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Drug Interactions between trimethoprim and valganciclovir

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

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Interactions between your drugs

Minor

trimethoprim valGANciclovir

Applies to: trimethoprim and valganciclovir

The coadministration of ganciclovir or its prodrug, valganciclovir, with trimethoprim may result in elevated plasma concentrations of ganciclovir. In 12 subjects with HIV and CMV coinfection, trimethoprim (200 mg orally once a day) increased the half-life of ganciclovir (1000 mg orally every 8 hours) by an average of 15% and decreased its renal clearance by 16%. The mechanism is unknown but may involve the competitive inhibition of ganciclovir renal tubular secretion by trimethoprim. Ganciclovir had minimal effect on the pharmacokinetics of trimethoprim. This interaction is unlikely to be of clinical significance. . However, the use of ganciclovir with other potentially myelotoxic drugs such as trimethoprim may increase the risk and severity of these adverse events due to additive pharmacodynamic effects. The potential for this effect should be kept in consideration and the patient monitored for hematologic adverse effects.

References (4)
  1. (2002) "Product Information. Cytovene (ganciclovir)." Genentech
  2. (2001) "Product Information. Valcyte (valganciclovir)." Roche Laboratories
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  4. Cerner Multum, Inc. "Australian Product Information."

Drug and food interactions

Moderate

valGANciclovir food

Applies to: valganciclovir

ADJUST DOSING INTERVAL: Food increases the bioavailability of ganciclovir from the prodrug, valganciclovir. In 16 HIV-positive subjects, the administration of valganciclovir 875 mg once daily with a high-fat meal containing approximately 600 calories resulted in a 30% increase in the steady-state area under the plasma concentration-time curve (AUC) and a 14% increase in the peak plasma concentration (Cmax) of ganciclovir, with no delay in the time to reach peak plasma concentration (Tmax). The mechanism is unknown.

MANAGEMENT: The manufacturer recommends that valganciclovir be taken with meals.

References (2)
  1. (2001) "Product Information. Valcyte (valganciclovir)." Roche Laboratories
  2. Brown F, Banken L, Saywell K, Arum I (1999) "Pharmacokinetics of valganciclovir and ganciclovir following multiple oral dosages of valganciclovir in HIV- and CMV-seropositiv volunteers." Clin Pharmacokinet, 37, p. 167-76

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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