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Authoritative Clinical Reference
Schedule H
Oral
Form Strength
Tablet 250 mg
INDICATIONS + DOSING — FOR CLINICIAN USE ONLY
Primary Indications (Approved / Standard in India):
▶ Multidrug-Resistant Tuberculosis (MDR-TB) in Adults
Use only as part of multidrug MDR-TB regimen under NTEP protocols or specialist supervision
Parameter Details
Starting dose 250 mg once daily (or 15 mg/kg/day)
Titration Increase by 250 mg every 3–5 days as tolerated to target dose
Usual maintenance dose 500–750 mg/day in 1–2 divided doses
Maximum dose 1 g/day (rarely required)
Duration As per NTEP MDR-TB regimen (typically 18–20 months total treatment)
Key Clinical Notes:
Secondary Indications – Adults Only (Off-label):
▶ Mycobacterium avium Complex (MAC) Infection in HIV — OFF-LABEL
Parameter Details
Starting dose 250 mg once daily
Titration Increase to 500 mg/day as tolerated
Usual maintenance dose 500 mg/day
Maximum dose 500 mg/day
Duration As part of combination regimen; duration per specialist guidance
Supervision Specialist only
Evidence basis Limited data; rarely used in India due to poor tolerance; reserved when preferred agents unavailable
PAEDIATRIC DOSING (Specialist Only)
Primary Indications:
▶ MDR-TB under Paediatric MDR Regimen (as per NTEP)
Weight Band Starting Dose Titration Usual Maintenance Dose Maximum Dose
5–9 kg 62.5 mg once daily Gradual increase as tolerated 15–20 mg/kg/day in 1–2 divided doses 125 mg/day
10–15 kg 125 mg once daily Gradual increase as tolerated 15–20 mg/kg/day in 1–2 divided doses 250 mg/day
16–23 kg 187.5 mg once daily Gradual increase as tolerated 15–20 mg/kg/day in 1–2 divided doses 375 mg/day
24–30 kg 250 mg once daily Gradual increase as tolerated 15–20 mg/kg/day in 1–2 divided doses 500 mg/day
31–45 kg 375 mg once daily Gradual increase as tolerated 15–20 mg/kg/day in 1–2 divided doses 750 mg/day
45 kg 500 mg once daily Gradual increase as tolerated 15–20 mg/kg/day in 1–2 divided doses 750 mg/day
Key Clinical Notes:
Safety Monitoring:
Secondary Indications – Paediatrics (Off-label):
Not established outside MDR-TB under programmatic management. Use only under NTEP specialist-led regimens.
Age Restriction Statement:
May be used in children of all ages under specialist supervision for MDR-TB as per NTEP guidelines. Use in children <6 years requires careful specialist oversight due to formulation limitations and monitoring challenges.
| eGFR (ml/min/1.73m²) | Recommendation |
|---|---|
| eGFR (ml/min/1.73m²) | Recommendation |
| Haemodialysis | No supplemental dosing required; administer after dialysis on dialysis days |
| Peritoneal dialysis | No dose adjustment required |
Note: Ethionamide is primarily metabolized hepatically; renal excretion is minimal.
| Hepatic Impairment | Recommendation |
|---|---|
| Mild impairment (Child-Pugh A) Start at lower end of dosing range (250 mg/day) | ; monitor LFTs closely |
| Moderate impairment (Child-Pugh B) | Use with caution; reduce dose if GI or neurological side effects occur; frequent LFT monitoring |
| Severe impairment (Child-Pugh C) | Avoid — high risk of hepatotoxicity |
Parameter Recommendation
Risk category Not formally classified in India; use only if benefit outweighs risk
Overall safety Limited human data; animal studies inconclusive
Preferred alternatives Not applicable for MDR-TB (no safer second-line alternatives); first-line drugs preferred for drug-sensitive TB
When may be used In MDR-TB when resistance pattern requires; under specialist supervision
Monitoring Maternal LFTs, thyroid function; fetal growth surveillance; ensure pyridoxine supplementation
Parameter Recommendation
Excretion in milk Unknown quantity; likely excreted
Compatibility WHO recommends breastfeeding may continue during MDR-TB treatment if clinically necessary
Preferred alternatives Not applicable for MDR-TB (essential component of regimen)
Infant monitoring Hepatic function, feeding pattern, weight gain, signs of GI upset
Additional notes Mother should receive pyridoxine supplementation; consider pyridoxine for breastfed infant if prolonged exposure
Parameter Recommendation
Starting dose 250 mg once daily (lower end of range)
Titration Slower titration (increase every 5–7 days) due to increased risk of adverse effects
Additional risks Increased susceptibility to peripheral neuropathy, CNS effects (confusion, depression), hepatotoxicity
Special considerations Monitor LFTs, mental status, and neurological function closely; ensure pyridoxine co-administration
Interacting Drug/Class Mechanism / Risk Recommendation
Cycloserine Additive CNS toxicity — confusion, psychosis, seizures Avoid combination if possible; if essential, use with close neuropsychiatric monitoring
Para-aminosalicylic acid (PAS) Synergistic hypothyroidism risk Monitor thyroid function (TSH) monthly; treat hypothyroidism if develops
Alcohol Additive hepatotoxicity; may precipitate psychotic reactions Avoid alcohol use during treatment
Isoniazid Additive peripheral neuropathy and hepatotoxicity Avoid concurrent use in same regimen if possible (rarely co-administered in MDR-TB)
Interacting Drug/Class Mechanism / Risk Recommendation
Antidiabetic agents (metformin, sulfonylureas, insulin) Ethionamide may worsen glycaemic control Monitor blood glucose frequently; adjust antidiabetic therapy as needed
Clofazimine Additive GI intolerance Monitor for severe GI symptoms; may require dose adjustment of either drug
Linezolid Cumulative risk of peripheral and optic neuropathy Monitor vision and peripheral neuropathy symptoms closely
Bedaquiline / Delamanid Part of MDR-TB regimens; monitor for overlapping toxicities Use as per NTEP protocols with appropriate monitoring
Phenytoin Ethionamide may increase phenytoin levels Monitor phenytoin levels if co-administered
Adverse Effect Notes
Hepatotoxicity May be severe; requires immediate discontinuation if significant transaminase elevation (>5× ULN) or clinical hepatitis
Optic neuritis Requires urgent ophthalmologic evaluation; may necessitate drug discontinuation
Peripheral neuropathy May be irreversible if not recognized early; ensure pyridoxine prophylaxis
Depression and psychosis Stop drug if symptoms severe; psychiatric evaluation required
Seizures Rare; more likely with concurrent cycloserine use
Gynaecomastia Reported with prolonged use
Stevens-Johnson syndrome Rare; requires immediate discontinuation and hospitalisation
| Timing | Parameters |
|---|---|
| Baseline | LFTs (AST, ALT, bilirubin), serum creatinine, TSH, fasting blood glucose, vision screening, weight, neuropsychiatric assessment |
Early treatment (weeks 1–4) LFTs weekly; blood glucose in diabetics; monitor GI tolerance; assess neuropsychiatric status
Maintenance (monthly) LFTs, TSH, weight, peripheral neuropathy screening, vision assessment, mental health review
Long-term Continue monthly monitoring throughout treatment duration; periodic ophthalmologic evaluation if therapy >2 months
Note: Supplied free of cost under NTEP for eligible patients enrolled in MDR-TB treatment programmes.
| Formulation | Approximate Price (per tablet) |
|---|---|
| Tablet 250 mg ₹8–₹20 per tablet (private sector) |
NLEM Status: Not currently listed under NLEM 2022 price control
Government Supply: Available free under NTEP for patients on programmatic MDR-TB treatment
ethionamide; MDR-TB; tuberculosis; second-line antitubercular; NTEP; hepatotoxic; neurotoxicity; pyridoxine; hypothyroidism; Schedule H
RxIndia v1.0 — 28 May 2025
This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.
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