Minocycline Dosing Recommendations
Standard Adult Dosing
For most indications including MRSA skin and soft tissue infections, the recommended dose is 100 mg orally twice daily, or for intravenous administration, a 200 mg loading dose followed by 100 mg every 12 hours. 1, 2, 3
Oral Dosing
- 100 mg twice daily is the standard maintenance dose for adults with skin and soft tissue infections, including MRSA 1, 4
- For acne vulgaris, dosing ranges from 50 mg 1-3 times daily up to 100 mg twice daily depending on severity 4
- Higher doses up to 200 mg daily may be used for severe acne when clinically necessary, though pigmentation risk increases significantly above cumulative doses of 70 grams 5
Intravenous Dosing
- Initial loading dose: 200 mg IV, then 100 mg IV every 12 hours 2, 3
- Maximum daily dose should not exceed 400 mg in 24 hours 3
- The loading dose should be infused over 60 minutes 2
- Reconstitute each 100 mg vial with 5 mL Sterile Water for Injection, then further dilute in 100-1000 mL for infusion 3
Pediatric Dosing
For children ≥8 years old, use weight-based dosing: 4 mg/kg loading dose (maximum 200 mg), then 2 mg/kg every 12 hours (maximum 100 mg/dose). 1, 2, 4
Weight-Based Guidelines
- Children <45 kg: 2 mg/kg/dose every 12 hours 1, 4
- Children ≥45 kg: Use adult dosing of 100 mg twice daily 1, 4
- Children <8 years: Minocycline is contraindicated due to permanent tooth discoloration and enamel hypoplasia risk 4
Duration of Treatment
For skin and soft tissue infections, treat for 7-14 days; for bacteremia, treat for 7-14 days; for plague, treat for 10-14 days. 2, 4
- MRSA skin infections: 7-14 days 2, 4
- Bacteremia: 7-14 days 2
- Plague (bubonic or pharyngeal): 10-14 days 2
- Acne vulgaris: Often requires prolonged therapy (mean 10.5 months in safety studies) 5
Pharmacodynamic Considerations
Minocycline is an AUC/MIC-driven agent, meaning total drug exposure relative to the organism's MIC determines efficacy, not peak concentration. 6
- The free AUC/MIC ratio for bacteriostatic effect is approximately 34, and for a 1-log reduction is approximately 76 6
- At standard human doses (100 mg every 12 hours), dose fractionation (once vs. twice vs. three times daily) shows no difference in efficacy 6
- For organisms with MIC >1 mg/L, standard dosing (200 mg Q12H) may result in suboptimal PK-PD target attainment 7
Special Populations
Critically Ill Patients
- Standard dosing of 200 mg IV every 12 hours may be inadequate for A. baumannii with MIC >1 mg/L 7
- Body surface area affects central volume of distribution; albumin levels affect fraction unbound 7
Elderly/Debilitated Patients
- Elimination half-life is prolonged (mean 25 hours vs. typical 16-18 hours) 8
- Dose adjustment by body weight is recommended: correlation exists between expected trough concentration and dose per kg body weight 8
- Consider using the lower end of the dosing range initially 8
Renal Impairment
- No dose adjustment required, but monitor for adverse effects 4
Hepatic Impairment
- Use with caution; monitor liver function tests, especially with prolonged use 4
Critical Contraindications
- Pregnancy and breastfeeding (absolute contraindication) 4
- Children <8 years old (risk of permanent tooth discoloration) 4
- Systemic lupus erythematosus (risk of exacerbation) 4
- Hypersensitivity to tetracyclines 4
Common Pitfalls to Avoid
- Inadequate treatment duration: Ensure at least 7 days of therapy for skin infections 4
- Ignoring cumulative dose for pigmentation risk: Pigmentation occurs significantly more often with cumulative doses >70 grams 5
- Not adjusting for body weight in elderly: Dosing should account for body weight in debilitated elderly patients 8
- Assuming dose-dependent side effects: Most side effects (except pigmentation) occur at similar rates with 150 mg/day vs. 200 mg/day 9