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Valacyclovir Disease Interactions

There are 4 disease interactions with valacyclovir:

Moderate

Valacyclovir (applies to valacyclovir) dehydration

Moderate Potential Hazard, Moderate plausibility.

Valacyclovir is almost completely converted to acyclovir and L-valine by first-pass intestinal and/or hepatic metabolism; acyclovir is primarily eliminated by the kidney. Cases of acute renal failure have been reported in patients without adequate hydration. Acyclovir may precipitate in renal tubules when the solubility (2.5 mg/mL) is exceeded in the intratubular fluid. Adequate hydration should be maintained for all patients. If acute renal failure and anuria occur, patients may benefit from hemodialysis until renal function is restored.

Moderate

Valacyclovir (applies to valacyclovir) hemodialysis

Moderate Potential Hazard, High plausibility.

Valacyclovir is almost completely converted to acyclovir and L-valine by first-pass intestinal and/or hepatic metabolism. About one-third of acyclovir in the body is removed by dialysis during a 4-hour hemodialysis session. The recommended dose of valacyclovir should be administered after hemodialysis.

References

  1. Laskin OL, Longstreth JA, Whelton A, et al "Acyclovir kinetics in end-stage renal disease." Clin Pharmacol Ther 31 (1982): 594-600
  2. "Product Information. Valtrex (valacyclovir)." Glaxo Wellcome, Research Triangle Park, NC.
  3. Krasny HC, Liao SH, de Miranda P, Laskin OL, Whelton A, Lietman PS "Influence of hemodialysis on acyclovir pharmacokinetics in patients with chronic renal failure." Am J Med 73 (1982): 202-4
Moderate

Valacyclovir (applies to valacyclovir) renal impairment

Moderate Potential Hazard, High plausibility. Applicable conditions: Renal Dysfunction

Valacyclovir is almost completely converted to acyclovir and L-valine by first-pass intestinal and/or hepatic metabolism; acyclovir is primarily eliminated by the kidney. Cases of acute renal failure and CNS side effects (including agitation, hallucinations, confusion, delirium, seizures, and encephalopathy) have been reported in patients with preexisting renal disease who received higher-than-recommended doses of valacyclovir for their level of renal function. Cases of acute renal failure have also been reported in patients receiving other nephrotoxic agents. Therapy with valacyclovir should be administered cautiously in elderly patients (with or without renal dysfunction) and patients receiving other nephrotoxic agents. Dosage reductions are recommended in patients with renal dysfunction. If acute renal failure and anuria occur, patients may benefit from hemodialysis until renal function is restored; valacyclovir should be discontinued if CNS side effects develop.

References

  1. "Product Information. Valtrex (valacyclovir)." Glaxo Wellcome, Research Triangle Park, NC.
  2. Laskin OL, Longstreth JA, Whelton A, et al "Effect of renal failure on the pharmacokinetics of acyclovir." Am J Med 73 (1982): 197-201
  3. Laskin OL, Longstreth JA, Whelton A, et al "Acyclovir kinetics in end-stage renal disease." Clin Pharmacol Ther 31 (1982): 594-600
Moderate

Valacyclovir (applies to valacyclovir) TTP/HUS

Moderate Potential Hazard, Low plausibility. Applicable conditions: Organ Transplant, Immunodeficiency, Bone Marrow Transplantation, Neutropenia

Thrombotic thrombocytopenic purpura/hemolytic uremia syndrome (TTP/HUS), in some cases resulting in death, has been reported in patients with advanced HIV-1 disease, in allogeneic bone marrow transplant recipients, and in renal transplant recipients during clinical trials of valacyclovir at doses of 8 g/day. Therapy with valacyclovir should be discontinued immediately if clinical signs, symptoms, and laboratory abnormalities consistent with TTP/HUS develop.

References

  1. "Product Information. Valtrex (valacyclovir)." Glaxo Wellcome, Research Triangle Park, NC.

Valacyclovir drug interactions

There are 60 drug interactions with valacyclovir

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.