Valcyte Special Precautions

General: Cross hypersensitivity: Due to the similarity of the chemical structure of ganciclovir and that of aciclovir and penciclovir, a cross-hypersensitivity reaction between these drugs is possible. Caution should therefore be used when prescribing Valcyte to patients with known hypersensitivity to aciclovir or penciclovir (or to their prodrugs, valaciclovir or famciclovir respectively).
Mutagenicity, teratogenicity, carcinogenicity, fertility and contraception: In animal studies ganciclovir was found to be mutagenic, teratogenic, carcinogenic and to impair fertility. Valcyte should therefore be considered a potential teratogen and carcinogen in humans with the potential to cause birth defects and cancers. Prior to initiation of valganciclovir treatment, patients should be advised of the potential risks to the fetus and to use contraceptive measures. Based on clinical and nonclinical studies, Valcyte may cause temporary or permanent inhibition of spermatogenesis (see Females and Males of Reproductive Potential, Pregnancy, Lactation under Use in Pregnancy & Lactation, Adverse Reactions, Pharmacology: Toxicology: Nonclinical Safety under Actions and Special Instructions for Use, Handling and Disposal under Cautions for Usage).
Myelosuppression: Valcyte should be used with caution in patients with pre-existing hematological cytopenia or a history of drug-related hematological cytopenia and in patients receiving radiotherapy.
Severe leukopenia, neutropenia, anemia, thrombocytopenia, pancytopenia, bone marrow failure and aplastic anemia have been observed in patients treated with Valcyte (and ganciclovir). Therapy should not be initiated if the absolute neutrophil count is less than 500 cells/μL or the platelet count is less than 25000/μL or the hemoglobin is less than 8 g/dL (see Special Dosage Instructions under Dosage & Administration, Precautions and Adverse Reactions).
It is recommended that complete blood counts and platelet counts be monitored in all patients during therapy, particularly in patients with renal impairment and in neonates and infants (see Use in Children as follows).
In patients with severe leukopenia, neutropenia, anemia and/or thrombocytopenia treatment with hematopoietic growth factors and/or the interruption of therapy is recommended (see Adverse Reactions).
Seizures have been reported in patients taking imipenem-cilastatin and ganciclovir. Valcyte should not be used concomitantly with imipenem-cilastatin unless the potential benefits outweigh the potential risks (see Interactions).
Zidovudine and Valcyte each have the potential to cause neutropenia and anemia. Some patients may not tolerate concomitant therapy at full dosage (see Interactions).
Didanosine plasma concentrations may increase during concomitant use with Valcyte; therefore, patients should be closely monitored for didanosine toxicity (see Interactions).
Concomitant use of other drugs that are known to be myelosuppressive or associated with renal impairment with Valcyte may result in added toxicity (see Interactions).
Drug Abuse and Dependence: No information is available for drug abuse and dependence with Valcyte.
Ability to Drive and Use Machines: Adverse reactions such as seizures, dizziness, and confusion have been reported with the use of Valcyte and/or ganciclovir (see Adverse Reactions). If they occur, such effects may affect tasks requiring alertness including the patient's ability to drive and operate machinery.
Renal Impairment: In patients with impaired renal function, dosage adjustments based on creatinine clearance are required (see Special Dosage Instructions under Dosage & Administration and Pharmacology: Pharmacokinetics: Pharmacokinetics in Special Populations under Actions).
Hepatic Impairment: Safety and efficacy have not been established in this patient population (see Special Dosage Instructions under Dosage & Administration and Pharmacology: Pharmacokinetics: Pharmacokinetics in Special Populations under Actions).
Use in Children: A higher risk of hematological cytopenias in neonates and infants warrants careful monitoring of blood counts in these age groups. Monitoring of liver function abnormalities, renal function and gastrointestinal fluid loss is also recommended in pediatric patients.
See Indications, Standard Dosage: Pediatric patients under Dosage & Administration, Clinical Trials under Adverse Reactions, and Pharmacology: Pharmacodynamics: Clinical/Efficacy Studies: Pediatric patients and Pharmacokinetics: Pharmacokinetics in Special Populations: Pediatric population under Actions.
Use in the Elderly: Safety and efficacy have not been established in this patient population (see Special Dosage Instructions under Dosage & Administrations and Pharmacology: Pharmacokinetics: Pharmacokinetics in Special Populations under Actions).