Is isoniazid used for TB?

In the pharmaceutical industry, Isoniazid (also known as INH) is the “Gold Standard” first-line agent used for both the treatment and prevention of Tuberculosis (TB). As a pharmacist and manufacturer, I view this molecule as the cornerstone of anti-tubercular therapy, whether used alone for latent infection or in combination for active disease.

At your WHO-GMP facility in Mumbai, you likely manufacture this in 100 mg and 300 mg tablets, as well as pediatric oral suspensions and injectable forms.

Primary Clinical Indications

• Active Tuberculosis: Used as a vital part of the standard four-drug regimen (Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol/Streptomycin) for 6–9 months.

• Latent Tuberculosis: Used as monotherapy to prevent TB from becoming active in high-risk individuals (e.g., those exposed to TB or with weakened immunity).

• Nontuberculous Mycobacteria: Occasionally used off-label for atypical infections like M. avium complex.

Mechanism: Cell Wall Synthesis Inhibition

Isoniazid is a prodrug that must be activated by the bacteria themselves to work.

Activation: The mycobacterial enzyme Catalase-peroxidase (KatG) converts Isoniazid into its active form.

Targeting InhA: The active drug inhibits the InhA protein (an NADH-dependent reductase).

Mycolic Acid Blockade: This prevents the synthesis of mycolic acids, which are essential lipids required for the protective mycobacterial cell wall.

Bactericidal Action: Without a cell wall, actively growing bacteria cannot survive.

The Pharmacist’s “Technical Warning”

As you build clinical authority on your digital platforms, providing these safety insights is essential:

• Hepatotoxicity: Isoniazid can cause severe, sometimes fatal, hepatitis. Alcohol must be strictly avoided as it significantly increases the risk of liver damage.

• Peripheral Neuropathy: A common side effect is numbness or “pins and needles” in the hands and feet. This is caused by a Vitamin B6 (Pyridoxine) deficiency.

• The “Pyridoxine Protocol”: It is standard practice to co-prescribe 25–50 mg of Vitamin B6 daily to prevent nerve damage, especially in pregnant women, the elderly, and those with diabetes.

• Empty Stomach Rule: For maximum bioavailability, Isoniazid should be taken 1 hour before or 2 hours after meals.

Safety in Pregnancy and Breastfeeding

For your maternal health portfolio, it is important to note:

• Pregnancy: Isoniazid is recommended for active TB in pregnancy. While it crosses the placenta, it is not considered teratogenic.

• Lactation: It is considered compatible with breastfeeding by the WHO and CDC. The concentration in breast milk is low, but the infant should be monitored for jaundice, and the mother must continue taking Vitamin B6.

The Manufacturer’s Perspective: Technical & Export

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

• The “Slow/Fast Acetylator” Factor: Isoniazid is metabolized in the liver by acetylation. “Slow acetylators” have higher drug levels and a greater risk of toxicity, while “fast acetylators” may require higher doses.

• FDC Strategy: On your marketplace, highlight your Fixed-Dose Combinations (FDCs) (e.g., Rifampicin + Isoniazid). FDCs are the global standard for improving patient compliance in TB treatment.

• Stability & Packaging: Isoniazid is stable but should be protected from light and moisture. Utilizing Alu-Alu blister packaging ensures a 36-month shelf life, which is critical for export to Zone IVb tropical regions.

• Dossier Support: We provide full CTD/eCTD Dossiers to support your firm’s registration in international health tenders and for bidding on WHO pre-qualification programs.