To : Linda V.
Re : Antiulcer medications
While it is true that Zantac(ranitidine) and Tagamet(cimetidine) have rather
high milk:plasma ratios, this is a prime example when the absolute amount of
medication transferred to the infant is far far lower than a clinically
relevant dose.
The amount of Zantac and Tagamet reaching the infant is miniscule. But if the
doctor is hesitant, i have enclosed monographs below on Pepcid and Axid that
have good kinetics as far as breastfeeding is concerned. Pepcid is a better
product anyway.
Regards
Tom Hale
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Famotidine Fax # 1182
Trade: Pepcid
Uses: Reduces gastric acid secretion
AAP: Not reviewed
Famotidine is a typical Histamine-2 antagonist that reduces stomach acid
secretion. In one study of 8 lactating women receiving a 40 mg/day dose, the
peak concentration in breast milk was 72 µg/L and occurred at 6 hours
post-dose. The milk:plasma ratios were 0.41, 1.78, and 1.33 at 2, 6, and 24
hours respectively. These levels are apparently much lower than other
histamine H-2 antagonists (ranitidine, cimetidine) and make it a preferred
choice.
Adverse Effects: Headache, constipation, increased liver enzymes
AHL= 2.5-3.5 hours M/P= 0.41-1.78
PHL= PB = 17%
PK = 1-3.5 hours Oral= 40%
References:
1. Courtney TP, Shaw RW, et.al. Excretion of famotidine in breast milk.
Br.J.Clin.Pharmacol. 26:639, 1988.
2. Echizen H & Ishizaki T: Clinical pharmacokinetics of famotidine. Clin
Pharmacokinet 1991; 21:178-194.
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Nizatidine Fax # 1317
Trade: Axid
Uses: Reduces gastric acid secretion
AAP: Not reviewed
Nizatidine is an antisecretory, histamine-2 antagonist that reduces stomach
acid secretion. In one study of 5 lactating women using a dose of 150 mg,
milk levels of nizatidine were directly proportional to circulating maternal
serum levels, yet were very low. Over a 12 hour period 96 up (less than 0.1%
of dose) was secreted into the milk. No effects on infants have been
reported.
Adverse Effects: Headache, GI distress
AHL= 1.5 hours M/P=
PHL= PB = 35%
PK = 0.5-3 hours Oral= 94%
References:
1. Obermeyer BD, Bergstrom RF, Callaghan JT, et.al. Secretion of
nizatidine into human breast milk after single and multiple doses.
Clin.Pharmacol.Ther. 47:724-30,1990.
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