Ganciclovir (Ophthalmic implant)
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 BRAND NAMES
 MECHANISM OF ACTION
Ganciclovir is a synthetic nucleoside analogue of 2'-deoxyguanosine, e that, upon phosphorylation, inhibits DNA replication by herpes simplex viruses (HSV). Ganciclovir is transformed by viral and cellular thymidine kinases (TK) to ganciclovir triphosphate, which works as an antiviral agent by inhibiting the synthesis of viral DNA in 2 ways:
- Competitive inhibition of viral DNA-polymerase
- It enters in competition with deoxyguanosine triphosphate and it's direct incorporation into viral primer strand DNA, prevents DNA chain elongation.
Ganciclovir (Ophthalmic implant) is indicated for the treatment of cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS).
Ganciclovir intravitreal implantation is designed to release the drug over a 5 to 8 month period of time. Following depletion of ganciclovir from the implant, as evidenced by progression of retinitis, the implant may be removed and replaced.
- Patients with hypersensitivity to ganciclovir or acyclovir, and in patients with any contraindications for intraocular surgery, such as external infection or severe thrombocytopenia.
 WARNINGS AND PRECAUTIONS
- Potential complications accompanying intraocular surgery to place the Ganciclovir (Ophthalmic implant) into the vitreous cavity may include, but are notlimited to, the following: vitreous loss, vitreous hemorrhage, cataract formation, retinal detachment, uveitis, endophthalmitis, and decrease in visual acuity.
- Following implantation of the Vitrasert Implant, nearly all patients will experience an immediate and temporary decrease in visual acuity in the implanted eye which lasts for approximately
two to four weeks post-operatively. This decrease in visual acuity is likely a result of the surgical implant procedure.
- ganciclovir has caused decreased sperm production in animals and may cause infertility in humans
- ganciclovir has caused tumors in animals. Although there is no information from human studies, ganciclovir should be considered a potential carcinogen.
No drug interactions have been observed
 PREGNANCY AND LACTATION
- Pregnancy Category C (US). Women of childbearing potential should be advised that ganciclovir causes birth defects in animals and should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
- Nursing Mothers: It is not known whether Ganciclovir from the Ophthalmic implant is excreted in human milk. Because many drugs are excreted in human milk and, because carcinogenicity and teratogenicity effects occurred in animals treated with ganciclovir, mothers should be instructed to discontinue nursing if they have a Ganciclovir Ophthalmic implant
 SIDE EFFECTS
During the first two months following implantation, visual acuity loss of 3 lines or more, vitreous hemorrhage, and retinal detachments occurred in approximately 10-20% of patients. Cataract formation/lens opacities, macular abnormalities, intraocular pressure spikes, optic disk/nerve changes, hyphemas and uveitis occurred in approximately 1-5%. Adverse events with an incidence of less than 1% were: retinopathy, anterior chamber cell and flare, synechia, hemorrhage (other than vitreous), cotton wool spots, keratopathy, astigmatism, endophthalmitis, microangiopathy, sclerosis, choroiditis, chemosis, phthisis bulbi, angle closure glaucoma with anterior chamber shallowing, vitreous detachment, vitreous traction, hypotony, severe post-operative inflammation, retinal tear, retinal hole, corneal dellen, choroidal folds, pellet extrusion from scleral wound, and gliosis