Acetaminophen / pheniramine / phenylephrine Pregnancy and Breastfeeding Warnings

Brand names: Scot-Tussin Original, Theraflu Cold & Sore Throat, Theraflu Flu & Sore Throat, Theraflu Sinus & Cold

Medically reviewed by Drugs.com. Last updated on Aug 2, 2023.

Acetaminophen / pheniramine / phenylephrine Pregnancy Warnings

The manufacturer makes no recommendation regarding use during pregnancy.

US FDA pregnancy category: Not assigned

Comments:
-Acetaminophen is commonly used during pregnancy and has been assumed safe; recent data questions the safety, especially with routine use or varying genetics.
-Routine use of acetaminophen during pregnancy is not advised.
-Phenylephrine is a sympathomimetic used in emergencies to treat hypotension and alleviate eye and ear allergic symptoms.
-Phenylephrine could cause constriction in uterine vessels (that are normally maximally dilated during pregnancy), reducing uterine blood flow, potentially causing fetal hypoxia.
-Phenylephrine may interact with oxytocic or ergot derivatives to cause persistent maternal hypertension; cerebral vessel rupture is possible.
-Sympathomimetic amines are teratogenic in some animal models, but are not suspected to cause human teratogenicity.

Animal studies are not available for the combination product. There are no controlled data in human pregnancy.

Acetaminophen: Routinely used during all stages of pregnancy, it appears safe for short-term use. This drug crosses the placenta.

Pheniramine: A monitoring study including 831 mother-child pairs that had first trimester phenylephrine exposure showed a possible relationship to respiratory malformations and eye/ear defects, but confirmation is needed; 2442 any time pregnancy exposures showed no relationship to congenital malformations. Placental transfer is likely with pheniramine's low molecular weight (about 240).

Phenylephrine: A monitoring study including 1249 mother-child pairs that had first trimester phenylephrine exposure showed an increase in malformation, with association greater with minor defects than major defects (8 eye and ear defects, 6 syndactyly, 4 preauricular skin tags, and 3 clubfoot cases); 4149 any time pregnancy exposures were associated with 15 congenital dislocation of the hip, 6 umbilical hernia, and 4 other musculoskeletal defects. Placental transfer is likely with phenylephrine's low molecular weight (about 167).

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

See references

Acetaminophen / pheniramine / phenylephrine Breastfeeding Warnings

Caution is recommended.

Excreted into human milk: Yes (acetaminophen) /Data not available (pheniramine, phenylephrine)
Excreted into animal milk: Data not available (pheniramine, phenylephrine)

Comments:
-The amount of acetaminophen in breast milk is much less than typical infant doses.
-One study calculated that infants receive about 0.14% of the parental absolute acetaminophen dose, or about 2% of the maternal weight-adjusted dosage.
-The molecular weight of pheniramine (about 240) is low enough for excretion into milk.
-Phenylephrine oral bioavailability is about 40%, making it unlikely an infant would receive large doses from breast milk.
-Phenylephrine may decrease milk production.

See references