Oseltamivir Side Effects

Some side effects of oseltamivir may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to oseltamivir: oral capsule, oral powder for reconstitution

Stop using oseltamivir and Get emergency medical help if you have any of these signs of an allergic reaction while taking oseltamivir: hives; difficulty breathing; swelling of your face, lips, tongue, or throat; a red and blistering or peeling skin rash.

Some people using oseltamivir have had rare side effects of sudden confusion, delirium, hallucinations, unusual behavior, or self-injury. These symptoms have occurred most often in children. It is not known whether oseltamivir was the exact cause of these symptoms. However, anyone using oseltamivir should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using oseltamivir has any of these symptoms.

Less serious side effects of oseltamivir may include:

• nausea, vomiting, diarrhea;

• dizziness, headache;

• nosebleed;

• eye redness or discomfort;

• sleep problems (insomnia); or

• cough or other respiratory symptoms.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to oseltamivir: oral capsule, oral powder for reconstitution

General

The most common side effects are nausea and vomiting.

The most common side effects reported in patients receiving oseltamivir during studies for the treatment of influenza were nausea, vomiting, bronchitis, insomnia, and vertigo. Nausea and vomiting were generally mild to moderate in severity and usually occurred on the first 2 days of treatment. Less than 1% of patients discontinued oseltamivir early due to nausea and vomiting.

Side effects in prophylaxis studies were similar to those in treatment studies. Side effects that occurred more frequently than in treatment studies were aches and pains, rhinorrhea, dyspepsia, and upper respiratory tract infections.

Gastrointestinal

Gastrointestinal side effects have been the most commonly reported and have included nausea (without vomiting; up to 10%), vomiting (up to 9%), diarrhea (up to 7%), abdominal pain (2%), and pseudomembranous colitis (less than 1%). Gastrointestinal bleeding and hemorrhagic colitis have been reported during postmarketing experience.

Respiratory

Respiratory side effects have included cough (up to 5%) and bronchitis (up to 2%). The incidences were similar or higher among placebo patients and may represent symptoms of underlying influenza infection. Pneumonia has been reported (less than 1%) and may also be a symptom of underlying disease. Nasopharyngitis, congestion, rhinitis, and dry, sore throat have also been reported.

Nervous system

Nervous system side effects have included headache (up to 18%), dizziness (up to 2%), insomnia (1%), and vertigo (up to 1%). The incidences were similar or higher among placebo patients and may represent symptoms of underlying influenza infection. Seizure has been reported during postmarketing experience.

Psychiatric

Psychiatric side effects have included abnormal behavior and delirium (including symptoms such as altered level of consciousness, confusion, delusions, hallucinations, agitation, anxiety, nightmares) during postmarketing experience. Mania has been reported.

Delirium and abnormal behavior leading to injury, with fatal outcomes in some cases, in influenza patients receiving oseltamivir have been reported during postmarketing experience (mostly in Japan). Although frequency is unknown, based on oseltamivir usage, these events appear to be uncommon. These events were primarily reported in pediatric patients and often had an abrupt onset and rapid resolution. Since influenza may be associated with a variety of neurologic and behavioral symptoms (including hallucinations, delirium, and abnormal behavior, with fatal outcomes in some cases) and may occur with encephalitis or encephalopathy but can occur without obvious severe disease, oseltamivir's contribution to these effects has not been established.

Other

Other side effects have included fatigue (up to 8%), humerus fracture (less than 1%), pyrexia (less than 1%), and peritonsillar abscess (less than 1%). Drowsiness and malaise have been reported; however, causality has not been established. Hypothermia has been reported during postmarketing experience.

Hematologic

Hematologic side effects have included anemia (less than 1%). Pancytopenia has been reported; however, causality has not been established.

Hypersensitivity

Hypersensitivity side effects have included allergy, anaphylactic/anaphylactoid reactions, and swelling of the face or tongue during postmarketing experience.

Dermatologic

Dermatologic side effects have included rash, dermatitis, urticaria, eczema, and serious skin reactions (including toxic epidermal necrolysis, Stevens-Johnson syndrome, and erythema multiforme) during postmarketing experience.

Hepatic

Hepatic side effects have included hepatitis and abnormal liver function tests during postmarketing experience. Hepatic failure has been reported; however, causality has not been established.

Cardiovascular

Cardiovascular side effects have included unstable angina (less than 1%). Sudden cardiopulmonary arrest has been reported; however, causality has not been established. Arrhythmia has been reported during postmarketing experience.

Metabolic

Metabolic side effects have included aggravation of diabetes during postmarketing experience. Hyperglycemia has been reported; however, causality has not been established.

Immunologic

Immunologic side effects have included sepsis; however, causality has not been established.

Musculoskeletal

Musculoskeletal side effects have included arthralgia in at least one patient.

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