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Drug Interactions between azathioprine and sulfamethoxazole / trimethoprim

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

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Interactions between your drugs

Moderate

azaTHIOprine trimethoprim

Applies to: azathioprine and sulfamethoxazole / trimethoprim

MONITOR: Even though the combination is used in clinical practice, the risk of bone marrow suppression may be increased when azathioprine or mercaptopurine is coadministered with trimethoprim or sulfamethoxazole-trimethoprim (co-trimoxazole). The risk may be increased when concurrent therapy is longer than 3 weeks. Thrombocytopenia and neutropenia have been reported; however, data have been conflicting. The mechanism is unknown, but may be related to additive myelosuppressive effects and hemodialysis-induced folate depletion.

MANAGEMENT: Close clinical and laboratory monitoring for the development of hematologic adverse effects is recommended both during and after discontinuation of therapy. Dosage adjustment of azathioprine or mercaptopurine may be considered if an interaction is suspected. Patients should be advised to promptly report symptoms such as chills, fever, malaise, sore throat, mouth sores, unusual fatigue, bruising, or bleeding.

References (6)
  1. Berg KJ, Gjellestad A, Nordby G, et al. (1989) "Renal effects of trimethoprim in ciclosporin- and azathioprine-treated kidney-allografted patients." Nephron, 53, p. 218-22
  2. Bailey RR (1984) "Leukopenia due to a trimethoprim-azathioprine interaction." N Z Med J, 97, p. 739
  3. (2002) "Product Information. Imuran (azathioprine)." Glaxo Wellcome
  4. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  5. Canadian Pharmacists Association (2006) e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink
  6. Cerner Multum, Inc. "Australian Product Information."

Drug and food interactions

Moderate

sulfamethoxazole food

Applies to: sulfamethoxazole / trimethoprim

MONITOR: Two cases have been reported in which patients on sulfamethoxazole-trimethoprim therapy, after consuming beer, reported flushing, heart palpitations, dyspnea, headache, and nausea (disulfiram - alcohol type reactions). First-generation sulfonylureas have been reported to cause facial flushing when administered with alcohol by inhibiting acetaldehyde dehydrogenase and subsequently causing acetaldehyde accumulation. Since sulfamethoxazole is chemically related to first-generation sulfonylureas, a disulfiram-like reaction with products containing sulfamethoxazole is theoretically possible. However, pharmacokinetic/pharmacodynamic data are lacking and in addition, the two reported cases cannot be clearly attributed to the concomitant use of sulfamethoxazole-trimethoprim and alcohol.

MANAGEMENT: Patients should be alerted to the potential for this interaction and although the risk for this interaction is minimal, caution is recommended while taking sulfamethoxazole-trimethoprim concomitantly with alcohol.

References (2)
  1. Heelon MW, White M (1998) "Disulfiram-cotrimoxazole reaction." Pharmacotherapy, 18, p. 869-70
  2. Mergenhagen KA, Wattengel BA, Skelly MK, Clark CM, Russo TA (2020) "Fact versus fiction: a review of the evidence behind alcohol and antibiotic interactions." Antimicrob Agents Chemother, 64, e02167-19

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.

See also

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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

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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