What are the contraindications for oseltamivir (Tamiflu)?

Oseltamivir Contraindications

The only absolute contraindication to oseltamivir is known serious hypersensitivity to oseltamivir or any component of the product, including severe allergic reactions such as anaphylaxis, toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme. 1

Absolute Contraindication

• Known serious hypersensitivity reactions to oseltamivir or any product component constitute the sole FDA-labeled contraindication 1
• Severe allergic manifestations include anaphylaxis, toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme 1

Important Clinical Considerations (Not Contraindications)

Pregnancy

• Pregnancy is NOT a contraindication to oseltamivir use 2
• Pregnant women with suspected or confirmed influenza should receive oseltamivir immediately without waiting for diagnostic test results, as they face higher risk for complications including maternal death, stillbirths, preterm delivery, and low birth weight 2
• While oseltamivir is classified as "Pregnancy Category C" due to lack of clinical trial data, extensive post-marketing surveillance has demonstrated no adverse effects among women who received oseltamivir during pregnancy or their infants 3, 2
• The standard adult dose of 75 mg twice daily for treatment (or 75 mg once daily for prophylaxis) should be used without modification 2

Renal Impairment

• Renal insufficiency requires dose adjustment but is not a contraindication 4
• For creatinine clearance 10-30 mL/min: reduce treatment dose to 75 mg once daily for 5 days 4
• For prophylaxis with creatinine clearance 10-30 mL/min: use 30 mg once daily for 10 days or 75 mg every other day 4

Pediatric Use

• No age-based contraindications exist; oseltamivir is approved for infants as young as 2 weeks of age 4
• Preterm infants require lower weight-based dosing due to immature renal function, but this represents a dosing adjustment rather than a contraindication 4

Drug Interactions

• Live attenuated influenza vaccine (LAIV) should not be given within 48 hours before oseltamivir use, and oseltamivir should not be used for 14 days after LAIV vaccination (this is a timing consideration for vaccine effectiveness, not a safety contraindication) 4
• Probenecid increases oseltamivir carboxylate plasma levels approximately twofold through competitive renal tubular secretion, but this does not constitute a contraindication—only a potential interaction requiring awareness 3

Common Pitfalls to Avoid

• Do not withhold oseltamivir from pregnant women based on the "Pregnancy Category C" designation—the benefits clearly outweigh theoretical risks, and real-world safety data are reassuring 2
• Do not confuse adverse effects with contraindications—nausea and vomiting (occurring in approximately 10% and 9% of adults respectively) are common but manageable side effects that can be reduced by taking oseltamivir with food 3, 2
• Do not avoid use in patients with underlying respiratory disease—this is a contraindication for zanamivir (the inhaled neuraminidase inhibitor), not for oral oseltamivir 3
• Monitor patients, particularly adolescents, for neuropsychiatric events (self-injury, delirium, abnormal behavior), as these have been reported in post-marketing surveillance, predominantly in Japan 3, 2