Antiviral Prodrug: Valganciclovir Powder for Oral Solution contains valganciclovir hydrochloride, an L-valyl ester prodrug of ganciclovir.1
Formulation: It is supplied as a powder to be reconstituted with water to form an oral solution, providing a concentration of 50 mg of valganciclovir per mL.2
Ease of Administration: The oral solution formulation is specifically designed for pediatric patients and adults who have difficulty swallowing tablets, allowing for flexible and accurate dosing based on body weight.
Targeted Activity: Valganciclovir is specifically active against viruses of the herpes family, most notably cytomegalovirus (CMV), which is the primary focus of its therapeutic use.3
Advantages
Accurate Pediatric Dosing: The liquid formulation allows for precise dose calculation based on a child’s body surface area or body weight, which is crucial for pediatric patients and is not possible with fixed-dose tablets.4
High Bioavailability: After reconstitution and oral administration, valganciclovir is rapidly converted to ganciclovir, providing a reliable and high systemic drug level that is superior to oral ganciclovir.5
Convenient for Patients: The oral solution offers a convenient and non-invasive alternative to intravenous ganciclovir, improving patient quality of life and compliance.
Effective CMV Prevention: It is highly effective in preventing CMV disease in high-risk solid organ transplant recipients, significantly reducing the incidence of infection and associated complications.
Uses
Prevention of CMV Disease: The primary licensed indication is for the prevention of cytomegalovirus (CMV) disease in high-risk adult and pediatric solid organ transplant recipients.
Pediatric Patients: It is specifically indicated for the prevention of CMV disease in pediatric patients (from birth to 18 years of age) who have received a solid organ transplant from a CMV-positive donor.
CMV Retinitis: It can also be used for the treatment of CMV retinitis in adult patients with AIDS, though tablets are more common for this indication.
Off-Label Uses: While not specifically licensed for all of these, it is also used in other situations where CMV infection poses a threat, such as in other immunocompromised states.
Nature
Antiviral Prodrug: Valganciclovir is a prodrug, meaning it is an inactive compound that is rapidly converted to the active drug, ganciclovir, inside the body.6
Mechanism of Action: After being converted to ganciclovir, the drug enters CMV-infected cells.7 Inside these cells, a viral enzyme (UL97 protein kinase) phosphorylates ganciclovir to its active triphosphate form.8 This active form then competitively inhibits viral DNA polymerase and is incorporated into the viral DNA, which terminates chain elongation and blocks viral replication.9
Selective Inhibition: The drug’s mechanism relies on a viral enzyme, making it highly selective for infected cells and less toxic to uninfected host cells.
Renal Excretion: Ganciclovir, the active drug, is primarily eliminated by renal excretion.10 Therefore, dose adjustments are required for patients with impaired kidney function to prevent toxicity.
Storage
Unreconstituted Powder: The powder for oral solution should be stored at controlled room temperature, typically between 20∘C to 25∘C (68∘F to 77∘F).
Reconstituted Solution: The reconstituted solution must be stored refrigerated at a temperature of 112∘C to 128∘C (1336∘F to 1446∘F) and is stable for a limited time (e.g., 49 days, though check the specific product’s instructions).15
Protection: Both the powder and the reconstituted solution must be protected from light and moisture.
Administration: The oral solution should always be taken with food to maximize absorption.16 The bottle should be shaken well before each use, and a calibrated measuring device should be used for accurate dosing.
