Booster Shots

Oddities, musings and news from the health world

« Previous Post | Booster Shots Home | Next Post »

Dosing confusion for liquid Tamiflu?

September 23, 2009 |  2:30 pm


Confusing directions on liquid suspensions of the antiviral drug Tamiflu may inadvertantly cause parents to give their children either too little of the drug, impeding the child's recovery, or a toxic overdose, physicians warned today in a letter published in the online version of the New England Journal of Medicine. Prescriptions for the drug are often written with doses in fractions of a teaspoon, but the dropper packaged with the drug is marked in milligrams, requiring a difficult conversion  of units, said Dr. Ruth Parker of the Emory University School of Medicine, lead author of the paper.

"It's an egregious error that there is a conflict in the prescription labeling instructions and the dosage device that comes in the exact same box," said co-author Dr. Michael Wolf of the Northwestern University Feinberg School of Medicine. "It's incredibly confusing to parents."


The conflict was discovered by co-author Kara Jacobson, a senior research associate at Emory's Rollins School of Public Health and mother of a 6-year-old girl who contracted pandemic H1N1 influenza, popularly known as swine flu. Their Tamiflu prescription called for three-quarters of a teaspoon of the drug twice a day. Jacobson and her husband, an internist, had to do a Google search and solve a complex equation to determine the correct dose:

5 ml (volume of a tsp) x .75 x 12 mg/ml of Tamiflu = 45 mg

It took them both working together for 30 minutes to solve the equation, and they suspect that many parents would have greater difficulty doing so. Their recommendation: If a prescription calls for teaspoons or fractions of a teaspoon, then the syringe should be marked in teaspoons.

-- Thomas H. Maugh II

Photo: A syringe, marked in milligrams, that came with a Tamiflu prescription and the label calling for a dose of three-quarters of a teaspoon. Credit: New England Journal of Medicine

Post a comment
If you are under 13 years of age you may read this message board, but you may not participate.
Here are the full legal terms you agree to by using this comment form.

Comments are moderated, and will not appear until they've been approved.

If you have a TypeKey or TypePad account, please Sign In

Comments (2)

Its not that difficult.... you can and should ask questions at the pharmacy counter if you don't know what you're doing... Everyones has the right to be counsled about their Rx (sadly many care more about whats on sale that day than what they're putting in their body)

I totally agree with the author.


The Latest | news as it happens

Recent Posts
test |  March 15, 2011, 4:00 pm »
Booster Shots has moved |  July 12, 2010, 6:02 pm »