What is the most common side effect of Tamiflu (oseltamivir)?

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Last updated: February 8, 2025 • View editorial policy

From the Guidelines

Nausea and vomiting are the most common side effects of Tamiflu (oseltamivir).

Common Side Effects

  • Nausea: approximately 10% in adults and 14% in children
  • Vomiting: approximately 9% in adults and 14% in children These side effects are more frequent in patients receiving oseltamivir compared to those receiving a placebo 1.

Management of Side Effects

Taking oseltamivir with food may help reduce the severity of nausea and vomiting 1.

Other Side Effects

Transient neuropsychiatric events, such as self-injury or delirium, have been reported, but recent analyses have found no increased risk associated with oseltamivir 1. In children, vomiting is a common side effect, reported in 5.8% of patients in one study 2.

From the FDA Drug Label

The most common adverse reactions in the pooled treatment and pooled prophylaxis trials in adults and adolescents are displayed in Table 5 The majority of these adverse reactions were reported on a single occasion, occurred on either the first or second treatment day and resolved spontaneously within 1-2 days. Table 5 Adverse Reactions Occurring in ≥1% of Adults and Adolescents (13 years of age and older) in Treatment and Prophylaxis Trials

  • Gastrointestinal Disorders
    • Nausea 10%
    • Vomiting 8%
  • Nervous System Disorders
    • Headache 2%
  • General Disorders
    • Pain <1%

The most common side effect of Tamiflu (oseltamivir) is nausea, which occurred in 10% of adults and adolescents in the treatment trials, and 8% in the prophylaxis trials 3.

From the Research

Common Side Effects of Tamiflu (Oseltamivir)

  • The most common side effects of Tamiflu (oseltamivir) include: + Nausea + Vomiting + Diarrhea + Abdominal pain
  • These side effects are generally mild and transient, and can be reduced by taking oseltamivir with food 4, 5, 6 ### Neuropsychiatric Adverse Events
  • There have been reports of neuropsychiatric adverse events, including: + Delirium + Behavioral disturbance + Suicide + Delusion + Panic attack + Convulsion + Depressed mood + Loss of consciousness
  • These events are more common in children than in adults and generally occur within 48 hours of administration 7 ### Overall Safety Profile
  • Oseltamivir has a simple and uncomplicated pharmacology, and lacks potential for drug-drug interactions 5
  • The drug is generally well-tolerated, with no important safety concerns that might limit its suitability for the treatment and prevention of influenza in all patient populations 5

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.