Dosing Liquid Tamiflu Can Be a Prescription for Trouble

September 25, 2009

Be alert for a potential dosing error when you prescribe oral-suspension oseltamivir (Tamiflu).

Be alert for a potential dosing error when you prescribe oral-suspension oseltamivir (Tamiflu) for children with influenza. The dosing dispenser packaged with this formulation of Tamiflu is marked in milligrams (30, 45, and 60 mg) rather than milliliters or teaspoons.

The FDA has received reports of incidents in which the dosing instructions for the patient did not match the dosing dispenser. A recent case involving a 6-year-child with novel H1N1 influenza was published online in the New England Journal of Medicine; fortunately, the error was detected before the medication was administered.

The FDA recommends the following strategies to ensure the appropriate dose is given:
•Doses should be written in milligrams if the dosing dispenser used with the drug is marked in milligrams.
•If the dose is given in milliliters, the pharmacist should provide the patient or caregiver with a new dosing dispenser, such as an oral syringe calibrated in milliliters. The dosing dispenser packaged with the product should be discarded.
•Prescribing oral-suspension oseltamivir in teaspoons should be avoided because this can lead to inaccurate dosing.

A dosing chart that lists appropriate doses of Tamiflu for Oral Suspension (12 mg/mL) for treatment of influenza in children aged 1 year or older is available on the FDA Web site.