Diphenhydramine (Benadryl®)
SUMMARY: Diphenhydramine is considered safe for use in pregnancy when used at the recommended dosage.
Antihistamine. Molecular weight:255.36
CATEGORY: B
Diphenhydramine may cause uterine irritability or
contractions near term when used in high doses (greater than 50mg) [1,2]
In 1974 Saxen reported that a study group of 599 infants with oral clefting were more likely to have been exposed to
diphenhydramine during the first trimester than a control group of infants
without clefting [3]. Subsequent retrospective studies of more than 2300 infants
have found no association between first trimester exposure to
diphenhydramine and oral clefting or major malformations [4-6]
Stillbirth has been reported following the use of diphenhydramine and temazepam during human pregnancy.
The toxicity of this combination was confirmed in pregnant rabbits [7].
BREAST FEEDING: The manufacturer considers diphenhydramine to be contraindicated during
breast feeding.
NEONATAL SIDE EFFECTS: Potential for severe sedation if administered to the
mother before delivery [8].
SEARCH LITERATURE
1. Hara GS et al. J Kans Med Soc. 1980;81:134-6,155.
MEDLINE
2. Brost BC, Diphenhydramine overdose during pregnancy: lessons from the
past. Am J Obstet Gynecol. 1996;175:1376-7.
MEDLINE
3. Saxen I: Cleft palate and maternal diphenhydramine intake. [Letter] Lancet.
1974;1:407-8.
MEDLINE
4. Heinonen OP et al.: Birth Defects and Drugs in Pregnancy, Littleton
Publishing Sciences Group, 1977, pp 322-7.
5. Aselton P et al. First-trimester drug use and congenital disorders. Obstet Gynecol.1985;65:451-5.
MEDLINE
6. Briggs GG,Freeman RK, Yaffe SJ, Drugs in Pregnancy and Lactation 6th edition,Baltimore, MD:
Williams & Wilkins,2002
p 426.
7. Kargas GA, Perinatal mortality due to interaction of diphenhydramine and
temazepam. [Letter] N Engl J Med. 1985;313:1417-8. MEDLINE
8. Miller AA Diphenhydramine toxicity in a newborn: a case report. J
Perinatol. 2000;20:390-1.
MEDLINE
Created: 11/27/2002
Update: 11/30/2003
Update: 6/26/2007 Mark Curran, M.D. FACOG
