Ethambutol

Frequency Not Defined

Acute gout or hyperuricemia

Abdominal pain

Anaphylaxis

Anorexia

Confusion, disorientation

Fever

Headache

LFT abnormalities

Malaise

Nausea

Optic neuritis; symptoms may include decreased acuity, color blindness or visual defects (usually revrsible with discontinuation, though irreversible blindness has been reported)

Peripheral neuritis

Pruritis

Rash

Vomiting

Ethambutol eliminates certain bacteria that cause tuberculosis (TB). It is used with other medicines to treat tuberculosis and to prevent you from giving the infection to others.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking ethambutol,

• tell your doctor and pharmacist if you are allergic to ethambutol or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially antacids and vitamins. Antacids interfere with ethambutol, making it less effective. Take ethambutol 1 hour before or 2 hours after antacids.
• tell your doctor if you have or have ever had kidney disease, gout, or eye disorders such as cataracts.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking ethambutol, call your doctor.

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

• loss of appetite
• upset stomach
• vomiting
• numbness and tingling in the hands or feet

If you experience any of the following symptoms, call your doctor immediately:

• blurred vision
• inability to see the colors red and green
• sudden changes in vision
• skin rash
• itching

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).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Tell your doctor if you have ever used tuberculosis medicine before. Your dose may be different if you have been treated for tuberculosis in the past.

You may take ethambutol with or without food.

Ethambutol may be taken with food if it upsets your stomach.

Tell your doctor if you have any changes in weight. Ethambutol doses are based on weight and your dose may also need to be changed.

Your vision will need to be checked often while you are taking ethambutol. If you wear glasses, take them with you to your vision examination.

Your blood cells, kidney function, and liver function may also need to be checked.

Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Ethambutol will not treat a viral infection such as the flu or a common cold.

Tuberculosis is sometimes treated with a combination of drugs. Use all medications as directed by your doctor. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice.

Store at room temperature away from moisture and heat.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Ethambutol may be found in some form under the following brand names:

• Myambutol

Ethambutol is part of the drug class:

• Other drugs for treatment of tuberculosis

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take aluminum-containing antacids. Oral absorption of ethambutol may be reduced by these products.

If you take too much ethambutol, call your local Poison Control Center or seek emergency medical attention right away.

Take the missed dose as soon as you remember. If it is almost time for the next regularly scheduled dose, skip the missed dose and take the next one as directed. Do not take a double dose of this medication.

MYAMBUTOL may produce decreases in visual acuity, including irreversible blindness, which appear to be due to optic neuritis. Optic neuropathy including optic neuritis or retrobulbar neuritis occurring in association with ethambutol therapy may be characterized by one or more of the following events: decreased visual acuity, scotoma, color blindness, and/or visual defect. These events have also been reported in the absence of a diagnosis of optic or retrobulbar neuritis.

Patients should be advised to report promptly to their physician any change of visual acuity.

The change in visual acuity may be unilateral or bilateral and hence each eye must be tested separately and both eyes tested together. Testing of visual acuity should be performed before beginning MYAMBUTOL therapy and periodically during drug administration, except that it should be done monthly when a patient is on a dosage of more than 15 mg per kilogram per day. Snellen eye charts are recommended for testing of visual acuity. Studies have shown that there are definite fluctuations of one or two lines of the Snellen chart in the visual acuity of many tuberculous patients not receiving MYAMBUTOL.

The following table may be useful in interpreting possible changes in visual acuity attributable to MYAMBUTOL.

In general, changes in visual acuity less than those indicated under “Significant Number of Lines” and “Decrease Number of Points” may be due to chance variation, limitations of the testing method, or physiologic variability. Conversely, changes in visual acuity equaling or exceeding those under “Significant Number of Lines” and “Decrease Number of Points” indicate need for retesting and careful evaluation of the patient's visual status. If careful evaluation confirms the magnitude of visual change and fails to reveal another cause, MYAMBUTOL should be discontinued and the patient reevaluated at frequent intervals. Progressive decreases in visual acuity during therapy must be considered to be due to MYAMBUTOL.

If corrective glasses are used prior to treatment, these must be worn during visual acuity testing. During 1 to 2 years of therapy, a refractive error may develop which must be corrected in order to obtain accurate test results. Testing the visual acuity through a pinhole eliminates refractive error. Patients developing visual abnormality during MYAMBUTOL treatment may show subjective visual symptoms before, or simultaneously with, the demonstration of decreases in visual acuity, and all patients receiving MYAMBUTOL should be questioned periodically about blurred vision and other subjective eye symptoms.

Recovery of visual acuity generally occurs over a period of weeks to months after the drug has been discontinued. Some patients have received MYAMBUTOL (ethambutol hydrochloride) again after such recovery without recurrence of loss of visual acuity. Other adverse reactions reported include: hypersensitivity, anaphylactic/anaphylactoid reaction, dermatitis, erythema multiforme, pruritus, and joint pain; anorexia, nausea, vomiting, gastrointestinal upset, and abdominal pain; fever, malaise, headache, and dizziness; mental confusion, disorientation, and possible hallucinations; thrombocytopenia, leukopenia, and neutropenia. Numbness and tingling of the extremities due to peripheral neuritis have been reported. Elevated serum uric acid levels occur and precipitation of acute gout has been reported. Pulmonary infiltrates, with or without eosinophilia, also have been reported during MYAMBUTOL therapy. Liver toxicities, including fatalities, have been reported. (See WARNINGS). Since MYAMBUTOL is recommended for therapy in conjunction with one or more other antituberculous drugs, these changes may be related to the concurrent therapy. Hypersensitivity syndrome consisting of cutaneous reaction (such as rash or exfoliative dermatitis), eosinophilia, and one or more of the following: hepatitis, pneumonitis, nephritis, myocarditis, pericarditis. Fever and lymphadenopathy may be present.

Read the entire FDA prescribing information for Myambutol (Ethambutol)

Ethambutol is an antibiotic that prevents growth of the tuberculous bacteria in the body.

Ethambutol is used to treat tuberculosis (TB), and is usually given together with at least one other tuberculosis medicine.

Ethambutol may also be used for purposes not listed in this medication guide.

You should not use ethambutol if you are allergic to it. You may not be able to take ethambutol if you have an eye condition called optic neuritis (inflammation of nerve fibers behind your eyes). Your doctor will decide if this treatment is right for if you have an eye disorder.

Ethambutol can cause vision problems that may be a sign that you should stop taking the medicine. You may not be able to take ethambutol if you cannot recognize or report any changes in your vision. Young children or debilitated patients may not be able to tell someone about vision problems.

To make sure ethambutol is safe for you, tell your doctor if you have:

• inflammatory eye disorders such as uveitis or iritis;

• eye problems caused by diabetes;

• cataracts;

• liver disease;

• kidney disease; or

• gout.

FDA pregnancy category C. It is not known whether ethambutol will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.

Ethambutol can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Ethambutol should not be given to a child younger than 13 years old.

Avoid taking an antacid containing aluminum hydroxide (Alternagel, Maalox, Mi-Acid, Mylanta, Rulox) within 4 hours after you take ethambutol. Some antacids can make it harder for your body to absorb ethambutol.

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else's drugs.
• Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
• Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
• Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this medicine, please talk with your doctor, nurse, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take ethambutol or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to ethambutol. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Review Date: October 4, 2017

Ethambutol HCl is contraindicated in patients who are known to be hypersensitive to this drug. It is also contraindicated in patients with known optic neuritis unless clinical judgment determines that it may be used. Ethambutol HCl is contraindicated in patients who are unable to appreciate and report visual side effects or changes in vision (e.g., young children, unconscious patients).

NDC 54879-001-01 (100ct Bottle)

Ethambutol Hydrochloride Tablets, USP 100mg (Film Coated)

AVERAGE ADULT DAILY DOSAGE:

15 mg/kg, or 25 mg/kg once every 24 hours.

See enclosed circular.

100 Tablets Rx only

This package not for household dispensing. Dispense in light containers as defined in the USP.

STI Pharma, LLC

NDC 54879-001-00 (10ct Blister Pack)

Ethambutol Hydrochloride Tablets, USP 100mg (Film Coated)

AVERAGE ADULT DAILY DOSAGE:

15 mg/kg, or 25 mg/kg once every 24 hours.

See enclosed circular.

100 Tablets Rx only

This package not for household dispensing. Dispense in light containers as defined in the USP.

STI Pharma, LLC

NDC 54879-002-01 (100ct Bottle)

Ethambutol Hydrochloride Tablets, USP 400mg (Film Coated)

AVERAGE ADULT DAILY DOSAGE:

15 mg/kg, or 25 mg/kg once every 24 hours.

See enclosed circular.

100 Tablets Rx only

This package not for household dispensing. Dispense in light containers as defined in the USP.

STI Pharma, LLC

NDC 54879-002-00 (10ct Blister Pack)

Ethambutol Hydrochloride Tablets, USP 400mg (Film Coated)

AVERAGE ADULT DAILY DOSAGE:

15 mg/kg, or 25 mg/kg once every 24 hours.

See enclosed circular.

100 Tablets Rx only

This package not for household dispensing. Dispense in light containers as defined in the USP.

STI Pharma, LLC

• Ethambutol HCl
• Ethambutol Hydrochloride

• Myambutol

• Antitubercular Agent

Mycobacterium avium (MAC), secondary prophylaxis or treatment: HIV-exposed/-infected (off-label use): Oral: Infants and Children: 15 to 25 mg/kg/day once daily (maximum: 2.5 g/day) with clarithromycin (or azithromycin) with or without rifabutin (CDC, 2009)

Tuberculosis, pulmonary (drug-susceptible) (excludes meningitis): Oral: Note: Always administer in combination with other antitubercular drugs.

ATS/CDC/IDSA Drug-susceptible tuberculosis guideline recommendations (Nahid 2016):

Dosing:

Once-daily therapy: Note: The preferred frequency of administration is once daily; however, 5-days-per-week administration by directly observed therapy (DOT) is an acceptable alternative.

Infants, Children, and Adolescents <15 years and ≤40 kg: 15 to 25 mg/kg/dose once daily

Children and Adolescents <15 years and >40 kg and Adolescents ≥15 years: Refer to adult dosing.

Three-times-weekly DOT: Note: Although suggested dosing based on experience with twice-weekly regimen; experts suggest three-times-weekly regimens are more effective than twice-weekly DOT regimens; consult guidelines for specific information.

Infants, Children, and Adolescents <15 years, weighing ≤40 kg: 50 mg/kg/dose administered 3 times weekly.

Children and Adolescents <15 years weighing >40 kg or Adolescents ≥15 years: Refer to adult dosing.

Regimens: Refer to adult dosing. Note: As an approach to avoid ethambutol associated ocular toxicity, some clinicians use a 3-drug regimen of isoniazid, rifampin, and pyrazinamide in the initial 2 months of treatment for children who are HIV-uninfected, do not have a history of TB treatment, are living in an area of low prevalence of drug-resistant TB, and have not had exposure to individuals who are from an area of high prevalence of drug-resistant TB; however, the AAP and most experts do include ethambutol as part of the intensive-phase regimen for treatment of TB.

Concerns related to adverse effects:

• Hepatic toxicity: Has been reported, possibly due to concurrent therapy. Monitor liver function prior to and during treatment.

• Optic neuritis: May cause optic neuritis (unilateral or bilateral), resulting in decreased visual acuity or other vision changes. Discontinue promptly in patients with changes in vision, color blindness, or visual defects (effects normally reversible, but reversal may require up to a year). Irreversible blindness has been reported. Monitor visual acuity prior to and during therapy.

Disease-related concerns:

• Ocular disease: Evaluation of visual acuity changes may be more difficult in patients with cataracts, optic neuritis, diabetic retinopathy, and inflammatory conditions of the eye; consideration should be given to whether or not visual changes are related to disease progression or effects of therapy.

• Renal impairment: Use with caution in patients with renal impairment; dosage modification recommended. Monitor renal function prior to and during treatment.

Special populations:

• Pediatric: Use only in children whose visual acuity can accurately be determined and monitored (not recommended for use in children <13 years of age unless the benefit outweighs the risk).

Applies to ethambutol: oral tablet

Ocular

Ocular side effects have included decreased visual acuity (including irreversible blindness), thought to be caused by optic neuritis. Optic neuropathy (including optic neuritis or retrobulbar neuritis), scotoma, color blindness, and visual defect have been reported.[Ref]

Retrobulbar neuritis resulting in blurred vision and loss of red-green vision occurs commonly with ethambutol therapy and requires careful monitoring of visual acuity and color discrimination. Optic neuritis occurs more frequently at dosages greater than 15 mg/kg/day. Drug therapy should be discontinued at the first sign of vision defects. Damage may include central or peripheral fibers of the optic nerve. Scotomas are a common occurrence. Damage generally occurs after 2 months of therapy but may occur more rapidly. Predisposing factors may include decreased renal function, diabetes, and preexisting optic neuritis due to alcohol or tobacco consumption. Although vision defects are generally reversible over several months after discontinuation of ethambutol, cases of irreversible blindness and other ocular damage have been reported.

Ocular toxicity may be more severe in patients with renal impairment, possibly due to drug accumulation.[Ref]

Metabolic

Hyperuricemia has been reported in up to 66% of patients receiving ethambutol and is not dependent on the dose. Occasionally, it has led to joint arthralgias and gouty arthritis after 1 to 2 months of therapy. Symptoms generally resolved within 15 days of discontinuing the drug.[Ref]

Metabolic side effects have included hyperuricemia and precipitation of acute gout.[Ref]

Hepatic

Hepatic side effects have included liver toxicities (including fatalities). Transient and asymptomatic elevations in liver function tests have occurred in 10% of patients. Jaundice has been reported rarely.[Ref]

Elevations in liver function tests, usually without changes in serum bilirubin, have occurred in up to 10% of patients treated with ethambutol. These changes resolved spontaneously despite continuation of drug therapy. Asymptomatic jaundice has also occurred rarely with ethambutol therapy.[Ref]

Hypersensitivity

Hypersensitivity side effects have included hypersensitivity syndrome and anaphylactic/anaphylactoid reaction. Hypersensitivity reactions have included fever, cutaneous reactions (such as rash or exfoliative dermatitis), eosinophilia with or without drug-induced pulmonary infiltrates, hepatitis, pneumonitis, nephritis, pericarditis, lymphadenopathy, anaphylaxis, lichen-planus reactions, and toxic epidermal necrolysis.[Ref]

Hypersensitivity reactions have presented as spiking fever, rash, nausea, hypotension, and eosinophilia. Lichen-planus-like reactions including hyperpigmentation and desquamation have occurred rarely, as well as toxic epidermal necrolysis.[Ref]

Hematologic

Hematologic side effects have included thrombocytopenia, leukopenia, and neutropenia.[Ref]

Respiratory

Respiratory side effects have included pulmonary infiltrates with or without eosinophilia.[Ref]

Gastrointestinal

Gastrointestinal complaints are infrequent with ethambutol therapy and may be associated with a hypersensitivity reaction. Pseudomembranous colitis has been reported when ethambutol was given with rifampin and isoniazid.[Ref]

Gastrointestinal side effects have included nausea, vomiting, abdominal pain, anorexia, and gastrointestinal upset. Pseudomembranous colitis has been reported.[Ref]

Nervous system

Nervous system side effects have included headache, dizziness, and numbness and tingling of the extremities due to peripheral neuritis.[Ref]

Psychiatric

Psychiatric side effects have included mental confusion, disorientation, and possible hallucinations.[Ref]

Dermatologic

Dermatologic side effects have included dermatitis, erythema multiforme, and pruritus.[Ref]

Other

Other side effects have included fever and malaise.[Ref]

Musculoskeletal

Musculoskeletal side effects have included joint pain.[Ref]

Renal

Renal side effects have rarely included reversible renal insufficiency.[Ref]

Renal abnormalities include increases in serum creatinine and idiosyncratic interstitial nephritis.[Ref]

Some side effects of ethambutol may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

CrCl less than 10 mL/min: The usual dose may be administered every 48 hours.

CrCl 10 to 50 mL/min: The usual dose may be administered every 24 to 36 hours.

Ethambutol or streptomycin are used as part of a combination therapy with isoniazid, rifampin, and pyrazinamide. If susceptibility to isoniazid and rifampin is shown, ethambutol may be discontinued.

Ethambutol has been assigned to a pregnancy category C by the FDA. There are no controlled data in human pregnancy. There are reports of ophthalmic abnormalities occurring in infants born to women on antituberculous therapy that included ethambutol. Ethambutol should only be given during pregnancy when benefit outweighs risk.

Ethambutol crosses the placenta. In one patient, maternal blood, placental blood and cord blood concentrations were 5.5, 5.0, and 4.1, respectively, immediately following delivery. No adverse effects were reported in the infant who had been exposed since 23 weeks gestation. Bobrowitz and colleagues studied 42 pregnancies which involved ethambutol exposure in addition to other antituberculous agents. The majority of these pregnancies were treated throughout gestation. No consistent pattern was noted in the reported fetal adverse effects, which included supernumerary nipple, small umbilical hernia, mild right tibial torsion, congenital dislocation of hips, left hydrocele, minimal metatarsus adductus, and skin tag on finger. Other reports also have not associated ethambutol with teratogenic effects. The initial therapy of active tuberculosis in pregnant patients recommended by the Centers for Disease Control and Prevention includes ethambutol. Ethambutol is also recommended by the American Thoracic Society in cases of suspected drug-resistant tuberculosis.