What is isoniazid pyridoxine hydrochloride used for?
In the pharmaceutical industry, the combination of Isoniazid (INH) and Pyridoxine Hydrochloride (Vitamin B6) is the gold standard for both the treatment and prophylaxis of Tuberculosis (TB). As a pharmacist and manufacturer, I view this as a “preventative combination”: Isoniazid kills the bacteria, while Pyridoxine prevents the most common neurological side effect of the treatment.
Primary Clinical Uses
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Active Tuberculosis: Used as a core component of the “RIPE” regimen (Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol) for the treatment of Mycobacterium tuberculosis.
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Latent TB Infection (LTBI): Often used as monotherapy for 6–9 months to prevent a dormant infection from becoming active.
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TB Prophylaxis: Prescribed for individuals in close contact with TB patients or immunocompromised patients (such as those with HIV) who are at high risk of infection.
The Dual Mechanism: Action vs. Protection
1. Isoniazid (The Bactericidal Agent)
Isoniazid is a prodrug that is activated by the mycobacterial enzyme KatG.
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Mechanism: It inhibits the synthesis of mycolic acids, which are essential components of the waxy mycobacterial cell wall.
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Result: Without a cell wall, the bacteria lose structural integrity and die.
2. Pyridoxine Hydrochloride (The Neuroprotective Agent)
Isoniazid interferes with the metabolism of Vitamin B6 in the human body.
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The Problem: INH forms a complex with Vitamin B6 and inhibits the enzyme pyridoxine kinase, leading to a deficiency.
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The Result: Without Pyridoxine, patients often develop peripheral neuropathy (tingling, numbness, or “pins and needles” in the hands and feet).
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The Solution: Including Pyridoxine in the tablet prevents this nerve damage, ensuring better patient compliance during long-term TB therapy.
The Manufacturer’s Perspective: Formulation & Export
From a production standpoint in a WHO-GMP facility, this combination is a high-demand “Essential Medicine”:
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Fixed-Dose Combination (FDC) Stability: Isoniazid is sensitive to moisture and can react with certain excipients (reducing sugars like lactose) through the Maillard reaction, which can cause the tablets to discolor. We utilize specialized, non-reactive diluents to ensure stability.
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Dose Ratios: While INH is typically 100 mg or 300 mg, the Pyridoxine dose is usually 10 mg to 50 mg. We utilize validated blending processes to ensure micro-dose uniformity of the Vitamin B6 across the entire batch.
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Packaging for Global Trade: TB is endemic in high-humidity regions. We utilize Alu-Alu or high-barrier PVC/PVDC blister packaging to ensure a 36-month shelf life for export to Zone IVb regions (Africa, SE Asia, and CIS countries).
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B2B & Public Health Tenders: This product is a staple for the Global Drug Facility (GDF) and national TB programs. Our Mumbai facility provides the necessary CTD/eCTD Dossiers to support international supply.