Pregnancy Categories

Question 1

Which category refers to drugs where there are adequate, well-controlled studies in pregnant women that have not shown an increased risk of fetal abnormalities to the fetus in any trimester of the pregnancy? Examples?

Answer 1

Category A

Folic acid, B6, levothyroxine

Question 2

Which category refers to drugs that have animal studies that have revealed no evidence of harm to the fetus, but have no adequate and well controlled studies in pregnant women OR animal studies have shown an AE but adequate, well-controlled studies in pregnant have failed to show the same risk to the fetus in any trimester? Examples?

Answer 2

Category B
APAP, prednisone, insulin, amoxicillin, cetirizine (zyrtec), loratidine

Ex- Zyrtec was teratogenic in animals at 40-220x the max recommended dose

Question 3

What describes Category C drugs like prochlorperazine, many antidepressants, ciprofloxacin, and fluconazole?

Answer 3

Animal studies have shown AE and there are no adequate, well-controlled trials in pregnant women OR no animals studies have been conducted and no adequate, well controlled studies in pregnant women

Question 4

Which class has adequate well-controlled or observational studies in pregnant women that have demonstrated a risk to the fetus BUT the benefits of therapy may outweigh the potential risk?

Answer 4

Category D

Lithium, phenytoin, valproic acid, carbmazepine, tetracyclines, ACEI, most chemotherapy

Question 5

Which category constitutes the the absolute contraindication of use during pregnancy?

Answer 5

Category X (adequate well-controlled or observational studies in animals or pregnant women have demonstrated positive evidence of fetal risk)

Ex- Accutane, thalidomide, misoprostil (Cytotec)

Question 6

How is NSAID use risk related to trimester?

Answer 6

Category C drug late in pregnancy d/t risk of premature closure of the ductus arteriosus

Question 7

How should patients taking Efavirenz (Sustiva) for treatment of HIV be counseling about pregnancy?

Answer 7

Drug is a Cat D drug in the 1st trimester (during organ development).
It has a long half-life of >40hrs so should be discontinued 12weeks before trying to become pregnant

Question 8

Why is TMP/SMX (Bactrim) a Category D drug during the 1st trimester?

Answer 8

Due to its interference with folic acid metabolism

Update to categories has made Bactrim a Cat D drug throughout pregnancy-used to be Cat C

Question 9

Which categories are most helpful to prescribers?

Answer 9

Cat A and Cat X