Myambutol - Comprehensive Usage Guide: instructions, indications, composition, side effects

• Active Ingredient: Ethambutol hydrochloride
• Excipients: May include colloidal silicon dioxide, croscarmellose sodium, magnesium stearate, microcrystalline cellulose, and other inactive ingredients depending on the formulation.

• Tablets: Available in various strengths, including 100 mg, 400 mg, and 800 mg tablets.

Myambutol belongs to the pharmacological group of antimycobacterial agents (ATC code: J04AK02).

• Pharmacodynamics: Ethambutol inhibits the synthesis of mycobacterial cell wall components, particularly arabinogalactan and mycolic acids. This action disrupts the integrity of the cell wall and inhibits bacterial growth. It is primarily active against Mycobacterium tuberculosis and Mycobacterium avium complex.
• Pharmacokinetics: Following oral administration, ethambutol is rapidly absorbed from the gastrointestinal tract. It distributes widely in various body tissues and fluids, including the lungs, cerebrospinal fluid, and ocular tissues. Ethambutol is primarily eliminated via renal excretion, with a small fraction undergoing hepatic metabolism.

Myambutol is indicated for the treatment of tuberculosis (TB) caused by susceptible strains of Mycobacterium tuberculosis. It is often used in combination with other antitubercular agents as part of a multidrug regimen for both active TB disease and latent TB infection.

Myambutol is contraindicated in individuals with a history of hypersensitivity to ethambutol or any component of the formulation. It should not be used in patients with optic neuritis or other preexisting visual disturbances, as ethambutol may exacerbate these conditions.

• Myambutol tablets should be taken orally with a full glass of water, preferably on an empty stomach.
• Dosage adjustments may be necessary in patients with renal impairment to prevent drug accumulation and minimize the risk of adverse effects.

• The recommended dosage of Myambutol varies depending on the patient’s weight, age, renal function, and the severity of the TB infection.
• For the treatment of active TB disease, the usual adult dosage is 15-25 mg/kg of body weight once daily, up to a maximum of 2.5 g daily.
• For latent TB infection, lower doses of 15 mg/kg once weekly or 25 mg/kg once monthly may be used.

Common side effects of Myambutol may include gastrointestinal disturbances (e.g., nausea, vomiting, abdominal pain), headache, dizziness, and rash. Ocular toxicity, including optic neuritis and visual disturbances, is a rare but serious adverse effect that requires immediate medical attention if symptoms occur.

Myambutol tablets should be stored at room temperature (15-30°C) in a dry place, protected from light and moisture. The bottle should be tightly closed when not in use.

Myambutol should be used with caution during pregnancy, especially during the first trimester, and only if the potential benefits outweigh the potential risks to the fetus. It is excreted in breast milk, so breastfeeding should be avoided during Myambutol therapy.

Myambutol does not typically impair cognitive or motor functions. However, patients should be cautious when driving or operating machinery, especially if they experience dizziness or other central nervous system side effects.

Myambutol is an essential component of antitubercular therapy, offering effective treatment for TB infections when used in combination with other medications. By understanding its pharmacological properties, indications, dosage, and precautions, patients and healthcare providers can work together to achieve optimal treatment outcomes. Always consult a healthcare provider for personalized medical advice.