Pronunciation /ɡænˈsaɪkləvɪər/ MedlinePlus a605011 CAS ID 82410-32-0 | AHFS/Drugs.com Monograph Routes ofadministration IV, oral, intravitreal Molar mass 255.23 g/mol | |
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Trade names Cytovene; Cymevene; Vitrasert Pregnancycategory AU: DUS: C (Risk not ruled out) | ||
Ganciclovir is an antiviral medication used to treat cytomegalovirus (CMV) infections. A prodrug form with improved oral bioavailability (valganciclovir) has also been developed.
Contents
- Ganciclovir
- Medical use
- Adverse effects
- Toxicity
- Mechanism of action
- Pharmacokinetics
- Administration
- References
Ganciclovir was approved for medical use in 1994.
Ganciclovir
Medical use
Ganciclovir is indicated for:
It is also used for acute CMV colitis in HIV/AIDS and CMV pneumonitis in immunosuppressed patients.
Ganciclovir has also been used with some success in treating Human herpesvirus 6 infections.
Ganciclovir has also been found to be an effective treatment for herpes simplex virus epithelial keratitis.
Adverse effects
Ganciclovir is commonly associated with a range of serious haematological adverse effects. Common adverse drug reactions (≥1% of patients) include: granulocytopenia, neutropenia, anaemia, thrombocytopenia, fever, nausea, vomiting, dyspepsia, diarrhea, abdominal pain, flatulence, anorexia, raised liver enzymes, headache, confusion, hallucination, seizures, pain and phlebitis at injection site (due to high pH), sweating, rash, itch, increased serum creatinine and blood urea concentrations.
Toxicity
Ganciclovir is considered a potential human carcinogen, teratogen, and mutagen. It is also considered likely to cause inhibition of spermatogenesis. Thus, it is used judiciously and handled as a cytotoxic drug in the clinical setting.
Mechanism of action
Ganciclovir is a synthetic analogue of 2′-deoxy-guanosine. It is first phosphorylated to ganciclovir monophosphate by a viral kinase encoded by the cytomegalovirus (CMV) gene UL97 during infection. Subsequently, cellular kinases catalyze the formation of ganciclovir diphosphate and ganciclovir triphosphate, which is present in 10-fold greater concentrations in CMV or herpes simplex virus (HSV)-infected cells than uninfected cells.
Ganciclovir triphosphate is a competitive inhibitor of deoxyguanosine triphosphate (dGTP) incorporation into DNA and preferentially inhibits viral DNA polymerases more than cellular DNA polymerases. In addition, ganciclovir triphosphate serves as a poor substrate for chain elongation, thereby disrupting viral DNA synthesis by a second route.
Pharmacokinetics
Absorption of the oral form is very limited—about 5% fasting, about 8% with food. It achieves a concentration in the central nervous system of about 50% of the plasma level. About 90% of plasma ganciclovir is eliminated unchanged in the urine, with a half-life of 2–6 hours, depending on renal function (elimination takes over 24 hours in end-stage renal disease).
Administration
Acute infections are treated in two phases:
Stable disease is treated with 1000 mg orally three times daily. Similar dosing is used to prevent disease in high-risk patients, such as those infected with human immunodeficiency virus (HIV) or those with organ transplants.
Ganciclovir is also available in slow-release formulations for insertion into the vitreous humour of the eye, as treatment for CMV retinitis (associated with HIV infection).
A topical ophthalmic gel preparation of ganciclovir was recently approved for the treatment of acute herpes simplex keratitis.