A fixed-dose combination (FDC) of three first-line anti-tubercular drugs used primarily in the intensive phase of treatment for drug-susceptible pulmonary and extrapulmonary tuberculosis. This specific low-dose combination is often used in pediatric formulations or for specific weight-band dosing in adults under the Revised National Tuberculosis Control Programme (RNTCP), now known as the National Tuberculosis Elimination Programme (NTEP) in India. It is a cornerstone of Directly Observed Treatment, Short-course (DOTS) strategy.
Adult: Dosing is weight-based as per NTEP guidelines. This specific FDC (50+300+100mg) is typically used for patients in the 16-25kg weight band (e.g., 2 tablets daily). For standard adult dosing (e.g., 30-39kg: 3 tablets; 40-54kg: 4 tablets; 55-69kg: 5 tablets), taken once daily on an empty stomach.
Note: Take all tablets as a single daily dose, preferably 1 hour before or 2 hours after a meal (empty stomach) with water to maximize Rifampicin absorption. Do not break or crush unless specified (some pediatric formulations are dispersible). Adhere strictly to the prescribed duration (usually 2 months intensive phase).
Combination therapy targeting multiple, distinct biochemical pathways in Mycobacterium tuberculosis to achieve bactericidal and sterilizing effects, preventing the emergence of resistance.
Pregnancy: Pregnancy Category C (US FDA). Use only if clearly needed and benefits outweigh risks. All three drugs cross the placenta. Pyrazinamide use in pregnancy is debated but included in WHO and Indian NTEP guidelines. Close monitoring is essential. Supplement with Pyridoxine (Vitamin B6).
Driving: Generally safe. However, patients should be cautioned about dizziness, visual disturbances (optic neuritis - rare), or fatigue which may impair ability.
| Ketoconazole, Itraconazole, Fluconazole | Rifampicin decreases azole levels, reducing antifungal efficacy. | Major |
| Warfarin, Acenocoumarol | Rifampicin increases metabolism, reducing anticoagulant effect. Dose adjustment and frequent INR monitoring needed. | Major |
| Oral Contraceptives, Levonorgestrel | Rifampicin reduces efficacy, leading to contraceptive failure. Alternative non-hormonal methods advised. | Major |
| Antiretroviral Drugs (e.g., Protease Inhibitors, NNRTIs) | Complex bidirectional interactions. Rifampicin significantly lowers levels of many ARVs. Requires expert HIV/TB co-management and regimen adjustment. | Major |
| Phenytoin, Carbamazepine | Rifampicin increases metabolism, reducing anticonvulsant levels. Isoniazid can inhibit metabolism, increasing levels. Monitor levels closely. | Major |
| Prednisolone, Dexamethasone | Rifampicin increases metabolism, reducing corticosteroid efficacy. | Moderate |
| Antacids (Aluminum hydroxide) | May reduce absorption of Isoniazid. Administer at least 2 hours apart. | Moderate |
| Acetaminophen (Paracetamol) | Increased risk of hepatotoxicity, especially with Isoniazid. | Moderate |
| Theophylline | Rifampicin decreases theophylline levels. | Moderate |
| Cyclosporine, Tacrolimus | Rifampicin drastically reduces levels, risking transplant rejection. | Major |
Same composition (Isoniazid (50mg) + Pyrazinamide (300mg) + Rifampicin (100mg)), different brands: