What is the administration protocol for ganciclovir (antiviral medication) in treating cytomegalovirus (CMV) infections?

Ganciclovir Administration Protocol

Intravenous ganciclovir should be administered at 5 mg/kg every 12 hours over 1-2 hours for induction therapy lasting 14-21 days, followed by lifelong maintenance therapy at 5 mg/kg once daily for disseminated CMV disease in HIV-infected patients. 1

Induction Therapy Protocols

Standard Adult Dosing

• Administer 5 mg/kg intravenously every 12 hours for 14-21 days as induction therapy for CMV retinitis and disseminated disease in HIV-infected adults 1
• Each dose must be infused slowly over 1-2 hours to minimize toxicity 1
• For CMV encephalitis specifically, use 5 mg/kg IV every 12 hours for 2-3 weeks, though monotherapy often fails 1

Pediatric Dosing

• For HIV-infected children with disseminated CMV disease: 5 mg/kg/dose twice daily IV over 1-2 hours for 14-21 days 1
• For symptomatic congenital CMV in newborns: 4-6 mg/kg IV every 12 hours for 6 weeks (the higher 12 mg/kg/day total dose shows superior viral suppression) 1
• All CMV disease in pediatric transplant recipients requires IV ganciclovir treatment 2

Gastrointestinal CMV Infection

• 5 mg/kg IV every 12 hours for 14 days for gastrointestinal CMV infections, with 75% showing positive clinical response 3
• For CMV colitis specifically, consider initial IV ganciclovir 5 mg/kg twice daily for 3-5 days, then transition to oral valganciclovir 900 mg twice daily for remainder of 2-3 week course 4

Maintenance Therapy

Long-term Suppression

• Following induction, administer 5 mg/kg IV once daily as lifelong maintenance therapy 1
• Maintenance therapy with 6 mg/kg daily has also been used successfully 3
• CMV disease is not cured with current antiviral agents; secondary prophylaxis is required for life 1

Alternative: Sequential IV-to-Oral Approach

• A short course combining 5 days of IV ganciclovir 5 mg/kg twice daily followed by 16 days of oral valganciclovir 900 mg twice daily achieved viral load eradication in 66.7% of solid organ transplant patients 5
• This approach may shorten hospital stays while maintaining therapeutic efficacy 5

Combination Therapy for Severe Disease

For CMV encephalitis or treatment failures, use combination therapy: ganciclovir 5 mg/kg IV every 12 hours PLUS foscarnet 60 mg/kg IV every 8 hours (or 90 mg/kg every 12 hours) for 3 weeks, followed by maintenance. 1, 2

• This combination achieved improvement or stabilization in 74% of HIV patients with CMV encephalitis or myelitis 1, 2
• Monotherapy with ganciclovir alone frequently fails for CNS disease 1

Critical Monitoring Requirements

Hematologic Surveillance

• Monitor complete blood count twice weekly during induction and once weekly during maintenance 6
• Myelosuppression (neutropenia, anemia, thrombocytopenia) is the major dose-limiting toxicity, requiring dose reduction or interruption in up to 40% of patients 1, 6
• Approximately two-thirds of neonates treated for congenital CMV develop substantial neutropenia 1
• Severe neutropenia may necessitate granulocyte colony-stimulating factor 1, 6

Renal Function Monitoring

• Monitor serum creatinine regularly as renal toxicity can occur and requires dose modification 1, 6
• Adjust doses for renal insufficiency 5

Virologic Monitoring

• Weekly CMV monitoring by nucleic acid testing or pp65 antigenemia during treatment 2
• For CMV retinitis, regular ophthalmologic examinations are essential 6

Common Pitfalls and Dose Adjustments

Infusion Rate

• Never infuse faster than the recommended 1-2 hour duration to avoid acute toxicity 1
• For foscarnet (when used in combination), infuse no faster than 1 mg/kg/minute over 2 hours 1

Neutropenia Management

• If severe neutropenia develops (absolute neutrophil count <500/mm³), consider dose reduction, treatment interruption, or addition of G-CSF 1, 6
• In neonates, neutropenia severe enough to require dose modification occurred in 48% and G-CSF in 7% 1

Resistance Development

• With long-term therapy, ganciclovir-resistant CMV strains can emerge 1
• Consider foscarnet or combination therapy for resistant infections 1

Additional Toxicities to Monitor

Beyond myelosuppression and nephrotoxicity, watch for:

• CNS effects 1
• Gastrointestinal dysfunction 1
• Thrombophlebitis at IV sites 1, 6
• Elevated liver enzymes 1, 6

Transplant-Specific Considerations

• KDIGO guidelines recommend all kidney transplant recipients (except donor/recipient both CMV-negative) receive oral ganciclovir or valganciclovir prophylaxis for at least 3 months post-transplant 2
• Valganciclovir should not be used in patients with hepatic dysfunction, particularly liver transplant patients, due to higher rates of CMV disease compared with IV ganciclovir 4