Oseltamivir: What to Know Before You Take It

1 INDICATIONS AND USAGE Oseltamivir phosphate for oral suspension is an influenza neuraminidase inhibitor (NAI) indicated for: Treatment of acute, uncomplicated influenza A and B in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. ( 1.1 ) Prophylaxis of influenza A and B in patients 1 year and older. ( 1.2 ) Limitations of Use : Not a substitute for annual influenza vaccination. ( 1.3 ) Consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use. ( 1.3 ) Not recommended for patients with end-stage renal disease not undergoing dialysis. ( 1.3 ) 1.1 Treatment of Influenza Oseltamivir phosphate for oral suspension is indicated for the treatment of acute, uncomplicated illness due to influenza A and B infection in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. 1.2 Prophylaxis of Influenza Oseltamivir phosphate for oral suspension is indicated for the prophylaxis of influenza A and B in patients 1 year and older. 1.3 Limitations of Use Oseltamivir phosphate for oral suspension is not a substitute for early influenza vaccination on an annual basis as recommended by the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices. Influenza viruses change over time. Emergence of resistance substitutions could decrease drug effectiveness. Other factors (for example, changes in viral virulence) might also diminish clinical benefit of antiviral drugs. Prescribers should consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use oseltamivir phosphate for oral suspension [see Microbiology (12.4) ] . Oseltamivir phosphate for oral suspension is not recommended for patients with end-stage renal disease not undergoing dialysis [see Dosage and Administration (2.4) and Use in Specific Populations (8.6) ].

5 WARNINGS AND PRECAUTIONS Serious skin/hypersensitivity reactions such as Stevens-Johnson Syndrome, toxic epidermal necrolysis and erythema multiforme: Discontinue oseltamivir phosphate for oral suspension and initiate appropriate treatment if allergic-like reactions occur or are suspected. ( 5.1 ) Neuropsychiatric events: Patients with influenza, including those receiving oseltamivir phosphate for oral suspension, particularly pediatric patients, may be at an increased risk of confusion or abnormal behavior early in their illness. Monitor for signs of abnormal behavior. ( 5.2 ) 5.1 Serious Skin/Hypersensitivity Reactions Cases of anaphylaxis and serious skin reactions including toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme have been reported in postmarketing experience with oseltamivir phosphate for oral suspension. Stop oseltamivir phosphate for oral suspension and institute appropriate treatment if an allergic-like reaction occurs or is suspected. The use of oseltamivir phosphate for oral suspension is contraindicated in patients with known serious hypersensitivity to oseltamivir phosphate for oral suspension [see Contraindications (4) and Adverse Reactions (6.2) ] . 5.2 Neuropsychiatric Events There have been postmarketing reports of delirium and abnormal behavior leading to injury, and in some cases resulting in fatal outcomes, in patients with influenza who were receiving oseltamivir phosphate for oral suspension [see Adverse Reactions (6.2) ] . Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made but they appear to be uncommon based on oseltamivir phosphate for oral suspension usage data. These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution. The contribution of oseltamivir phosphate for oral suspension to these events has not been established. Influenza can be associated with a variety of neurologic and behavioral symptoms that can include events such as hallucinations, delirium, and abnormal behavior, in some cases resulting in fatal outcomes. These events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease. Closely monitor oseltamivir phosphate for oral suspension treated patients with influenza for signs of abnormal behavior. If neuropsychiatric symptoms occur, evaluate the risks and benefits of continuing oseltamivir phosphate for oral suspension for each patient. 5.3 Risk of Bacterial Infections There is no evidence for efficacy of oseltamivir phosphate for oral suspension in any illness caused by pathogens other than influenza viruses. Serious bacterial infections may begin with influenza-like symptoms or may coexist with or occur as complications during the course of influenza. Oseltamivir phosphate for oral suspension has not been shown to prevent such complications. Prescribers should be alert to the potential for secondary bacterial infections and treat them as appropriate. 5.4 Fructose Intolerance in Patients with Hereditary Fructose Intolerance Fructose can be harmful to patients with hereditary fructose intolerance. One dose of 75 mg oseltamivir phosphate for oral suspension delivers 2 grams of sorbitol. This is above the daily maximum limit of sorbitol for patients with hereditary fructose intolerance and may cause dyspepsia and diarrhea. 5.4 Fructose Intolerance in Patients with Hereditary Fructose Intolerance Fructose can be harmful to patients with hereditary fructose intolerance. One dose of 75 mg oseltamivir phosphate for oral suspension delivers 2 grams of sorbitol. This is above the daily maximum limit of sorbitol for patients with hereditary fructose intolerance and may cause dyspepsia and diarrhea.

Oseltamivir has 4 documented drug interaction(s) and 0 food interaction(s) in clinical databases. Always provide your complete medication list to your clinician.