The FDA system ranks drugs as:
· Category A - drugs that have been tested for safety during pregnancy and have been found to be safe. This includes drugs such as folic acid, vitamin B6, and thyroid medicine in moderation, or in prescribed doses.
· Category B - drugs that have been used a lot during pregnancy and do not appear to cause major birth defects or other problems. This includes drugs such as some antibiotics, acetaminophen (Tylenol), aspartame (artificial sweetener), famotidine (Pepcid), prednisone (cortisone), insulin (for diabetes), and ibuprofin (Advil, Motrin) before the third trimester. Pregnant women should not take ibuprofen during the last three months of pregnancy.
· Category C - drugs that are more likely to cause problems for the mother or foetus. Also includes drugs for which safety studies have not been finished. The majority of these drugs do not have safety studies in progress. These drugs often come with a warning that they should be used only if the benefits of taking them outweigh the risks. This is something a woman would need to carefully discuss with her doctor. These drugs include prochlorperzaine (Compazine), Sudafed, fluconazole (Diflucan), and ciprofloxacin (Cipro). Some antidepressants are also included in this group.
· Category D - drugs that have clear health risks for the foetus and include alcohol, lithium (used to treat manic depression), phenytoin (Dilantin), and most chemotherapy drugs to treat cancer. In some cases, chemotherapy drugs are given during pregnancy.
Category X - drugs that have been shown to cause birth defects and
should never be taken during pregnancy. This includes drugs to treat skin
conditions like cystic acne (Accutane) and psoriasis
(Tegison or Soriatane); a
sedative (thalidomide); and a drug to prevent miscarriage used up until 1971 in
Most medications, though, have not been
studied or shown to be safe to this extent. For these, we are left with this
guideline: Medications that are considered safe in pregnancy are those that
have been used extensively in humans and don't appear to cause any major
birth defects or other problems (they also have been shown not to cause birth
defects in animals). The FDA classifies these drugs as Category B. Treatment
with Category B medications is considered "probably safe." This group
includes ampicillin, acetaminophen (Tylenol is a
common brand), ibuprofen (such as Motrin) before third trimester, aspartame,
caffeine in moderation, hydrochlorothiazide (HCTZ), metoclopramide
(Reglan), famotidine (Pepcid), loperamide (Imodium),
Anti-histamines. Older anti-histamines, such as chlorpheniramine and tripelennamine, are the preferred agents to treat allergic rhinitis during pregnancy, and are both category B medications. Newer anti-histamines such as over-the-counter loratadine (Claritin®/Alavert® and generic forms) and prescription cetirizine (Zyrtec®) are also pregnancy category B medications.
Decongestants. Pseudoephedrine (Sudafed®, many generic forms) is the preferred oral decongestant to treat allergic and non-allergic rhinitis during pregnancy, although should be avoided during the entire first trimester, as it has been associated with infant gastroschisis. This medication is pregnancy category C.
Medicated nasal sprays. Cromolyn nasal spray (NasalCrom®, generics) is helpful in treating allergic rhinitis if it is used before exposure to an allergen and prior to the onset of symptoms. This medication is pregnancy category B and is available over-the-counter. If this medication is not helpful, one nasal steroid, budesonide (Rhinocort Aqua®), recently received a pregnancy category B rating (all others are category C), and therefore would be the nasal steroid of choice during pregnancy.
Immunotherapy. Allergy shots can be continued during pregnancy, but it is not recommended to start this treatment while pregnant. Typically the dose of the allergy shots is not increased, and many allergists will cut the dose of the allergy shot by 50% during pregnancy. Some allergists feel that allergy shots should be stopped during pregnancy, given the risk of anaphylaxis and possible danger to the fetus as a result. Other than anaphylaxis, there is no data showing that the allergy shots themselves are actually harmful to the fetus.
Category A: Controlled studies in pregnant women demonstrate no fetal risk (eg, folic acid, levothyroxine);
Category B: Controlled animal studies have not shown a fetal risk but there are no studies done on women OR controlled studies in animals have shown a fetal risk that was not reproduced in controlled human studies (eg, amoxicillin, ceftriaxone);
Category C: Controlled animal studies have demonstrated adverse fetal effects and there are no human studies or there are no controlled studies in humans or animals (eg, nifedipine, omeprazole);
Category D: Controlled studies in humans demonstrate adverse fetal effects but the benefits of using the drug are greater than the risks (eg, propylthiouracil); and
Category X: Controlled studies in animals and humans have demonstrated adverse fetal effects or there is evidence of fetal risk based on human experience. The risk of using these drugs outweighs any possible benefit. The drug is absolutely contraindicated in pregnancy (eg, misoprostol, warfarin, isotretinoin).