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Drug Interactions between folic acid and trimethoprim

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

trimethoprim folic acid

Applies to: trimethoprim and folic acid

MONITOR: Folate antagonists such as sulfonamides, triamterene, trimethoprim, or pyrimethamine may decrease folic acid serum concentration. The mechanism may be related to inhibition of the enzyme dihydrofolate reductase by the folate antagonists, which converts folic acid into its active tetrahydrofolate form. In addition, it should be noted that folic acid doses greater than 2.5 mg may lead to treatment failure of antifolate antimalarials such as pyrimethamine.

MANAGEMENT: Monitoring of patient response to folic acid supplementation if they are also taking folate antagonists is recommended. This may be especially important for pregnant women taking folic acid to reduce their risk of neural tube defects and in patients with megaloblastic anemia. Folic acid doses greater than 2.5 mg should be avoided in patients receiving pyrimethamine. Patients receiving antifolate antimalarials with folic acid should be monitored for possible treatment failure.

References (11)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. van Eijk AM, Ouma PO, Williamson J, et al. (2008) "Plasma Folate Level and High-Dose Folate Supplementation Predict Sulfadoxine-Pyrimethamine Treatment Failure in Pregnant Women in Western Kenya Who Have Uncomplicated Malaria." J Infect Dis, 198, p. 1550-3
  3. Agencia Española de Medicamentos y Productos Sanitarios Healthcare (2008) Centro de información online de medicamentos de la AEMPS - CIMA. https://cima.aemps.es/cima/publico/home.html
  4. Cerner Multum, Inc (2015) "ANVISA Bulário Eletrônico."
  5. (2017) "Product Information. Folic Acid (folic acid)." Method Pharmaceuticals, LLC
  6. Van Hensbroek MB, Morris-Jones S, Meisner S, et al. (1995) "Iron, but not folic acid, combined with effective antimalarial therapy promotes haematological recovery in African children after acute falciparum malaria." Trans R Soc Trop Med Hyg, 89, p. 672-6
  7. Mulenga M, Malunga P, Bennett S. et.al (2006) "Folic acid treatment of Zambian children with moderate to severe malaria anemia." Am J Trop Med Hyg, 74, p. 986-90
  8. Carter JY, Loolpapit MP, Lema OE, Tome JL, Nagelkerke NJK, Watkins WM (2005) "Reduction of the efficacy of antifolate antimalarial therapy by folic acid supplementation." Am J Trop Med Hyg, 73, p. 166-70
  9. Ouma P, Parise ME, Hamel MJ, et al. (2006) "A randomized controlled trial of folate supplementation when treating malaria in pregnancy with sulfadoxine-pyrimethamine." PLoS Clin Trials, 1, e28
  10. Mbaye A, Richardson K, Balajo B, et al. (2006) "Lack of inhibition of the anti-malarial action of sulfadoxine-pyrimethamine by folic acid supplementation when used for intermittent preventive treatment in Gambian primigravidae." Am J Trop Med Hyg, 74, p. 760-4
  11. Nzila A, Okombo J, Molloy AM (2014) "Impact of folate supplementation on the efficacy of sulfadoxine/pyrimethamine in preventing malaria in pregnancy: the potential of 5-methyl-tetrahydrofolate." J Antimicrob Chemother, 69, p. 323-30

Drug and food interactions

Moderate

folic acid food

Applies to: folic acid

MONITOR: Ethanol may increase folic acid elimination and folic acid absorption is decreased in chronic alcoholics. Excessive alcohol consumption may lead to folate deficiency.

MANAGEMENT: Monitoring of patient response to folic acid supplementation if they also consume alcohol regularly may be recommended.

References (5)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."
  3. Agencia Española de Medicamentos y Productos Sanitarios Healthcare (2008) Centro de información online de medicamentos de la AEMPS - CIMA. https://cima.aemps.es/cima/publico/home.html
  4. Cerner Multum, Inc (2015) "ANVISA Bulário Eletrônico."
  5. (2017) "Product Information. Folic Acid (folic acid)." Method Pharmaceuticals, LLC

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

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