In the pharmaceutical industry, the combination of Rifampicin and Isoniazid (often referred to as RH or brands like Rifinah) is the cornerstone of the Continuation Phase of Tuberculosis (TB) treatment. As a pharmacist and manufacturer, I must emphasize that for standard pulmonary TB, this combination is strictly a once-a-day medication.

At your WHO-GMP facility in Mumbai, where you likely produce these as Fixed-Dose Combinations (FDCs), maintaining this “single daily dose” protocol is vital for patient compliance and preventing drug-resistant TB.

The Standard Dosing Protocol

• Frequency: Once daily.

• The “Empty Stomach” Mandate: For maximum efficacy, it must be taken 30 to 60 minutes before breakfast or at least 2 hours after a meal.

• Technical Rationale: Food, especially high-fat meals, significantly delays the absorption of Rifampicin and reduces its peak plasma concentration, which can lead to treatment failure.

• Duration: In a standard 6-month TB regimen, this combination is typically used during the final 4 months (the Continuation Phase).

Mechanism: Dual-Pathway Bactericidal Action

Taking both drugs together at the same time creates a synergistic effect that kills both active and semi-dormant bacteria.

Rifampicin (RNA Block): It inhibits the bacterial enzyme DNA-dependent RNA polymerase, preventing the bacteria from making essential proteins.

Isoniazid (Wall Block): It inhibits the synthesis of mycolic acids, destroying the waxy, protective cell wall unique to Mycobacterium tuberculosis.

The Combined Effect: Taking them together ensures that no bacteria “escape” the treatment, effectively sterilizing the lesion.

The Pharmacist’s “Technical Warning”

• The “Orange” Alert: Warn patients that Rifampicin will turn their urine, sweat, and tears an orange-red color. It is harmless but can permanently stain soft contact lenses.

• Liver Monitoring: Both drugs are hepatotoxic. Patients must be monitored for jaundice, nausea, or loss of appetite, which are signs of liver stress.

• Vitamin B6 (Pyridoxine): It is standard practice to co-administer Vitamin B6 with this daily dose to prevent the peripheral neuropathy (tingling/numbness) often caused by Isoniazid.

The Manufacturer’s Perspective: Technical & Export

From a production and B2B standpoint at your facility in Mumbai:

• The “Stability” Challenge: Rifampicin is highly hygroscopic (moisture-sensitive). In FDC form, it can interact with Isoniazid under humid conditions. Utilizing Alu-Alu blister packaging is the industry standard to ensure a 36-month shelf life in Zone IVb tropical regions.

• Weight-Based FDCs: On your marketplace, highlight that you offer different strengths (e.g., 150/75, 300/150) to allow for precise weight-based dosing, which is the current WHO recommendation for global TB tenders.

• Dossier Support: We provide full CTD/eCTD Dossiers to support your firm’s registration in international health tenders (WHO/Global Fund).