Acetaminophen / aspirin Pregnancy and Breastfeeding Warnings
Acetaminophen / aspirin Pregnancy Warnings
Acetaminophen 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 should only be given during pregnancy when need has been clearly established. Aspirin has not been formally assigned to pregnancy category by the FDA. However, aspirin is considered to be in pregnancy category D by the FDA if full dose aspirin is taken in the third trimester. Use of nonsteroidal anti-inflammatory drugs during the third trimester of pregnancy should be avoided due to effects on the fetal cardiovascular system (closure of the ductus arteriosus). Aspirin use in pregnancy has been associated with alterations in both maternal and fetal hemostasis. In addition, high doses have been associated with increased perinatal mortality, intrauterine growth retardation, and teratogenic effects. During the first two trimesters of pregnancy, aspirin should only be given during pregnancy when clearly needed and when benefit outweighs risk. In 1990, the FDA issued a warning that it is especially important not to use aspirin during the last trimester of pregnancy unless specifically directed to do so by a physician because it may cause problems in the unborn child or complications during delivery.
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. Increased maternal bleeding can occur during delivery when aspirin is used 1 week prior to and/or during labor and delivery. Prolonged gestation and labor have been reported due to aspirin's inhibition of prostaglandin. A study of the use of low-dose aspirin (60 mg per day) to prevent and treat preeclampsia in 9364 pregnant women (the Collaborative Low-dose Aspirin Study in Pregnancy--CLASP) did "not support routine prophylactic or therapeutic administration of antiplatelet therapy in pregnancy to all women at increased risk of preeclampsia or IUGR." In that study, no excess of intraventricular hemorrhage, neonatal bleeds, or mortality attributable to bleeding were observed. The investigators did identify a possible role for low-dose aspirin in the treatment of early- onset preeclampsia severe enough to need very preterm delivery. Another study of low-dose aspirin (follow-up from the Italian Study of Aspirin in Pregnancy) has suggested that "low dose aspirin in pregnancy is safe with respect to the risks of malformation and of major impairment in development at 18 months of age." High-dose aspirin (2 g per day) has been associated with stillbirths, cerebral hemorrhage, oculoauriculovertebral dysplasia, neonatal salicylate toxicity, constricted ductus arteriosus, cyclopia, and neonatal acidosis. Some cases of congenital heart defects have been reported. However, a case control study of aspirin use in the first trimester concluded that aspirin "does not increase the risk of congenital heart defects in relation to that of other structural malformations."
Acetaminophen / aspirin Breastfeeding Warnings
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.
Acetaminophen is excreted into human milk in small concentrations. 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. Aspirin is excreted into human milk in small amounts. Peak milk salicylate levels have been reported at nine hours after maternal dosing (and measured at 1.1 mg/dL). Use of large doses of aspirin can result in rashes, platelet abnormalities, and bleeding in nursing infants. Because of a single case report of metabolic acidosis, the American Academy of Pediatrics characterizes aspirin as a drug that has been "associated with significant effects on some nursing infants and should be given to nursing mothers with caution."
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