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Antiviral Drugs: Summary of Side Effects
Amantadine and Rimantadine
Among some healthy adults and children, side effects can include central nervous system (CNS) side effects such as nervousness, anxiety, difficulty concentrating, and lightheadedness, and gastrointestinal side effects like nausea and loss of appetite. CNS side effects happen more often among persons taking amantadine than among persons taking rimantadine. Among some other persons with long-term illnesses, more serious side effects, such as delirium, hallucinations, agitation, and seizures, can occur. Side effects usually diminish and disappear after 1 week.
Zanamivir
This drug is inhaled and can cause side effects, especially in those with asthma or other chronic lung disease. Decreased respiratory function and bronchospasm have been reported with use of zanamivir. Zanamivir is generally not recommended for use in persons with underlying lung disease such as asthma and chronic obstructive pulmonary disease. Other side effects reported by less than 5% of those who have used this drug are diarrhea, nausea, sinusitis, nasal infections, bronchitis, cough, headache, and dizziness.
Oseltamivir
The side effects reported most often in those people who took this drug were gastrointestinal (i.e., nausea and vomiting). Nausea and vomiting may be less severe if oseltamivir is taken with food.
Note: On November 13, 2006, FDA approved a labeling supplement for Roche Laboratories’ Tamiflu (Oseltamivir Phosphate) to include a precaution about neuropsychiatric events. The revision is based on postmarketing reports (mostly from Japan) of self-injury and delirium with the use of Tamiflu in patients with influenza. The reports were primarily among pediatric patients. The relative contribution of the drug to these events is not known. However, people with the flu, particularly children, may be at an increased risk of self-injury and confusion shortly after taking Tamiflu and should be closely monitored for signs of unusual behavior. A healthcare professional should be contacted immediately if the patient taking Tamiflu shows any signs of unusual behavior. Visit http://www.fda.gov/medwatch/safety/2006/safety06.htm#tamiflu for more information.
Related Links
Prevention & Control of Influenza - Recommendations of the Advisory Committee on Immunization Practices (ACIP) 2008. MMWR 2008 Jul 17; Early Release:1-60.
Prevention & Control of Influenza – Recemmendations of the Advisory Committee on Immunization Practices (ACIP) 2005. MMWR 2005 Jul 29; 54(RR08);1-40.
For more information, see
- When to Use Antiviral Drugs for the Flu
- Antivira Information for Health Professionals
- Additional Links, Information, and Resources on Antiviral Drugs for Influenza
- Page last updated December 19, 2006
- Content Source: Coordinating Center for Infectious Diseases (CCID)
- National Center for Immunization and Respiratory Diseases (NCIRD)
