Valganciclovir

Oral
Cytomegaloviral retinitis in AIDS patients

Oral
Prophylaxis of cytomegaloviral infections in immunocompromised patients

CrCl	Dosage
<10 and haemodialysis patients	Not recommended.
10-24	450 mg every 2 days (or 225 mg once daily) for induction; 450 mg twice wkly (or 125 mg once daily) for maintenance.
25-39	450 mg once daily for induction; 450 mg every 2 days (or 225 mg once daily) for maintenance.
40-59	450 mg bid for induction; 450 mg once daily for maintenance.
≥60	900 mg bid for induction; 900 mg once daily for maintenance.

Should be taken with food. Take during or immediately after meals.

Add 91 mL of purified water to provide a soln containing 250 mg per 5 mL. Tap the bottle to loosen the powder, then add water in 2 approx equal portions. Shake the bottle for 1 min after each addition.

Hypersensitivity. Haemodialysis patients (CrCl <10 mL/min). Lactation. Should not be administered if the absolute neutrophil count is <500 cells/μL, platelet count is <25,000/μL, or Hb is <8 g/dL.

Patient w/ pre-existing haematological cytopenia, history of drug-related haematological cytopenia. Renal impairment. Pregnancy.

Abdominal pain, diarrhoea, graft rejection, increased serum creatinine, headache, insomnia, nausea, paraesthesia, peripheral neuropathy, pyrexia, retinal detachment, tremors, vomiting.
Potentially Fatal: Severe leucopenia, neutropenia, anaemia, thrombocytopenia, pancytopenia, bone marrow depression, aplastic anaemia, acute renal failure.

May impair ability to drive or operate machinery. Avoid direct contact of broken or crushed tab w/ skin or mucous membranes.

Monitor CBC w/ differential, platelet count, serum creatinine.

Symptoms: Bone marrow depression (medullary aplasia), renal toxicity. Management: Maintain adequate hydration. May consider use of hematopoietic factors. Dialysis may be useful in reducing serum concentrations.

Convulsions may occur if taken concomitantly w/ imipenem-cilastatin. Increased exposure w/ probenecid. Increased risk of neutropenia and anaemia w/ zidovudine. May increase plasma concentrations of didanosine. Increased risk of neutropenia and leucopenia w/ mycophenolate mofetil. Increased risk of peripheral neuropathy w/ zalcitabine. Enhanced toxicity w/ other drugs that inhibit replication of rapidly dividing cells (e.g. dapsone, vincristine, vinblastine, amphotericin B, trimethoprim/sulfa combinations, nucleoside analogues, hydroxyurea), cidofovir, foscamet.

Food increases absorption.

Description: Valganciclovir is an L-valyl ester (prodrug) of ganciclovir that exists as a mixture of 2 diastereomers. After oral admin, both diastereomers are rapidly converted to ganciclovir by intestinal and hepatic esterases. Ganciclovir is a synthetic analogue of 2'-deoxyguanosine, which inhibits replication of human cytomegalovirus (CMV) in cell culture and in vivo.
Pharmacokinetics:
Absorption: Well absorbed from the GI tract. Increased absorption if taken w/ food. Bioavailability: Approx 60%. Time to peak plasma concentration: 1-3 hr.
Distribution: Widely distributed to all tissue including CSF and ocular tissue.
Metabolism: Converted to ganciclovir by rapid first-pass intestinal or hepatic metabolism.
Excretion: Via urine as ganciclovir.

Tab: Store at 25°C. Oral soln: Store at 25°C (dry powder); 2-8°C (after reconstitution).

Antivirals

Anon. Valganciclovir. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/08/2014.

Buckingham R (ed). Valganciclovir Hydrochloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 01/08/2014.

McEvoy GK, Snow EK, Miller J et al (eds). Valganciclovir Hydrochloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 04/08/2014.

Valcyte Film Coated Tablet, Powder for Solution (Genentech, Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/08/2014.