Fatal Flaw in the Folate Pathway: Methotrexate-Bactrim Interaction, Misleading Levels, and a Cautionary Case.
Case Reports
Names both Trimethoprim-Sulfamethoxazole and Vitamin B9 in its title.
Supplement × Prescription·Evidence index
PubMed indexes 7 records that name Trimethoprim-Sulfamethoxazole and Vitamin B9 together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.
Every statement below is attributed to a named, dated, linked source.
This page lists published research relevant to Trimethoprim-Sulfamethoxazole and Vitamin B9. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.
Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.
Names both Trimethoprim-Sulfamethoxazole and Vitamin B9 in its title.
Names both Trimethoprim-Sulfamethoxazole and Vitamin B9 in its title.
“Gel shift assays confirmed that LsrR, the AI-2 receptor, did not bind to the promoters of folA and folC, suggesting that exogenous AI-2 might influence folate metabolism by a feedback inhibition effect but not in the LsrR-dependent pathway. This study might provide further information in the search for potential drug targets for prophylaxis of avian colibacillosis and for auxiliary antibiotics in the treatment of avian colibacillosis.”
Names both Trimethoprim-Sulfamethoxazole and Vitamin B9 in its title.
“The data showed the adverse effects of co-trimoxazole on the ovarian maturational status and tissue structure which was reversed partially by folic acid co-administration in rats.”
Names both Trimethoprim-Sulfamethoxazole and Vitamin B9 in its title.
Names both Trimethoprim-Sulfamethoxazole and Vitamin B9 in its title.
“Endocrine dysfunctions (thyroid, adrenal, and pituitary disorders) and toxic ingestions are medical disorders known to cause brief psychotic episodes. Fluoroquinolones, penicillins, and trimethoprim-sulfamethoxazole are common antibiotics associated with this rare adverse effect.”
Names Trimethoprim-Sulfamethoxazole and Vitamin B9 together in an interaction, co-administration, or pharmacokinetic context.
Names Trimethoprim-Sulfamethoxazole and Vitamin B9 together in an interaction, co-administration, or pharmacokinetic context.
Search-based evidence indexes have real limits, and it is worth being explicit about them:
NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Trimethoprim-Sulfamethoxazole, Vitamin B9, and several hundred other substances.
The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.
NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.