Eprna.org

T h e n e w e ng l a n d j o u r na l o f m e dic i n e Risk of Confusion in Dosing Tamiflu Oral Suspension
in Children
To the Editor: The medical community should
be made aware of the serious potential for dosing errors in children prescribed Tamiflu (oseltami- vir) oral suspension, as illustrated in the case de- After the diagnosis of novel H1N1 influenza, a 6-year old received a prescription for Tamiflu (oseltamivir) oral suspension (12 mg per millili- ter) at a dose of 3/4 teaspoon PO BID. However, the parents, one a primary care physician and the other one of the authors, had great difficulty determining the correct dose to administer to their child. The medication bottle was accompa- nied by a prepackaged syringe with markings of 30, 45, and 60 mg (Fig. 1). The label attached by Figure 1. Tamiflu Package, Label, and Syringe Included
the pharmacy specified the dose in volume units (“3/4 teaspoonful”) but the syringe provided only markings in mass units (milligrams). Despite ing and measurement calculations1 will be re- the disparate directions, the parents were even- quired under the Emergency Use Authorization,2 tually able to determine the correct dose with which has extended the use of oseltamivir to the aid of 1 of 10 tables in the portion of the children under the age of 1 year.
package insert intended for prescribers, not for Unless immediate steps are taken to improve parents. Specifically, they solved the following the prescribing instructions for this drug in equation for the milligram equivalent of the 3/4- children, its safe use will be compromised. We tsp dose: 5 ml (volume of a teaspoon) × 0.75 × 12 recommend that all pharmacies be instructed to mg per milliliter Tamiflu suspension = 45 mg on ensure that the label instructions for use are in the same dosing units as those on the measure- Most families and caregivers would not be ment device dispensed with oseltamivir. For in- able to identify or perform the cumbersome cal- stance, in the present case, the instructions culations required to administer Tamiflu safely could have said, “fill the attached syringe to the to children, because the instructions on the level marked 45 mg and administer this amount pharmacy label, on the manufacturer’s printed twice a day for 5 days.” If a prescription specifies label, and in the accompanying Consumer Med- the dose in teaspoons, only a syringe calibrated ication Information and the prepackage dosing in fractions of a teaspoon should be dispensed syringe are misaligned. Thus, there is a high and the instructions adjusted accordingly; if a chance for dosing errors, compromised treat- prescription specifies the dose in milliliters, ment, or toxic effects. Even more complex dos- only a syringe calibrated in milliliters should be Downloaded from www.nejm.org at HHS LIBRARIES CONSORTIUM on September 28, 2009 . Copyright 2009 Massachusetts Medical Society. All rights reserved. T h e n e w e ng l a n d j o u r na l o f m e dic i n e used. In addition, the Consumer Medication In- Dr. Wolf reports receiving consulting fees from Abbott and formation must be improved and the public Pfizer and grant support from McNeil Pharmaceuticals, and Dr. Wood reports being a partner and investor in Symphony Capital, alerted to the potential for oseltamivir dosing serving as a director of Oxigene Pharmaceuticals, and receiving errors. In the future, all measuring devices for consulting fees from International Reinsurance companies. No use in children should be marked with volumet- other potential conflict of interest relevant to this letter was re- ric doses (milliliters or teaspoons).
This letter (10.1056/NEJMc0908840) was published on Septem- 1. Centers for Disease Control and Prevention. Emergency use
authorization of Tamiflu: fact sheet for patients and parents. July 14, 2009. (Accessed September 22, 2009, at http://www.cdc.
gov/h1n1flu/eua/pdf/tamiflu-patients.pdf.) 2. Idem. Emergency use authorization (EUA) of medical prod-
ucts and devices: Tamiflu (oseltamivir). (Accessed September 22, 2009, at http://www.cdc.gov/h1n1flu/eua/pdf/fda_letter_ Correspondence Copyright 2009 Massachusetts Medical Society. Atlanta, GAAlastair J.J. Wood, M.D.
Symphony Capital New York, NY [email protected] Downloaded from www.nejm.org at HHS LIBRARIES CONSORTIUM on September 28, 2009 . Copyright 2009 Massachusetts Medical Society. All rights reserved.

Source: http://eprna.org/NEJMc0908840v2.pdf