To :Linda Norton
Re :Ritalin
Unfortunately we have no data whatsoever on Ritalin's transfer to human milk.
But reviewing its kinetics and structure, one is led to the possibility that it
would transfer in significant levels to the infant. First, it is incredibly
lipid soluble, has a high oral bioavailability(95%), a high pKa(8.8), and a
huge volume of distribution (11-33 l/kg). So I would suspect that it may
transfer in high enough levels to effect a breastfed infant. What would you
see...stimulation, anorexia, weight loss, jitteryness, etc. Risk assessment
may exclude this drug, but I don't really know this for certain. Just be
cautious.
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To : Jay Simpson
Re : Zafirlukast (Accolate)
From my next edition:
Zafirlukast is a new competitive receptor antagonist of leukotriene D4 and
other components of slow-reacting substance of anaphylaxis which are mediators
of bronchconstriction in asthmatic patients. Zafirlukast is not a
bronchodilator and should not be used for acute asthma attacks. Zafirlukast is
excreted into milk in low concentrations. Following repeated 40 mg doses twice
daily (please note: average adult dose is 20 mg twice daily), the average
steady-state concentration in breastmilk was 50 ng/mL (50 µg/L) compared to
255 ng/mL in maternal plasma. Zafirlukast is poorly absorbed when administered
with food. It is likely the oral absorption via ingestion of breastmilk would
be low. The manufacturer recommends against using in breastfeeding mothers.
Pregnancy Risk Category: B
Adult Concerns: Pharyngitis, aggravation reaction, headache, nausea, diarrhea
have been reported.
Pediatric Concerns: None reported.
Drug Interactions: Erythromycin reduces oral bioavailability of zafirlukast by
40%. Aspirin increase zafirlukast plasma levels by 45%. Theophylline
reduces zafirlukast plasma levels by 30%. Zafirlukast increase warfarin
anticoagulation by 35%. Terfenadine reduces zafirlukast plasma levels by 54%.
AHL = 10-13 hours M/P = 0.15
PHL = PB = >99%
PK = 3 hours Oral = Poor
MW = 575 pKa =
Vd =
**************************************************
To :Debby Saalfeld
Re :Niacin
Niacin is an old remedy for hyperlipoproteinemia associated with elevated
cholesterol (Phenotype IIa or b). As such its use has dramatically fallen with
the advent of the new HMG CoA reductase inhibitors (Mevacor, Pravastatin,
etc.). To be efficacous, it's dose must be high, about 2-3 gms/day. Because
niacin produces really nasty flushing and pruritis(itching) one must gently
start at low doses and gradually build up over weeks to a dose of approximately
2 gms/day.
Although it seems to reduce plasma cholesterol by as much as 15-25%, its side
effect profile is high and most patients do not stay on it. Side effects
include elevated liver enzymes, pruritis, flushing, etc. You should monitor
liver function throughout therapy with this product at these doses.
Niacin is directly transferred into human milk in levels proportionate to the
oral intake, which is troublesome when doses of 2-3 gm/day are employed.
Would this be toxic to a newborn, whose liver is immature, possibly, I do not
know.
In treating hypercholesterolemia in breastfeeding mothers, I always go back to
the risk verses benefit question. Hypercholesterolemia and atherosclerosis are
generally not ACUTE problems (at least in most patients), as atherosclerosis
takes a lifetime (many years) to occur. It is my personal belief, that it is
more important to breastfeed this infant than to treat the mom's elevated
cholesterol. After she quits breastfeeding, she can then undergo treatment if
she has all the required risk factors. 6 months to one year probably won't
matter one way or the other. Please take these comments with proper
perspective, they solely depend on the risk factors of the mom, her current
physical status, blood pressure, etc, etc.
Regards
Tom Hale, Ph.D.
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