Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Gel, Ophthalmic:
Zirgan: 0.15% (5 g) [contains benzalkonium chloride]
Pharmacology
Mechanism of Action
Ganciclovir is phosphorylated to a substrate, which competitively inhibits the binding of deoxyguanosine triphosphate to DNA polymerase resulting in inhibition of DNA replication by herpes simplex viruses.
Pharmacokinetics/Pharmacodynamics
Absorption
Negligible systemic absorption (0.1% in comparison to IV doses and 0.04% in comparison to oral valganciclovir)
Use: Labeled Indications
Herpetic keratitis: Treatment of acute herpetic keratitis (dendritic ulcers)
Contraindications
There are no contraindications listed in the manufacturer’s labeling.
Dosage and Administration
Dosing: Adult
Herpetic keratitis: Ophthalmic: Apply 1 drop in affected eye 5 times daily (approximately every 3 hours while awake) until corneal ulcer heals, then apply 1 drop 3 times daily for 7 days
Dosing: Geriatric
Refer to adult dosing.
Dosing: Pediatric
Herpetic keratitis: Children ≥2 years and Adolescents: Ophthalmic gel: Apply 1 drop in affected eye 5 times daily (approximately every 3 hours while awake) until corneal ulcer heals, then 1 drop 3 times daily for 7 days
Administration
For ophthalmic application only; avoid touching tip of applicator to eye or other surfaces.
Storage
Store at 15°C to 25°C (59°F to 77°F). Do not freeze.
Drug Interactions
There are no known significant interactions.
Adverse Reactions
>10%: Ophthalmic: Blurred vision (60%), eye irritation (20%)
1% to 10%: Ophthalmic: Punctate keratitis (5%), conjunctival hyperemia (5%)
Warnings/Precautions
Concerns related to adverse effects:
- Ocular adverse events: Blurred vision commonly occurs; may also cause eye irritation.
Special populations:
- Contact lens wearers: Contact lenses should not be worn during the course of therapy or in any patient with signs/symptoms of herpetic keratitis.
Other warnings/precautions:
- Appropriate use: For topical ophthalmic use only.
Monitoring Parameters
Ophthalmologic exams
Pregnancy
Pregnancy Risk Factor
C
Pregnancy Considerations
Adverse events were observed in animal reproduction studies conducted with systemic ganciclovir. The amount of ganciclovir available systemically following topical application of the ophthalmic gel is significantly less in comparison to IV doses (0.1%).
Patient Education
- Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
- Patient may experience blurred vision. Have patient report immediately to prescriber vision changes, eye pain, or severe eye irritation (HCAHPS).
- Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.
