Ganciclovir !

An intravenous antiviral for cytomegalovirus (CMV) in transplant recipients and people with AIDS. Its main danger is low blood counts.

Updated 2026-11-01

Class: Anti-herpesvirus agents
Enzyme: CMV DNA polymerase (activated by the viral UL97 kinase)
ATC code: J05AB06

CMV DNA polymerase (activated by the viral UL97 kinase)Ganciclovir

The figure shows ganciclovir in herpes simplex virus 1 thymidine kinase; in CMV the first phosphate is added instead by the viral kinase UL97, and the triphosphate then blocks the viral DNA polymerase.

Target in 3D: CMV DNA polymerase (activated by the viral UL97 kinase). PDB structure 1KI2 (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Ganciclovir is a guanosine analogue. In CMV-infected cells the viral kinase UL97 adds the first phosphate (in herpes simplex, the viral thymidine kinase), and cellular enzymes make ganciclovir triphosphate. The triphosphate competes with dGTP, is preferentially used by the viral DNA polymerase and slows and stops the viral DNA chain. Resistance comes from mutations in UL97 or in the polymerase.

Viral UL97 kinase phosphorylates ganciclovir in CMV-infected cells
Cellular kinases make ganciclovir triphosphate
The triphosphate competes with dGTP at the viral DNA polymerase
Viral DNA elongation stops

Pharmacokinetics

Absorption: Given intravenously; its oral prodrug is valganciclovir
Elimination: By the kidneys, unchanged; haemodialysis removes about half
Half-life: About 3.5 hours with normal kidney function

Indications

CMV retinitis in immunocompromised adults, including people with AIDS Cytomegalovirus infection →
Prevention of CMV disease in transplant recipients at risk Cytomegalovirus infection →

Adverse effects

Common

Fever
Diarrhoea and nausea
Leukopenia and anaemia
Headache and cough

Contraindications

Hypersensitivity to ganciclovir or valganciclovir

Key interactions

Zidovudine and other myelosuppressive drugs (e.g. mycophenolate): Additive bone marrow suppression
Imipenem-cilastatin: Seizures have been reported
Ciclosporin, amphotericin B and other nephrotoxic drugs: Higher risk of kidney injury
Probenecid: Raises ganciclovir levels

What is monitored

Complete blood count with differential and platelets, frequently
Serum creatinine (doses depend on kidney function)
Regular eye examinations in CMV retinitis
Pregnancy test before starting

Administration and safety

Intravenous infusion only, over about an hour: never as a rapid injection, intramuscular or subcutaneous
The reconstituted solution is alkaline: avoid contact with skin and eyes, and handle as a hazardous drug
Adequate hydration during treatment
Look-alike/sound-alike risk with valganciclovir and aciclovir

Nursing care

Check the blood count before each course and as ordered; hold and report if neutrophils or platelets are low
Watch for fever, sore throat, bleeding or bruising
Use protective handling as for cytotoxic drugs
Teach effective contraception: women during treatment and for at least 30 days after; men, condoms for at least 90 days after

Pregnancy and breastfeeding

Toxic to the fetus in animal studies; a pregnancy test is done before treatment and contraception is used during and after it.

Test yourself

Think of the answer, then tap the question to see it.

Which CMV enzyme activates ganciclovir?

The viral kinase UL97, which adds the first phosphate.

What is the main toxicity of ganciclovir?

Bone marrow suppression, especially neutropenia.

Why is ganciclovir combined with zidovudine only with great care?

Both suppress the bone marrow, so severe neutropenia and anaemia are more likely.

Which antibiotic combination with ganciclovir has been linked to seizures?

Imipenem-cilastatin.

Add to my cards (4)

Cytomegalovirus infection

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - GANCICLOVIR injection, powder, lyophilized, for solution (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 62 (McGraw Hill, 2023).

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Representative model, for educational purposes only.