FDA changes safety label of oseltamivir for oral suspension

The concentration of the influenza drug oseltamivir (Tamiflu, Genentech) for oral suspension has been reduced from 12 mg/mL to 6 mg/mL as part of a product safety update conducted by the FDA.

The update was conducted to reduce the likelihood of prescribing and dosing problems that can lead to errors in medication. Genentech has participated in the process of making the changes.

The lower concentration of the drug is less likely to become frothy when shaken, according to an FDA press release. This will allow health care professionals to more accurately measure the dose. Other changes include:

• A change in the measurements of the oral dosing device from milligrams to milliliters.
• A change in the dosing table to include a column for the volume 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 capsules in an emergency situation only if the commercially manufactured drug for oral suspension is unavailable.

The company has begun distribution of the new product and has instituted a voluntary return program for wholesalers, distributors and pharmacies to remove the 12 mg/mL concentration from the market. The FDA encouraged participation in the return program but noted that no quality issues exist for the 12 mg/mL product.

The 12 mg/mL concentration will be taken off the market when supplies expire. The FDA noted that health care professionals should be aware that both concentrations will be on the market for some time and should be vigilant as the next influenza season approaches.

The packaging, dosing device and adverse events may change and patients should be notified of this if they are prescribed oseltamivir. However, pediatric doses have not changed.

Pharmacies are reminded that the return program extends until Aug. 13, 2011, that each prescription should contain a concentration and dose and that the unit of measurement matches the dosing device.

David W. Kimberlin

This modification in oseltamivir oral suspension formulation is a welcome development on the part of the U.S. Food and Drug Administration and Genentech/Roche. The issue of bubbles in the suspension formulation was first recognized and reported in 2008 during the conduct of a study of oseltamivir pharmacokinetics in infants under 1 year of age conducted by the NIAID Collaborative Antiviral Study Group between 2007 and 2010. Other clinicians also recognized the issue in 2009 (N Engl J Med 2009;361:1912-13). While there will need to be education relating to dosing with the new drug concentration, the overall effect of this change should be more reliable and consistent oseltamivir drug exposure in treated children.

David W. Kimberlin, MD
Infectious Diseases in Children Editorial Board member

Edward A. Bell

Whenever dosing instructions for pediatric medication products can be simplified, this is always welcomed. This is the purpose for the change in Tamiflu liquid suspension. Over the past several years, differences in doses expressed as "mg" and "mL" have led to confusion and medication errors in children with various different products.

With the use of a new dosing device to include dose measurement as "mL," it is hoped that fewer dosing errors and less confusion will occur. Prescribers can help to minimize confusion by documenting a child's dose of Tamiflu on the order as both a "mg" and a "mL" dose, and by listing the strength of the product. Including the weight of the child on the order can additionally help to assure that a correct dose is prescribed.

Edward A. Bell, PharmD, BCPS
Infectious Diseases in Children Editorial Board member

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