To : Kate
Re : Using shorter half-life products

While it is true that long half-life products, or sustained release products
keep the plasma level at a more uniform plasma level, it is also true that
this could lead to higher milk levels with some drugs.  Is this clinically
relevant ?  Well,  this largely depends on the drug.  With the case of
Effexor,  I would surmise that the sustained release formulation might lead
to slightly higher milk levels, as compared to the non-sustained release
product, but we don't have any data on this yet.  This is assuming the
mother could breastfeed "away" from the transient peaks (at 2 hrs)  when
milk levels were reportedly higher.  This is largely a theoretical issue,
and is so dependent on the drug that it is difficult to answer.  But as a
general rule,  sustained release products should be viewed as a long half-
life products.


Re:  Fluvastatin

Jack,  Me thinketh thou protesteth too much!  (spelling??)

  I thought we were agreeing, mostly.  I still think it is wrong to expose a
neonate to one of the HMG CoA reductase inhibitors, particularly for
specious reasoning.  It's kind of like taking phenobarbital because you
"might" have a seizure 50 years from now.

While it is true that the oral bioavailability of fluvastatin  is low,
please remember that the GI absorption of fluvastatin is relatively good (>
90%), but it is sequestered first pass (> 90%) in the liver (which is why
the 'absolute' oral bioavailability is poor < 24%).  So virtually any in the
milk, would find its way to the neonates liver, where it works to reduce all
hepatic sterols.  Will this have an untoward effect on an infant, I doubt
it, but it's possible.

I still think it is advisable for the mom to simply refuse to take these
meds while she is breastfeeding.  After all, it is her choice.

Regards

Tom Hale, Ph.D.






Regards

Tom Hale, R.Ph., Ph.D.
Associate Professor of Pediatrics

http://neonatal.ttuhsc.edu/lact/