Cymevene 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 Cymevene 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. Cymevene should therefore be considered a potential teratogen and carcinogen in humans with the potential to cause birth defects and cancers. Prior to initiation of ganciclovir treatment, patients should be advised of the potential risks to the fetus and to use contraceptive measures. Based on clinical and nonclinical studies, Cymevene may cause temporary or permanent inhibition of spermatogenesis in males (see Use in Pregnancy & Lactation, Adverse Reactions, Pharmacology: Toxicology: Preclinical Safety under Actions, and Special Instructions for Use, Handling and Disposal under Cautions for Usage).
Myelosuppression: Cymevene 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 Cymevene. Therapy should not be initiated if the absolute neutrophil count is less than 500 cells/μL or the platelet count is less than 25,000 cells/μL or the hemoglobin is less than 8 g/dL (see 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 (see Special dosage instructions under Dosage & Administration).
In patients with severe leukopenia, neutropenia, anemia and/or thrombocytopenia, that treatment with hematopoietic growth factors and/or the interruption of therapy is recommended (see Adverse Reactions).
Use with other medicines: Seizures have been reported in patients taking imipenem-cilastatin and ganciclovir. Cymevene should not be used concomitantly with imipenem-cilastatin unless the potential benefits outweigh the potential risks (see Interactions).
Zidovudine and Cymevene 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 Cymevene; 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 Cymevene may result in added toxicity (see Interactions).
Drug Abuse and Dependence: No information is available for drug abuse and dependence with Cymevene.
Ability to Drive and Use Machines: No studies on the effect on the ability to drive and use machines have been performed. Based on the adverse reaction profile, ganciclovir may have a minor influence on the ability to drive and use machines. Adverse reactions, for example seizures, dizziness and confusion may occur in patients receiving Cymevene (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 renal impairment, dosage adjustments based on creatinine clearance are required (see Special dosage instructions: Patients with renal impairment under Dosage & Administration and Pharmacology: Pharmacokinetics: Pharmacokinetics in Special Populations under Actions).
Hepatic Impairment: The safety and efficacy of Cymevene have not been studied in patients with hepatic impairment (see Special dosage instructions under Dosage & Administration and Pharmacology: Pharmacokinetics: Pharmacokinetics in Special Populations under Actions).
Use in Children: See Special dosage instructions under Dosage & Administration and Pharmacology: Pharmacokinetics: Pharmacokinetics in Special Populations under Actions.
Use in the Elderly: See Special dosage instructions under Dosage & Administration and Pharmacology: Pharmacokinetics: Pharmacokinetics in Special Populations under Actions.