Tamiflu (Oseltamivir) Prophylaxis Dosing
For adults and adolescents ≥13 years, the standard prophylaxis dose is 75 mg orally once daily for 10 days following exposure to an infected individual, or up to 6 weeks during a community outbreak. 1, 2, 3
Adult and Adolescent Prophylaxis (≥13 years)
- Standard dose: 75 mg once daily 1, 3
- Duration: 10 days for post-exposure prophylaxis (after close contact with infected individual) 1, 3
- Extended duration: Up to 6 weeks during community outbreaks 1, 3
- Immunocompromised patients: May continue prophylaxis for up to 12 weeks 3
- Timing: Initiate within 48 hours of exposure to infected individual for maximum benefit 2, 4
- Administration: Can be taken with or without food, though taking with meals reduces gastrointestinal side effects (nausea occurs in ~10-15% of patients) 2, 4
Pediatric Prophylaxis (1-12 years)
Weight-based dosing is mandatory for children, using once-daily administration: 1
- ≤15 kg (≤33 lb): 30 mg once daily 1
- >15-23 kg (>33-51 lb): 45 mg once daily 1
- >23-40 kg (>51-88 lb): 60 mg once daily 1
- >40 kg (>88 lb): 75 mg once daily 1
- Duration: 10 days post-exposure or up to 6 weeks during community outbreak 1, 3
Infant Prophylaxis (3-11 months)
- Ages 3-8 months: 3 mg/kg once daily 1, 4
- Ages 9-11 months: 3.5 mg/kg once daily 1, 4
- Infants <3 months: Prophylaxis is NOT recommended due to limited safety data unless the situation is judged critical 1, 4
Renal Impairment Dose Adjustments
Dose reductions are mandatory for creatinine clearance <60 mL/min: 1, 2, 4
- CrCl 30-60 mL/min: No adjustment needed for prophylaxis 3
- CrCl 10-30 mL/min: Reduce to 30 mg once daily OR 75 mg every other day (5 total doses over 10 days) 1, 3
- CrCl <10 mL/min: Not recommended 3
- Elderly patients (≥65 years): Use standard adult dosing if renal function is normal, but assess creatinine clearance as renal function declines with age 4
Critical Pitfalls to Avoid
- Do NOT confuse prophylaxis dosing (once daily) with treatment dosing (twice daily) - this is the most common error and leads to either underdosing treatment or overdosing prophylaxis 2, 4
- Do NOT use term infant dosing (3 mg/kg) for preterm infants - this causes toxic drug concentrations due to immature renal function; preterm infants require lower doses based on postmenstrual age 4, 5
- Do NOT forget to adjust doses in renal impairment - failure to reduce doses in patients with CrCl 10-30 mL/min can lead to drug accumulation and toxicity 1, 3
Formulation Details
- Capsules: Available as 30 mg, 45 mg, and 75 mg 3
- Oral suspension: 6 mg/mL concentration when reconstituted from powder 1, 3
- For infants <1 year: Use appropriate measuring device (3 mL or 5 mL oral syringe) instead of standard dosing syringe 4