Acetaminophen Pregnancy and Breastfeeding Warnings
Acetaminophen is also known as: Acephen, Aceta, Altenol, Arthritis Pain Relief, Bydol, Children's Tylenol, Dafalgan, Doliprane, Efferalgan, Infant's Tylenol, Lemsip Max, Mapap, Ofirmev, Panadol, Panadol ActiFast, Panadol Osteo, Paracetamol, Perfalgan, Pharbetol, Q-Pap, Taminol, Tempra, Tylenol, Tylenol Arthritis Pain, Tylenol Extra Strength
Acetaminophen Pregnancy Warnings
Two cases of acetaminophen overdose in late pregnancy have been reported. In both cases neither the neonate nor the mother suffered hepatic toxicity. Investigations have revealed conflicting results with regards to the pharmacokinetic disposition of acetaminophen in pregnant women. One study has suggested that the oral clearance of acetaminophen is 58% higher and the elimination half-life is 28% longer in pregnant women compared to nonpregnant women. Another study has suggested that the elimination half-life is not different in patients who are pregnant. That study also suggested that the volume of distribution of acetaminophen may be higher in pregnant women. One study has suggested that acetaminophen in typical oral doses may result in a reduced production of prostacyclin in pregnant women. That study also suggested that acetaminophen does not affect thromboxane production.
Acetaminophen in oral or rectal form has not been formally assigned to a pregnancy category by the FDA. It is routinely used for short-term pain relief and fever in all stages of pregnancy. Acetaminophen is believed to be safe in pregnancy when used intermittently for short durations. Acetaminophen oral or rectal should only be given during pregnancy when need has been clearly established. Acetaminophen in IV form has been assigned to FDA pregnancy category C. There are no studies of intravenous acetaminophen in pregnant women; however, epidemiological data on oral acetaminophen use in pregnant women show no increased risk of major congenital malformations. Animal reproduction studies have not been conducted with acetaminophen, and it is not known whether IV acetaminophen can cause fetal harm when administered to a pregnant woman. IV acetaminophen should be given to a pregnant woman only if clearly needed.
Acetaminophen Breastfeeding Warnings
Oral acetaminophen is excreted into human milk in small concentrations. Studies with acetaminophen IV have not been conducted. Based on data from more than 15 nursing mothers, the calculated infant daily dose of acetaminophen is approximately 1 to 2% of the maternal dose. One case of a rash has been reported in a nursing infant. Acetaminophen is considered compatible with breast-feeding by the American Academy of Pediatrics. The manufacturer recommends caution when administering acetaminophen in IV form to a nursing mother.
One small study has reported that following a 1000 mg dose of acetaminophen to nursing mothers, nursing infants receive less than 1.85% of the weight-adjusted maternal oral dose.
References for pregnancy information
- Galinsky RE, Levy G "Absorption and metabolism of acetaminophen shortly before parturition." Drug Intell Clin Pharm 18 (1984): 977-9
- O'Brien WF, Krammer J, O'Leary TD, Mastrogiannis DS "The effect of acetaminophen on prostacyclin production in pregnant women." Am J Obstet Gynecol 168 (1993): 1164-9
- Levy G, Garrettson LK, Soda DM "Evidence of placental transfer of acetaminophen." Pediatrics 55 (1975): 895
- Roberts I, Robinson MJ, Mughal MZ, Ratcliffe JG, Prescott LF "Paracetamol metabolites in the neonate following maternal overdose." Br J Clin Pharmacol 18 (1984): 201-6
- Beaulac-Baillargeon L, Rocheleau S "Paracetamol pharmacokinetics during the first trimester of human pregnancy." Eur J Clin Pharmacol 46 (1994): 451-4
- Byer AJ, Traylor TR, Semmer JR "Acetaminophen overdose in the third trimester of pregnancy." JAMA 247 (1982): 3114-5
- Rayburn W, Shukla U, Stetson P, Piehl E "Acetaminophen pharmacokinetics: comparison between pregnant and nonpregnant women." Am J Obstet Gynecol 155 (1986): 1353-6
- Rudolph AM "Effects of aspirin and acetaminophen in pregnancy and in the newborn." Arch Intern Med 141 (1981): 358-63
- Miners JO, Robson RA, Birkett DJ "Paracetamol metabolism in pregnancy." Br J Clin Pharmacol 22 (1986): 359-62
References for breastfeeding information
- Findlay JW, DeAngelis RL, Kearney MF, et al "Analgesic drugs in breast milk and plasma." Clin Pharmacol Ther 29 (1981): 625-33
- Notarianni LJ, Oldham HG, Bennett PN "Passage of paracetamol into breast milk and its subsequent metabolism by the neonate." Br J Clin Pharmacol 24 (1987): 63-7
- Committee on Drugs, 1992 to 1993 "The transfer of drugs and other chemicals into human milk." Pediatrics 93 (1994): 137-50
- Matheson I, Lunde PK, Notarianni L "Infant rash caused by paracetamol in breast milk." Pediatrics 76 (1985): 651-2
- Roberts RJ, Blumer JL, Gorman RL, et al "American Academy of Pediatrics Committee on Drugs: Transfer of drugs and other chemicals into human milk." Pediatrics 84 (1989): 924-36
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