Clinical beta
FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.
Drug Monograph
Isoniazid
Antitubercular (PO, IM)
Indication
Active TB β’ latent TB β’ some NTM
INDICATIONS (CORE USE)
**TB treatment/latent** β **hepatotoxicity**; **peripheral neuropathy** β **pyridoxine B6** with risk factors; **acute overdose** β seizures need **gram-dose pyridoxine**.
ADULT DOSE (STANDARD)
5 mg/kg PO daily TB (max 300 mg); latent 300 mg daily or 900 mg biweekly high-dose regimens
MAX DOSE
300 mg/day standard; 15 mg/kg in intermittent supervised therapy
Route
PO, IM
PEDIATRIC DOSE
10β15 mg/kg/day max 300 mg
Must-not-miss safety points
Major warning
- **Hepatitis** β baseline LFTs risk factors; monthly symptoms education - **Acute overdose** seizures β **pyridoxine** + benzos toxicology - Peripheral neuropathy β alcoholism, diabetes, pregnancy β B6 - Drug-induced lupus rare
USE IF: TB latent/active as program component. AVOID IF: Acute liver failure; cannot monitor; acute isoniazid overdose without ED capability.
Primary
Secondary
STANDARD (ADULT PO)
300 mg PO daily OR 15 mg/kg 2β3Γ/week max 900 mg (DOT)
ADULT DOSE
300 mg PO daily typical; 15 mg/kg 2β3Γ/week DOT max 900 mg
PEDIATRIC DOSE
mg/kg daily.
MAX DOSE
Per DOT program
Practical Note
Pyridoxine 25β50 mg PO daily with INH if neuropathy risk.
Clinical warnings
Adverse effects
Pediatrics
10β15 mg/kg/day max 300 mg
Pregnancy
TB: use with rifampin regimen; add B6
Lactation
compatible with infant B6.
Renal impairment
HD clears β give after dialysis; adjust per program. **CrCl scaffold (FMBM β titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β₯50** β standard TB dosing; **HD** β give after dialysis or supplement per program - **CrCl 10β50** β **HD** timing if applicable β per TB program - **CrCl <10** / **HD** β **HD removes drug** β **post-dialysis dose** or supplement per TB program
Hepatic impairment
Acute hepatitis β stop all TB meds; restart staged.
Elderly
Hepatotoxicity risk higher.
PO fasting or with food per tolerance; DOT observed.
Clinical Picture
**Life-threatening (first):** **seizures**, **coma**, **metabolic acidosis** (acute massive OD). **Secondary:** chronic hepatotoxicity.
Immediate Actions
ABCs; **pyridoxine (B6)** gram doses for seizures per toxicology; benzos adjunct; charcoal if early
Antidote
Pyridoxine for INH-induced seizures / massive overdose (toxicology dosing); otherwise no additional specific antidote β treat complications (ventilation, acidosis, hepatic failure)
Decontamination
Charcoal if early
Escalation
Refractory seizures, intubation need β **ICU** toxicology; **severe cases β consider hemodialysis** β consult
Common mistakes, resistance logic, and bedside traps
**TB public health workhorse**. **Liver** and **seizures** (acute OD) are the fears. **B6** with neuropathy risks. **Pyridoxine antidote** in massive ingestion.
DOT for adherence. 4-month rifapentine-moxifloxacin latent regimens emerging β follow local program. Never mono TB therapy. *Stewardship (all antimicrobials):* Empiric choice β syndrome severity + **local antibiogram**; shortest effective course.
Hepatic acetylation (fast/slow acetylator); penetrates caseous foci.
Inhibits mycolic acid synthesis (InhA pathway).
Global data (no country-specific data available)
Saudi Arabia
(placeholder β verify local formulary)
Common trade names are curated examples only β formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.
Saudi Arabia
International