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Drug Interactions between Bethaprim Pediatric and carbamazepine

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

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Interactions between your drugs

Moderate

carBAMazepine trimethoprim

Applies to: carbamazepine and Bethaprim Pediatric (sulfamethoxazole / trimethoprim)

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

carBAMazepine food

Applies to: carbamazepine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of carbamazepine. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

In a small, randomized, crossover study, the administration of carbamazepine with grapefruit juice (compared to water) increased plasma drug concentrations by approximately 40%. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits.

MANAGEMENT: Patients receiving carbamazepine should be advised to avoid or limit consumption of alcohol. Given the drug's narrow therapeutic index, patients receiving carbamazepine therapy should preferably avoid the regular consumption of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels. Patients should be advised to report signs of carbamazepine toxicity (nausea, visual disturbances, dizziness, or ataxia) to their physicians.

References

  1. "Product Information. Tegretol (carbamazepine)." Novartis Pharmaceuticals PROD (2002):
  2. Garg SK, Kumar N, Bhargava VK, Prabhakar SK "Effect of grapefruit juice on carbamazepine bioavailability in patients with epilepsy." Clin Pharmacol Ther 64 (1998): 286-8
  3. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther 68 (2000): 468-77

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Moderate

sulfamethoxazole food

Applies to: Bethaprim Pediatric (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.

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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