The Basics
What is Trimethoprim-Sulfamethoxazole?
Used to treat infections such as urinary tract infections, middle ear infections (otitis media), bronchitis, traveler’s diarrhea, and shigellosis (bacillary dysentery).
Brand names for Trimethoprim-Sulfamethoxazole
Bactrim
How Trimethoprim-Sulfamethoxazole is classified
Anti-Infective Agents, Anti-Infective Agents – Urinary, Antibacterial Agents, Folic Acid Antagonists, Sulfonamides
Trimethoprim-Sulfamethoxazole During Pregnancy
Trimethoprim-Sulfamethoxazole pregnancy category
Category CNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.
What we know about taking Trimethoprim-Sulfamethoxazole while pregnant
N/A
Taking Trimethoprim-Sulfamethoxazole While Breastfeeding
What are recommendations for lactation if you're taking Trimethoprim-Sulfamethoxazole?
With healthy, fullterm infants it appears acceptable to use sulfamethoxazole and trimethoprim during breastfeeding after the newborn period. The time of greatest risk for hemolysis in fullterm newborns without glucose-6-phosphate dehydrogenase (G6PD) deficiency might be as short as 8 days after birth.[1] Until further data are accumulated, alternate agents should probably be used in jaundiced, ill, stressed or premature infants, because of the risk of bilirubin displacement and kernicterus. Sulfamethoxazole and trimethoprim should be avoided while breastfeeding a G6PD-deficient infant.[2][3]
Maternal / infant drug levels
With healthy, fullterm infants it appears acceptable to use sulfamethoxazole and trimethoprim during breastfeeding after the newborn period. The time of greatest risk for hemolysis in fullterm newborns without glucose-6-phosphate dehydrogenase (G6PD) deficiency might be as short as 8 days after birth.[1] Until further data are accumulated, alternate agents should probably be used in jaundiced, ill, stressed or premature infants, because of the risk of bilirubin displacement and kernicterus. Sulfamethoxazole and trimethoprim should be avoided while breastfeeding a G6PD-deficient infant.[2][3]
Possible effects of Trimethoprim-Sulfamethoxazole on milk supply
Relevant published information was not found as of the revision date.
Possible alternatives to Trimethoprim-Sulfamethoxazole
List of References
Lactation sources: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501922/1. Zao J, Koren G, Bozzo P. Using nitrofurantoin while breastfeeding a newborn. Can Fam Physician. 2014;60:539-40. PMID: 24925943
2. Chung AM, Reed MD, Blumer JL. Antibiotics and breast-feeding: a critical review of the literature. Paediatr Drugs. 2002;4:817-37. PMID: 12431134
3. Farahnik B, Murase JE. Antibiotic safety considerations in methicillin-resistant Staphylococcus aureus postpartum mastitis. J Am Acad Dermatol. 2016;75:e149. PMID: 27646759
4. Arnauld R, Soutoul JH, Gallier J et al. [Study on the passage of trimethoprim into mother’s milk]. Ouest Med. 1972;25:959-64.
5. Borderon E, Soutoul JH, Borderon JC et al. [Excretion of antibiotics in human milk]. Med Mal Infect. 1975;5:373-6.
6. Miller RD, Salter AJ. The passage of trimethoprim/sulfamethoxazole into breast milk and its significance. In, Daikos CK, ed. Progress in Chemotherapy. Antibacterial chemotherapy. 1974;1:687-91.
7. Forna F, McConnell M, Kitabire FN et al. Systematic review of the safety of trimethoprim-sulfamethoxazole for prophylaxis in HIV-infected pregnant women: Implications for resource-limited settings. AIDS Rev. 2006;8:24-36. PMID: 16736949
8. Ito S, Blajchman A, Stephenson M et al. Prospective follow-up of adverse reactions in breast-fed infants exposed to maternal medication. Am J Obstet Gynecol. 1993;168:1393-9. PMID: 8498418
Disclaimer: This material is provided for educational purposes only and is not intended for medical advice, diagnosis, or treatment. Consult your healthcare provider with any questions.
