TB Drug Dosing Calculator — Nigeria · Kenya · Ghana
Weight-based dosing for rifampicin, isoniazid, pyrazinamide, ethambutol & streptomycin.
WHO 2022 consolidated guidelines. Adults and children. Offline-capable.
For qualified healthcare professionals only.
TB drug doses sourced from WHO consolidated guidelines on tuberculosis (2022), BNF for Children 2024, and national TB programme guidelines for Nigeria (NTBLCP), Kenya (DLTLD), and Ghana (NTP).
Always apply clinical judgement. Report an error
Nigeria has the highest tuberculosis burden in Africa and is one of 30 high-burden countries globally, with an estimated 467,000 new TB cases in 2022 (WHO Global TB Report 2023). Nigeria also has among the highest rates of drug-resistant TB in West Africa. Correct weight-band dosing of first-line anti-TB medicines — isoniazid (H), rifampicin (R), pyrazinamide (Z), ethambutol (E) — is critical to achieving adequate serum drug levels, preventing acquired resistance, and ensuring treatment success. WHO 2022 paediatric TB guidelines significantly increased recommended mg/kg doses for children compared to previous guidance, with higher doses for isoniazid and rifampicin particularly in young children and those with HIV co-infection. This calculator applies updated WHO 2022 weight-band tables for both adult FDC and child dispersible FDC tablets.
Intensive phase: 2 months of daily HRZE (isoniazid + rifampicin + pyrazinamide + ethambutol). Continuation phase: 4 months of daily HR (isoniazid + rifampicin). Total: 6 months for drug-sensitive pulmonary TB. Extend continuation phase to 7 months (total 9 months) for TB meningitis. TB bone/joint disease: 9–12 months total.
WHO 2022 paediatric weight-band tables use child-friendly dispersible FDCs with higher mg/kg doses than adults: isoniazid 10 mg/kg/day (range 7–15), rifampicin 15 mg/kg/day (range 10–20), pyrazinamide 35 mg/kg/day (range 30–40), ethambutol 20 mg/kg/day (range 15–25). Six weight bands: 4–7 kg, 8–11 kg, 12–15 kg, 16–24 kg, 25–34 kg, ≥35 kg.
Give pyridoxine 10–25 mg/day with isoniazid for all patients at high risk of peripheral neuropathy: malnutrition, HIV co-infection, diabetes, pregnancy, alcohol dependency, chronic renal failure, or age >65 years. Pyridoxine is not required routinely for healthy adults with drug-sensitive TB on standard regimens, but is always given in Nigerian national TB guidelines for children and high-risk adults.
TB-IRIS (immune reconstitution inflammatory syndrome) occurs in 8–43% of HIV/TB co-infected patients starting ART, typically within 3–6 weeks of ART initiation, presenting as paradoxical worsening of TB symptoms despite microbiological improvement. Management: do not stop either TB treatment or ART. Give prednisolone 1.25 mg/kg/day for 4 weeks then taper over 4 weeks for moderate-severe IRIS. Ensure adequate anti-TB therapy. Rule out treatment failure, drug resistance, and alternative diagnoses. TB-IRIS is a significant cause of early ART-related mortality in Nigeria and East Africa.
TB meningitis requires a minimum of 12 months total treatment — longer than standard pulmonary TB (6 months). The WHO recommended regimen is 2 months of HRZE (intensive phase) followed by 10 months of HR (continuation phase). High-dose rifampicin (15–20 mg/kg/day) is recommended by WHO 2022 guidelines to achieve adequate CNS penetration. Adjunctive dexamethasone significantly reduces mortality and neurological sequelae in TB meningitis and should be given for the first 6–8 weeks: dexamethasone 0.4 mg/kg/day tapered over 6–8 weeks. Pyridoxine supplementation is essential throughout treatment.
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For empirical antibiotic selection before TB confirmation, see the Antibiotic Selector.
📋 Guideline basis: WHO TB Guidelines 2022 · NTBLCP Nigeria · NICE NG33 · Last reviewed: January 2025 · Next review due: January 2026 · Disclaimer · Report an error
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