What is the recommended dosing regimen for common medications?

Recommended Dosing Regimens for Common Medications

The recommended dosing regimens for common medications should follow established guidelines from major medical societies, with appropriate adjustments based on patient factors such as age, weight, renal function, and specific disease states. 1

Tuberculosis Medications

First-Line TB Drugs

• Isoniazid (INH):

  • Adults: 5 mg/kg daily (max 300 mg) or 15 mg/kg (max 900 mg) two or three times weekly
  • Children: 10-15 mg/kg daily (max 300 mg) or 20-30 mg/kg (max 900 mg) twice weekly 1

• Rifampin (RIF):

  • Adults: 10 mg/kg daily (max 600 mg) or 10 mg/kg (max 600 mg) two or three times weekly
  • Children: 10-20 mg/kg daily (max 600 mg) or 10-20 mg/kg (max 600 mg) twice weekly 1

• Pyrazinamide (PZA):

  • Adults: 25-40 mg/kg daily
  • Children: 15-30 mg/kg daily (max 2.0 g) or 50 mg/kg (max 4 g) twice weekly 1

• Ethambutol (EMB):

  • Adults: 15-25 mg/kg daily
  • Children: 15-20 mg/kg daily (max 1.0 g) or 50 mg/kg (max 4 g) twice weekly 1

Multi-Drug Resistant TB (MDR-TB) Medications

• Levofloxacin: 750-1,000 mg daily for adults; 15-20 mg/kg/day once daily for children 1
• Moxifloxacin: 400-800 mg daily for adults; 10-15 mg/kg/day once daily for children 1
• Bedaquiline: 400 mg daily for 14 days, then 200 mg three times weekly for adults 1
• Linezolid: 600 mg daily for adults; 10 mg/kg once daily for children >12 years 1

Nontuberculous Mycobacterial (NTM) Infections

• Azithromycin: 250-500 mg daily or 500 mg three times weekly 1, 2
• Clarithromycin: 500 mg twice daily or 500 mg twice daily three times weekly 1
• Rifampin: 10 mg/kg (450-600 mg) daily or 600 mg three times weekly 1
• Ethambutol: 15 mg/kg daily or 25 mg/kg three times weekly 1

Infective Endocarditis Treatment

• Vancomycin:

  • Adults: 30-60 mg/kg/day IV in 2-4 divided doses (max 2 g daily)
  • Children: 40 mg/kg/day IV divided every 8-12 hours (max 2 g daily) 1

• Gentamicin:

  • Adults: 3-5 mg/kg/day IV divided every 8 hours
  • Children: 3-6 mg/kg/day IV divided every 8 hours 1

• Ceftriaxone:

  • Adults: Up to 4 g daily
  • Children: 100 mg/kg/day IV divided every 12 hours or 80 mg/kg/day IV every 24 hours 1

MRSA Infections

• Vancomycin:

  • Adults: 30-60 mg/kg/day IV in 2-4 divided doses
  • Children: 15 mg/kg/dose IV every 6 hours 1

• Linezolid:

  • Adults: 600 mg IV/PO every 12 hours
  • Children: 10 mg/kg/dose PO/IV every 8 hours (not to exceed 600 mg/dose) 1

• Daptomycin:

  • Adults: 6 mg/kg/dose IV daily (osteomyelitis: 6-10 mg/kg/dose)
  • Children: 6-10 mg/kg/dose IV daily 1

Dosing Considerations in Special Populations

Renal Impairment

• Aminoglycosides (amikacin, streptomycin): Reduce dose or increase dosing interval (e.g., 15 mg/kg, 2-3 times/week) 1
• Ethambutol: Increase dosing interval (e.g., 15-25 mg/kg, 3 times/week) 1
• Levofloxacin: Administer 3 times/week in reduced renal function 1
• Cycloserine: Start with 250 mg daily and verify with therapeutic drug monitoring 1

Hepatic Impairment

• Rifampin/Rifabutin: Use with caution 1
• Isoniazid: Use with caution 1
• Clofazimine: Use with caution in severe hepatic impairment 1

Common Pitfalls in Medication Dosing

• Failure to adjust for renal function: Many medications require dose adjustments in renal impairment to prevent toxicity 1
• Incorrect weight-based dosing: Using actual body weight when ideal body weight is more appropriate can lead to overdosing 1
• Drug interactions: Particularly important with rifampin, which induces cytochrome P450 enzymes and can reduce levels of many medications 1, 2
• Inadequate monitoring: Therapeutic drug monitoring is essential for medications with narrow therapeutic indices 1
• Inappropriate frequency: Some medications require specific dosing intervals to maintain therapeutic levels 1

Treatment Duration Considerations

• Tuberculosis: Standard treatment duration is 6 months for drug-susceptible TB, extended to 9 months for patients with cavitary disease and positive cultures after 2 months of treatment 1
• MRSA infections: Duration varies by site - bacteremia (2 weeks), osteomyelitis (>6 weeks), meningitis (14 days) 1
• Infective endocarditis: Generally 4-6 weeks, with longer therapy for recurrent or prosthetic valve endocarditis 1

By following these evidence-based dosing recommendations and considering patient-specific factors, clinicians can optimize therapeutic outcomes while minimizing adverse effects.