The Corpus Callosum

Tamiflu Dosing Errors in Kids

Practitioners are warned that it is astonishingly easy to make dosing
errors with the oral suspension of Tamiflu (oseltamivir).
 This is a product that is mostly given to kids, although it
could be used for adults who have difficulty swallowing, or for anyone
if there is a shortage of the capsules.

The reason: usually, doctors write prescriptions for liquid medications
by specifying the number of milliliters, or sometimes teaspoons, to
administer.  But the dispenser that comes with the product is
marked in milligrams, not milliliters.

This came to attention when a doctor got a prescription for his kid,
that said to give 3/4 teaspoons.  If the prepackaged syringe
had been marked in milliliters, it would have been a straightforward
conversion.  Google could do that easily.  But the
darned thing was marked with lines denoted 30, 45, and 60 mg.  

Granted, the conversion still is not terribly difficult.  But
you get people who’ve been up at night with a sick kid, stressed by
missing work, then had to screw
around with insurance preauthorization
, then ask them to
convert teaspoons to milliliters, then milliliters to milligrams (based
on a particular ratio), it obviously is not a good situation.  

What may not be obvious is this: the doctor who is writing the
prescription may never have seen the product that the patient actually
will get.  They don’t know what it looks like, or how
it is packaged, or what kind of dispenser comes with it.  So
it is not obvious to the doctor, what kind of instructions would be
most helpful.  And it is not obvious to the patient, upon
getting the prescription or the product, that it would be good to ask
for different instructions.  In this situation, patients
should call the pharmacist if there is the slightest doubt about how to
dose the product.  But that is inconvenient, sometimes not
possible (of the pharmacy is closed), and may not occur to someone who
is stressed or otherwise not thinking clearly.  

What IS obvious, is that the USA should adopt the metric system. Today.



  1. #1 Russell
    September 25, 2009

    Let me know when pilots and navigators in Europe start using kilometers instead of nautical miles. The French did this once upon a time. And gave it up.

  2. #2 Joseph j7uy5
    September 27, 2009

    How am I to let you know? You didn’t leave your full name, or email address. Besides, I am reasonably confident that if the USA adopted the metric system, there would be no reason for France or anyone else to keep using nautical miles.

  3. #3 Antoni Jaume
    September 27, 2009

    the reason for the continued use of nautical miles is that the mesh easily with angular measures on maps, since there are 60 nautical miles per degree of longitude, ie one nm is equal to one minute of arc.

    By the way the USA have accepted the metric system, and have been contributors to it, and its successors like the “Système International”, since its inception. What is more the USA Constitution say that Congress has power to “To coin Money, regulate the Value thereof, and of foreign Coin, and fix the Standard of Weights and Measures;”

  4. #4 DNF
    September 29, 2009

    I’m not a doctor, but I’m a father.

    Honestly, is it too terrible to give a child 4ml instead of 2.5ml?

    I live in Mexico and I don’t have that conversion problem. Sometimes when the doctor says give the kids 2.5ml every 8 hours, we try to be very careful, but sometimes we give them 3-4ml at 8.5 ot 7.5 hours… nothing serrious has happen so far.

    This goes for the mg. to ml. conversion. Yeah I know densities are different than water (where mg. ~ ml.) so conversion might not be exactly, but… is it really a serious problem?

    On other hand… yeah, you americans should change to metric.

  5. #5 Monado, FCD
    October 3, 2009

    Whatever happened to prototyping and usability testing? It could prevent lawsuits as well as over/underdosing.

  6. #6 rx1
    October 7, 2009

    I live in Mexico and I don’t have that conversion problem.

  7. #7 Vicki
    October 12, 2009

    Yes, adopting the metric system would help. But if the doctors don’t know that things are marked in milliliters instead of milligrams, there’s still a risk. How close in weight is Tamiflu to water? How about cough syrup?

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