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Drug Interactions between Bethaprim and st. john's wort

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

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Interactions between your drugs

Moderate

trimethoprim St. John's wort

Applies to: Bethaprim (sulfamethoxazole / trimethoprim) and st. john's wort

MONITOR: Coadministration with potent inducers of CYP450 2C9 and 3A4 may decrease the plasma concentrations of sulfamethoxazole and trimethoprim. A small amount of sulfamethoxazole is metabolized by CYP450 2C9, while trimethoprim is partially metabolized by both CYP450 2C9 and 3A4. In a study of 10 HIV-infected patients receiving sulfamethoxazole-trimethoprim prophylaxis (800 mg-160 mg orally once a day) for at least one month, antituberculosis therapy containing rifampin (600 mg/day) given for more than 12 days decreased mean sulfamethoxazole systemic exposure (AUC) by 23% and mean trimethoprim AUC by 47%, most likely due to induction of hepatic microsomal enzymes by rifampin. The clinical significance of this interaction is unknown, but may be greater with low dosages of sulfamethoxazole-trimethoprim. A case-control study evaluating the effect of sulfamethoxazole-trimethoprim dosage on the risk of toxoplasmosis suggest that rifampin exposure may reduce the efficacy of sulfamethoxazole-trimethoprim prophylaxis. Other potent CYP450 inducers may interact similarly.

MANAGEMENT: The potential for diminished pharmacologic effects of sulfamethoxazole-trimethoprim should be considered during coadministration with potent CYP450 2C9 and 3A4 inducers, particularly when sulfamethoxazole-trimethoprim is used for prevention of toxoplasmic encephalitis in HIV patients because adequate drug levels are required in the central nervous system. It may be advisable to refrain from low-dose prophylactic regimens (less than 4 DS tablets per week). Alternative treatments may be required if an interaction is suspected.

References

  1. Bhatia RS, Uppal R, Malhi R, Behera D, Jindal SK "Drug interaction between rifampicin and cotrimazole in patients with tuberculosis." Hum Exp Toxicol 10 (1991): 419-21
  2. Ribera E, FernandezSola A, Juste C, Rovira A, Romero FJ, ArmadansGil L, Ruiz I, Ocana I, Pahissa A "Comparison of high and low doses of trimethoprim-sulfamethoxazole for primary prevention of toxoplasmic encephalitis in human immunodeficiency virus-infected patients." Clin Infect Dis 29 (1999): 1461-6
  3. Ribera E, Pou L, Fernandez-Sola A, et al. "Rifampin reduces concentrations of trimethoprim and sulfamethoxazole in serum in human immunodeficiency virus-infected patients." Antimicrob Agents Chemother 45 (2001): 3238-41

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Drug and food interactions

Moderate

St. John's wort food

Applies to: st. john's wort

GENERALLY AVOID: An isolated case report suggests that foods containing large amounts of tyramine may precipitate a hypertensive crisis in patients treated with St. John's wort. The mechanism of interaction is unknown, as St. John's wort is not thought to possess monoamine oxidase (MAO) inhibiting activity at concentrations achieved in vivo. The case patient was a 41-year-old man who had been taking St. John's wort for seven days prior to presentation at the emergency room with confusion and disorientation. The patient recalled last eating aged cheese and having a glass of red wine approximately 10 hours prior to admission. No other cause of delirium or hypertension could be identified. In addition, alcohol may potentiate some of the pharmacologic effects of St. John's wort. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Until further information is available, patients treated with St. John's wort should consider avoiding consumption of protein foods in which aging or breakdown of protein is used to increase flavor. These foods include cheese (particularly strong, aged or processed cheeses), sour cream, wine (particularly red wine), champagne, beer, pickled herring, anchovies, caviar, shrimp paste, liver (particularly chicken liver), dry sausage, figs, raisins, bananas, avocados, chocolate, soy sauce, bean curd, yogurt, papaya products, meat tenderizers, fava beans, protein extracts, and dietary supplements. Caffeine may also precipitate hypertensive crisis so its intake should be minimized as well. Patients should also be advised to avoid or limit consumption of alcohol.

References

  1. Patel S, Robinson R, Burk M "Hypertensive crisis associated with St. John's Wort." Am J Med 112 (2002): 507-8

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Moderate

sulfamethoxazole food

Applies to: Bethaprim (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

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

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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

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