Valganciclovir Dose Administration Protocol
Standard Adult Dosing
For CMV retinitis and most CMV disease in adults, administer valganciclovir 900 mg orally twice daily for 21 days as induction therapy, followed by 900 mg once daily for maintenance therapy. 1, 2
Induction Phase
- 900 mg orally twice daily for 21 days is the standard induction regimen for CMV retinitis and most CMV disease 1
- Valganciclovir is rapidly absorbed from the gastrointestinal tract and metabolized to ganciclovir in the intestine and liver 1
- This oral regimen produces systemic ganciclovir exposure comparable to intravenous ganciclovir 5 mg/kg twice daily 3
Maintenance Phase
- 900 mg once daily after completing induction therapy 1
- Maintenance therapy should continue for life unless immune reconstitution occurs (CD4+ count >100 cells/µL sustained for 3-6 months in HIV patients) 1
CMV Colitis Specific Protocol
For CMV colitis, initiate intravenous ganciclovir 5 mg/kg twice daily for 3-5 days, then transition to oral valganciclovir 900 mg twice daily for the remainder of a 2-3 week course. 2
- This sequential approach allows for initial IV therapy when gastrointestinal absorption may be compromised, followed by oral therapy 4
- Consultation with an infectious disease specialist is recommended early in treatment 2
Renal Dose Adjustments
Dose reduction is mandatory in patients with impaired renal function based on creatinine clearance (CrCl). 5
Adult Renal Dosing Table:
| CrCl (mL/min) | Induction Dose | Maintenance Dose |
|---|---|---|
| ≥60 | 900 mg twice daily | 900 mg once daily |
| 40-59 | 450 mg twice daily | 450 mg once daily |
| 25-39 | 450 mg once daily | 450 mg every 2 days |
| 10-24 | 450 mg every 2 days | 450 mg twice weekly |
| <10 (hemodialysis) | Not recommended | Not recommended |
- Monitor serum creatinine regularly and adjust doses accordingly throughout treatment 5
- For males, calculate CrCl using: (140-age) × body weight (kg) / [72 × serum creatinine (mg/dL)] 5
- For females, multiply the male value by 0.85 5
Pediatric Dosing
For children old enough to receive adult dosing, valganciclovir is preferred over oral ganciclovir, but limited data exists for appropriate pediatric dosing. 1, 2
Pediatric Calculation Formula:
- Dose (mg) = 7 × BSA × CrCl (where BSA is body surface area in m² and CrCl is creatinine clearance) 5
- Maximum dose should not exceed 900 mg 5
- Round all calculated doses to the nearest 10 mg increment 5
- For treatment of active CMV infection, administer the calculated dose twice daily 6
Pediatric CrCl Estimation:
- CrCl (mL/min/1.73m²) = k × Height (cm) / Serum Creatinine (mg/dL) 5
- k values vary by age: 0.33 for low birth weight infants <1 year, 0.45 for appropriate birth weight infants <1 year and children 1-2 years, 0.55 for boys 2-13 years and girls 2-16 years, 0.7 for boys 13-16 years 5
Critical Monitoring Requirements
Hematologic Monitoring
Complete blood counts with differential and platelet counts must be performed frequently due to the high risk of myelosuppression. 7, 5
- Myelosuppression is the major dose-limiting toxicity, requiring dose reduction or interruption in up to 40% of patients 2, 7
- Monitor CBC twice weekly during induction therapy and once weekly during maintenance 7
- Avoid valganciclovir if absolute neutrophil count <500 cells/µL, platelet count <25,000/µL, or hemoglobin <8 g/dL 5
- Severe neutropenia may require granulocyte colony-stimulating factor 7
Renal Function Monitoring
- Monitor serum creatinine regularly and adjust doses as renal function changes 2, 7, 5
- Renal toxicity can occur and may require dose modification 7
Ophthalmologic Monitoring (for CMV Retinitis)
- Regular ophthalmologic examinations are required throughout treatment 2
Special Populations and Considerations
Transplant Recipients
- Valganciclovir is highly acceptable for pre-emptive therapy in allogeneic hematopoietic stem cell transplant recipients without substantial gastrointestinal GVHD 2
- Do not use valganciclovir in patients with hepatic dysfunction, particularly liver transplant patients, due to higher rates of CMV disease compared with IV ganciclovir 2
- For prophylaxis in renal transplant recipients, 450 mg daily may be as effective as 900 mg daily with potentially less toxicity 8
Alternative Therapy for Intolerance
- For patients who cannot tolerate valganciclovir or ganciclovir due to neutropenia or thrombocytopenia, foscarnet is the standard alternative 2
- Combination therapy with ganciclovir and foscarnet may be considered for sight-threatening disease or treatment failure 2
Common Pitfalls and Safety Considerations
Handling Precautions
Do not break or crush tablets; valganciclovir is considered a potential teratogen and carcinogen. 5
- Avoid direct contact with broken or crushed tablets 5
- If skin or mucous membrane contact occurs, wash thoroughly with soap and water, and rinse eyes with plain water 5
- Handle and dispose according to guidelines for antineoplastic drugs 5
Drug Interactions and Contraindications
- Contraindicated in patients with clinically significant hypersensitivity to valganciclovir or ganciclovir 5
- Use with caution in patients with pre-existing cytopenias or those receiving myelosuppressive drugs or irradiation 5
- Cytopenia may occur at any time during treatment and may worsen with continued dosing 5
Food Effects
- Administer with food to maximize absorption; food increases ganciclovir AUC by 24-56% 3