylation and N-demethylation of codeine respectively. Morphine and norcodeine are further metabolized by conjugation with glucuronic acid. Morphine and its M6 glucuronide conjugate are pharmacologically active. Whether C6G has pharmacological activity is unknown. Norcodeine and M3 glucuronide conjugate of morphine are generally not considered to be pharmacologically active.

Chlorpheniramine is rapidly and extensively metabolized via demethylation in the liver, forming mono- and didesmethyl derivatives. Oxidative metabolism of chlorpheniramine is catalyzed by cytochrome P-450 2D6.

Elimination

Approximately 90% of the total dose of codeine is excreted through the kidneys, of which approximately 10% is unchanged codeine. Plasma half-life of codeine was observed to be about 4 hours with CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE.

Chlorpheniramine and its metabolites are primarily excreted through the kidneys, with large individual variation. Urinary excretion depends on urine pH and flow rate. Plasma half-life of chlorpheniramine was observed to be about 21 hours with CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE.

Clinical Studies

The efficacy of CODEINE PHOSPHATE AND CHLORPHENIRAMINE MALEATE is based on previously established findings of effectiveness of codeine and chlorpheniramine at the proposed doses.

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