valganciclovir hydrochloride: clinical use

Prescribing considerations

• Confirm the licensed indication and CMV donor/recipient status where relevant.
• Individualise treatment according to renal function; paediatric transplant prescribing also uses body surface area.
• Review concurrent myelosuppressive and nephrotoxic therapy before and during treatment.
• Consider reproductive toxicity, contraception and possible temporary or permanent impairment of spermatogenesis.
• Experience in lung and intestinal transplant recipients is limited; safety and efficacy in hepatic impairment and adults over 65 have not been established.

Contraindications and cautions

• Hypersensitivity to valganciclovir, ganciclovir or a formulation excipient.
• Breastfeeding.
• Do not initiate when blood-cell indices are below the product-defined thresholds.
• Film-coated tablets should not be used in patients undergoing haemodialysis; consult oral-solution product information and specialist protocols.
• Use caution where there is hypersensitivity to aciclovir, penciclovir or their prodrugs because cross-reactions are possible.

Monitoring

• Full blood count, including differential white-cell and platelet counts, before and regularly during treatment.
• Renal function before and regularly during treatment, with prompt review after clinically important changes.
• Height, weight and renal function during paediatric transplant prophylaxis.
• Clinical and virological response where CMV progression or antiviral resistance is suspected.

Clinical pharmacology

Valganciclovir is the L-valyl ester prodrug of ganciclovir. Conversion occurs through intestinal and hepatic esterases. Activated ganciclovir triphosphate preferentially accumulates in infected cells and inhibits viral DNA polymerase and DNA-chain elongation. Ganciclovir is mainly eliminated unchanged through glomerular filtration and active tubular secretion.

Formulation and product differences

• Tablets must be swallowed whole and must not be crushed or divided.
• The oral solution permits accurately measured, individualised administration and may be used when tablets cannot be swallowed.
• Systemic ganciclovir exposure is equivalent between the oral solution and tablet formulations.
• The reconstituted solution requires refrigeration and has a limited in-use shelf life.
• The oral solution contains sodium benzoate, which may worsen jaundice in newborn babies up to four weeks old.

Oral solution

Route: Oral

Strengths: 50 mg/mL

Tablet

Route: Oral

Strengths: 450 mg