Tamiflu (oseltamivir phosphate) for Oral Suspension: Label Change-New Concentration (6 mg/mL)

Labeling changes are being made to Tamiflu oral suspension to reduce the possibility of prescribing and dosing confusion that can lead to medication errors.  The changes to the product label include:

• A change in the concentration of Tamiflu from 12 mg/mL to 6 mg/mL. The lower concentration of Tamiflu is less likely to become frothy when shaken, which helps to ensure an accurate measurement. A change in the measurements of the oral dosing device from milligrams (mg = weight) to milliliters (mL = volume).
• A change in the dosing table for Tamiflu to include a column for the volume (mL) based on the new 6 mg/mL concentration. Revised container labels and carton packaging. Revised compounding instructions for pharmacies to prepare a 6 mg/mL oral suspension from Tamiflu capsules in an emergency situation only if the commercially manufactured Tamiflu for oral suspension is unavailable.

BACKGROUND

Tamiflu is in a class of medications called neuraminidase inhibitors. These drugs work by stopping the spread of the influenza (flu) virus in the body. Genentech, the manufacturer of Tamiflu for oral suspension, plans to begin distribution of the new 6 mg/mL product in July 2011.  The company has instituted a voluntary Take Back Program for wholesale buyers, distributors and pharmacies to remove the 12 mg/mL product from the marketplace. The 12 mg/mL product will remain in the marketplace and in state or national stockpiles until current supplies expire.

RECOMMENDATION

It is important for healthcare professionals to be aware that a patient may potentially receive either concentration (6 mg/mL or 12 mg/mL) from their pharmacy during the next influenza season (2011-2012). Steps should be taken to avoid the potential for a medication error due to confusion between the two concentrations. Prescribers should include the new concentration (6 mg/mL) and dose in milliliters on all prescriptions for Tamiflu for oral suspension