Contraindications
1.Valganciclovir hydrochloride tablets are contraindicated in patients with known hypersensitivity to valganciclovir, ganciclovir, or any other excipient in the formulation.
2.Due to the similar chemical structures of valganciclovir hydrochloride, acyclovir, and valacyclovir, cross‑hypersensitivity reactions may occur among these drugs.
Warnings
1.In animal studies, ganciclovir was found to be mutagenic, teratogenic, azoospermic, and carcinogenic. Therefore, valganciclovir hydrochloride tablets are considered potentially teratogenic and carcinogenic in humans and may cause congenital defects and tumors (see Storage and Handling). Valganciclovir hydrochloride tablets are also considered to cause temporary or permanent inhibition of spermatogenesis (see Preclinical Safety Data, Pregnancy, and Adverse Reactions).
2.Severe leukopenia, neutropenia, anemia, thrombocytopenia, pancytopenia, myelosuppression, and aplastic anemia have been reported in patients treated with valganciclovir hydrochloride tablets (or ganciclovir). Treatment should not be initiated if the absolute neutrophil count is less than 500 cells/mL, platelet count less than 25,000 cells/mL, or hemoglobin less than 8 g/dL (see Dosage Adjustment Guidelines, Precautions, and Adverse Reactions).
3.Use of valganciclovir hydrochloride tablets in pediatric patients is not recommended (see Special Dosage Guidelines).
Drug Interactions
In an in situ rat intestinal permeability model, valganciclovir hydrochloride tablets showed no interaction with valacyclovir, didanosine, nelfinavir, cyclosporine, omeprazole, or mycophenolate mofetil. Since valganciclovir is metabolized to ganciclovir, drug interactions involving ganciclovir also apply.
Imipenem‑cilastatin
Seizures have been reported with concomitant use. Co‑administration is not recommended unless the benefit outweighs the risk.
Probenecid
Concomitant use reduces renal clearance of ganciclovir by 20% and increases exposure by 40%, requiring close monitoring for toxicity.
Zidovudine
Concomitant use increases the AUC of zidovudine by 17%. Both agents may cause neutropenia and anemia, and some patients may not tolerate the combination.
Didanosine
Concomitant use may increase plasma concentrations of didanosine.
Mycophenolate mofetil
Competition for renal tubular secretion may increase concentrations of MPAG and ganciclovir. Monitoring is recommended in patients with renal impairment.
Trimethoprim
Reduces renal clearance of ganciclovir by 16.3% and prolongs half‑life by 15%, with no significant effect on AUC or Cmax; clinical relevance is limited.
Cyclosporine
Concomitant use may increase serum creatinine levels, without significant changes in cyclosporine pharmacokinetics.
Other agents
Concomitant use with myelosuppressive or nephrotoxic drugs (e.g., dapsone, amphotericin B, nucleoside analogs) may increase toxicity and requires careful risk‑benefit assessment.
