Isoniazid + Rifampicin

Isoniazid + Rifampicin is a antitubercular fixed-dose combination medicine available in Bangladesh under many brand names. Below are its uses, dosage, side effects and precautions — and all brands with their current prices.

• Treatment of drug-susceptible tuberculosis as part of an appropriate combination anti-TB regimen.
• Continuation-phase treatment of tuberculosis when isoniazid and rifampicin are both indicated, according to the prescriber’s regimen and local TB guidelines.

Adult dosing is usually weight-based and depends on the phase of TB treatment, previous treatment history, liver function, other medicines, and national TB guidelines. It is commonly taken once daily, preferably on an empty stomach, unless the doctor advises otherwise. The exact strength, number of tablets or capsules, and treatment duration must be decided by the treating doctor. Do not stop early, miss doses, or change the dose without medical advice, as this can cause treatment failure and drug resistance. Pyridoxine (vitamin B6) may be prescribed with isoniazid, especially in people at higher risk of nerve problems.

• Common: nausea, vomiting, abdominal discomfort, loss of appetite, headache, dizziness, tiredness, rash, itching.
• Rifampicin can cause harmless orange-red discoloration of urine, sweat, saliva, and tears; it may permanently stain soft contact lenses.
• Isoniazid can cause tingling, numbness, or burning pain in the hands or feet, especially if vitamin B6 is low.
• Serious: liver inflammation or hepatitis, jaundice, severe weakness, persistent vomiting, dark urine, pale stools, severe abdominal pain.
• Rare but serious: severe allergic reactions, severe skin reactions, low platelet count with unusual bleeding or bruising, flu-like syndrome, confusion, seizures, or vision changes.

Use Isoniazid + Rifampicin cautiously in people with current or previous liver disease, heavy alcohol use, older age, malnutrition, HIV infection, diabetes, kidney disease, peripheral neuropathy, seizure disorders, or a history of drug-induced hepatitis. Liver function tests and clinical monitoring may be needed. Avoid alcohol during treatment unless the doctor specifically permits it. Tell the healthcare provider about all medicines, herbal products, and contraceptives being used. Use this medicine only under the guidance of a registered doctor or pharmacist.

• Alcohol increases the risk of liver injury and should generally be avoided.
• Rifampicin strongly reduces the effect of many medicines by enzyme induction, including warfarin, oral contraceptives, some antiretrovirals, azole antifungals, some anticonvulsants, corticosteroids, immunosuppressants, methadone, some diabetes medicines, and some anticoagulants.
• Hormonal contraceptives may become less reliable; a non-hormonal or additional contraceptive method should be discussed with a healthcare professional.
• Isoniazid can increase levels or toxicity of medicines such as phenytoin and carbamazepine.
• Antacids containing aluminium may reduce isoniazid absorption if taken too close together.
• High-histamine or high-tyramine foods such as some fish, aged cheese, or fermented foods may occasionally cause flushing, headache, palpitations, or high blood pressure with isoniazid.
• Paracetamol and other potentially liver-toxic medicines should be used carefully and only as advised.

• Known hypersensitivity to isoniazid, rifampicin, rifamycins, or any component of the product.
• Acute liver disease or previous severe liver injury caused by isoniazid or rifampicin.
• Use with medicines for which rifampicin is contraindicated because of major interactions, unless a specialist changes the regimen.
• TB known or suspected to be resistant to isoniazid or rifampicin, unless managed by a TB specialist with an appropriate regimen.

Tuberculosis treatment during pregnancy is important for the health of both mother and baby, and isoniazid plus rifampicin may be used when prescribed by a doctor. The prescriber may recommend vitamin B6 and monitoring for liver problems. Rifampicin near delivery may increase bleeding risk, so medical supervision is important. Both medicines pass into breast milk in small amounts; breastfeeding is usually compatible with treatment when clinically indicated, but the infant should be observed and the mother should follow the doctor’s advice.

Store in a cool, dry place away from direct sunlight, heat, and moisture. Keep the container tightly closed and out of the reach of children. Do not use after the expiry date, and return unused or damaged medicine to a pharmacy or healthcare facility when possible.