Drug treatment of gastrointestinal disease in pregnant women can be difficult, particularly because U.S. Food and Drug Administration classifications are not necessarily based on clinical experience or current literature. The American Gastroenterological Association (AGA) released a position statement on gastrointestinal medication use in pregnant women. The report was published in the July 2006 issue of Gastroenterology.
Treatment of gastrointestinal disease after pregnancy is usually preferred; however, waiting to treat some illnesses (e.g., irritable bowel syndrome [IBS]) could cause adverse outcomes. Because of the risk of adverse effects or teratogenicity, there are numerous medications that should never be taken during pregnancy. These include bismuth (Tritec), castor oil, doxycycline (Vibramycin), methotrexate, ribavirin (Virazole), sodium bicarbonate, tetracycline, and thalidomide (Thalomid). If drug treatment is needed, the AGA recommends using the lowest-risk medications possible, providing the most appropriate and effective dosage for the patient's condition, and evaluating pregnancy stage and possible dosing adjustments when making treatment decisions. It also recommends discussing treatment options with the patient before starting any drug therapy.
If endoscopy with sedation is needed in the third trimester, fetal monitoring may be necessary. For lighter sedation, a typical dose of meperidine (Demerol) seems to provide comfort at low risk, and a small dose of midazolam (Versed) can have a calming effect without causing drowsiness. Low doses of fentanyl (Duragesic) also can be used. Consultation with an anesthesiologist or obstetrician is recommended if deeper sedation is required. When performing colonic lavage, low-risk treatment options include tap water enemas and polyethylene glycol solutions. Bipolar cautery that does not require grounding pad placement should be used for therapeutic interventions.
When treating nausea, vomiting, or hyperemesis gravidarum during pregnancy, low-risk drug options include metoclopramide (Reglan), ondansetron (Zofran), pro-chlorperazine (Compazine), promethazine (Phenergan), and trimethobenzamide (Tigan). For heartburn, first-line treatment is over-the-counter calcium-based antacids. Antacids containing aluminum or magnesium are another low-risk option. Few data are available on the use of famotidine (Pepcid) and nizatidine (Axid) in pregnancy; the use of cimetidine (Tagamet) and ranitidine (Zantac) is preferred. Although omeprazole (Prilosec) has shown some fetal and embryonic toxicity, it is still a drug of choice because the risk remains low.
If hepatitis A or B vaccines are needed during pregnancy, both are considered low risk. For the management of hepatitis C, ribavirin and interferon are not recommended because they are contraindicated in pregnancy. Patients with Wilson's disease who need regular penicillamine (Cuprimine) therapy should have the dosage reduced to 250 mg per day by the third trimester; trientine (Syprine) appears to be a more low-risk option for managing this disease. For cholestasis of pregnancy, ursodiol (Actigall) has been used successfully without increasing adverse events. Because of impaired fetal growth, use of propranolol (Inderal) or any similar class of drugs to treat portal hypertension is not recommended after the first trimester. If a liver transplant is needed, cyclosporine (Sandimmune) and tacrolimus (Prograf) are low-risk options at dosages required for graft survival.
Dietary modifications (e.g., increased fiber intake, reduced fat and dairy consumption) are considered first-line therapy in the treatment of IBS. If medication use is necessary to treat constipation, osmotic laxatives, polyethylene glycol, docusate, senna, bisacodyl, and tegaserod (Zelnorm) are considered low-risk options. For diarrhea, loperamide (Imodium) and diphenoxylate with atropine (Lomotil) are low-risk options, but these agents are not recommended because of their possible fetal toxicity risk. There are no low-risk options for treating abdominal pain.
Although most infectious diarrhea episodes are self-limited, there still are some antibiotic treatment options for use in pregnancy. These include albendazole (Valbazen), ampicillin, vancomycin, azithromycin (Zithromax), furazolidone (Furoxone), tinidazole (Tindamax), and metronidazole (Flagyl). However, physicians should be aware that although these drugs may not cause an increased risk of birth defects, some have the potential to cause other adverse effects (e.g., gastrointestinal distress), and some recommendations are based on limited data. For women with IBS, the most favorable option would be to conceive while in remission. However, 5-aminosalicylates are considered low risk for maintenance of remission during pregnancy.