Recommended Oral Dosage of Valganciclovir for CMV Infection
The recommended oral dosage of valganciclovir for treatment of cytomegalovirus (CMV) infection is 900 mg twice daily for 21 days for induction therapy, followed by 900 mg once daily for maintenance therapy.
Adult Dosing Recommendations
- For induction treatment of CMV infection, valganciclovir should be administered at 900 mg (two 450 mg tablets) orally twice daily for 21 days 1
- For maintenance treatment following induction, or for patients with inactive CMV retinitis, the recommended dosage is 900 mg (two 450 mg tablets) orally once daily 1
- For CMV colitis, initial treatment with intravenous ganciclovir 5 mg/kg twice daily for 3-5 days is recommended, followed by oral valganciclovir 900 mg twice daily for the remainder of the 2-3 week course 2, 3
- Valganciclovir is a prodrug of ganciclovir that is rapidly metabolized to the active form in the intestine and liver, providing excellent oral bioavailability 3
Dosing in Special Populations
Renal Impairment
- Dosage adjustment is required based on creatinine clearance (CrCl) 1:
- CrCl ≥60 mL/min: Standard dose (900 mg twice daily for induction; 900 mg once daily for maintenance)
- CrCl 40-59 mL/min: 450 mg twice daily for induction; 450 mg once daily for maintenance
- CrCl 25-39 mL/min: 450 mg once daily for induction; 450 mg every 2 days for maintenance
- CrCl 10-24 mL/min: 450 mg every 2 days for induction; 450 mg twice weekly for maintenance
- CrCl <10 mL/min: Not recommended 1
Transplant Recipients
- For prevention of CMV disease in adult kidney transplant recipients, 900 mg once daily is recommended starting within 10 days of transplantation until 200 days post-transplantation 1
- For heart or kidney-pancreas transplant recipients, 900 mg once daily is recommended starting within 10 days of transplantation until 100 days post-transplantation 1
- Valganciclovir is a highly acceptable oral option for pre-emptive therapy for CMV in allogeneic hematopoietic stem cell transplant (HCT) recipients in the absence of substantial gastrointestinal graft-versus-host disease (GVHD) 2
Monitoring During Treatment
- Regular monitoring of complete blood count is essential due to the risk of myelosuppression 3
- Renal function should be monitored regularly as renal toxicity can occur 3
- Dose reduction or interruption might be necessary in up to 40% of patients due to hematologic toxicity 3
Important Considerations and Cautions
- Valganciclovir should not be used in patients with hepatic dysfunction, particularly liver transplant patients, due to higher rates of CMV disease compared with intravenous ganciclovir 2
- It is postulated that hepatic dysfunction allows bioabsorption of valganciclovir but decreases cleavage of the valine ester, thereby limiting conversion to the active form 2
- For patients who cannot tolerate valganciclovir or ganciclovir due to neutropenia or thrombocytopenia, foscarnet is commonly used as an alternative 2
- For CMV infections that are refractory or resistant to valganciclovir, ganciclovir, foscarnet, or cidofovir, maribavir has shown promise in clinical trials 2
Efficacy Considerations
- Pharmacokinetic studies have demonstrated that oral valganciclovir at 900 mg daily provides systemic ganciclovir exposure similar to intravenous ganciclovir at 5 mg/kg 4, 5
- For prophylaxis in kidney transplant recipients, some studies suggest that a lower dose of 450 mg daily may provide comparable efficacy with reduced toxicity compared to the 900 mg dose 6, 7
- However, for active CMV infection treatment, the full dose of 900 mg twice daily is recommended to ensure adequate viral suppression 3, 1