First-Line Anti-Tubercular Drugs
Key Points
- HRZE (Isoniazid, Rifampicin, Pyrazinamide, Ethambutol) forms the cornerstone of treatment
- Weight-based dosing is essential in children
- Fixed-dose combinations preferred for better compliance
- Regular monitoring crucial for efficacy and safety
Treatment Principles
- Daily dosing preferred over intermittent
- Treatment duration based on disease severity
- Consideration of age-specific factors
- Importance of adherence support
Individual First-Line Drugs
1. Isoniazid (H/INH)
- Dosage:
- 10 mg/kg (range 7-15 mg/kg) daily
- Maximum dose: 300 mg/day
- Mechanism:
- Inhibits mycolic acid synthesis
- Bactericidal against actively dividing bacilli
- Important Considerations:
- Requires pyridoxine supplementation
- High early bactericidal activity
- Good CSF penetration
- Monitor liver function
2. Rifampicin (R/RIF)
- Dosage:
- 15 mg/kg (range 10-20 mg/kg) daily
- Maximum dose: 600 mg/day
- Mechanism:
- Inhibits bacterial RNA synthesis
- Bactericidal action
- Special Considerations:
- Multiple drug interactions
- Orange discoloration of body fluids
- Take on empty stomach
- Monitor liver function
3. Pyrazinamide (Z/PZA)
- Dosage:
- 35 mg/kg (range 30-40 mg/kg) daily
- Maximum dose: 2000 mg/day
- Mechanism:
- Active in acidic environment
- Effective against intracellular bacteria
- Key Points:
- Essential in intensive phase
- Monitor uric acid levels
- Watch for hepatotoxicity
4. Ethambutol (E/EMB)
- Dosage:
- 20 mg/kg (range 15-25 mg/kg) daily
- Maximum dose: 1200 mg/day
- Mechanism:
- Inhibits arabinogalactan synthesis
- Bacteriostatic action
- Important Considerations:
- Monitor visual acuity and color vision
- Use with caution in young children
- Adjust dose in renal impairment
Treatment Regimens
Standard Treatment Categories
1. New Cases (Category I)
- Intensive Phase (2 months):
- HRZE daily
- Fixed-dose combinations preferred
- Continuation Phase (4 months):
- HR daily
- Extended in specific situations
2. Special Situations
- TB Meningitis:
- Extended treatment duration (9-12 months)
- Higher doses of Rifampicin
- Consider steroids
- Osteoarticular TB:
- Extended continuation phase
- Regular orthopedic assessment
Monitoring and Side Effects
1. Baseline Assessment
- Complete blood count
- Liver function tests
- Renal function tests
- Visual acuity testing (if on EMB)
- Weight documentation
2. Regular Monitoring
- Clinical:
- Monthly weight check
- Growth monitoring
- Symptom assessment
- Treatment adherence
- Laboratory:
- Monthly LFTs in high-risk cases
- Drug levels if poor response
- Vision testing (EMB)
3. Common Side Effects and Management
- Hepatotoxicity:
- Regular LFT monitoring
- Stop drugs if significant elevation
- Sequential reintroduction
- Gastrointestinal:
- Nausea, vomiting
- Give drugs with food
- Consider timing adjustment
- Neurological:
- Peripheral neuropathy (INH)
- Optic neuritis (EMB)
- Proper supplementation
4. Drug Interactions
- Rifampicin interactions:
- Antiretrovirals
- Anticonvulsants
- Oral contraceptives
- Monitor:
- Concurrent medications
- Drug levels if needed
- Clinical response
Disclaimer
The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.
