Trimethoprim Pregnancy and Breastfeeding Warnings
Trimethoprim Pregnancy Warnings
Trimethoprim has been assigned to pregnancy category C by the FDA. Animal studies have revealed evidence of teratogenicity. There are no controlled data in human pregnancy. Trimethoprim should only be given during pregnancy when benefit outweighs risk.
There are no reports of teratogenicity associated with trimethoprim as a single agent. However, the Michigan Medicaid surveillance study demonstrated possible teratogenic effects associated with the combination drug, trimethoprim-sulfamethoxazole (TMP-SMX). This report is a summary of information from two studies, one in which 1,116 of 104,000 pregnant women from 1980 to 1983, and one in which 2,296 of 229,000 pregnant women from 1985 to 1992 received TMP-SMX. In the first study, 83 total defects (13 cardiovascular defects) were observed (14 and 2 were expected, respectively). In the second study, 126 total defects (37 cardiovascular defects) were observed (98 and 27 were expected, respectively). Cleft palate was observed in three cases in the latter study. These data support an association between TMP-SMX and congenital defects, although other causes such as the underlying disease(s) of the mother and concomitant drug therapy are unaccounted for. Moreover, the individual contributions of TMP versus SMX are not known. There has also been a single report of Niikawa-Kuroki syndrome, characterized by mental and growth retardation and craniofacial abnormalities, associated with TMP-SMX.
Trimethoprim Breastfeeding Warnings
The average milk levels obtained after trimethoprim 160 mg twice a day range from 1.8 to 2.0 mcg/mL between two and three hours after dosing. No adverse effects of trimethoprim on nursing infants have been reported.
Trimethoprim is excreted into human milk in small amounts. The risk of interference with folic acid metabolism exists. The combination trimethoprim-sulfamethoxazole is considered compatible with breast-feeding by the American Academy of Pediatrics. The manufacturer recommends caution when trimethoprim is administered to nursing women.
- Trimethoprim use while Breastfeeding (in more detail)
- trimethoprim Consumer Information
- Pregnancy Support Group
- FDA Pregnancy Categories
- Medicine use during Pregnancy
- Medicine use while Breastfeeding
- Safe Medications during Breastfeeding
Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Wolters Kluwer Health and Drugs.com is accurate, up-to-date, and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This drug information does not endorse drugs, diagnose patients, or recommend therapy. This drug information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug of drug combination is safe, effective, or appropriate for any given patient. Multum Information Services, Inc. does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. Copyright 2000-2008 Multum Information Services, Inc. The information in contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.