PRECAUTIONS
General
As with all intraocular surgery, sterility of the surgical field and the Vitrasert (ganciclovir)
Implant should be rigorously maintained. The Vitrasert (ganciclovir) Implant should be handled
only by the suture tab in order to avoid damaging the polymer coatings since
this could affect release rate of ganciclovir inside the eye. The Vitrasert (ganciclovir)
Implant should not be resterilized by any method.
A high level of surgical skill is required for implantation of the Vitrasert (ganciclovir)
Implant. A surgeon should have observed or assisted in surgical implantation
of the Vitrasert (ganciclovir) Implant prior to attempting the procedure.
Carcinogenesis, Mutagenesis
Ganciclovir was carcinogenic in the mouse at oral doses of 20 and 1000 mg/kg/day. At the dose of 1000 mg/kg/day there was a significant increase in the incidence of tumors of the preputial gland in males, forestomach (nonglandular mucosa) in males and females, and reproductive tissues (ovaries, uterus, mammary gland, clitoral gland, and vagina) and liver in females. At the dose of 20 mg/kg/day, a slightly increased incidence of tumors was noted in the preputial and harderian glands in males, forestomach in males and females, and liver in females. Except for histiocytic sarcoma of the liver, ganciclovir-induced tumors were generally of epithelial or vascular origin. Although the preputial and clitoral glands, forestomach, and harderian glands of mice do not have human counterparts, ganciclovir should be considered a potential carcinogen in humans.
Ganciclovir increased mutations in mouse lymphoma cells and DNA damage in human
lymphocytes in vitro at concentrations between 50-500 and 250-2000 µg/mL,
respectively. In the mouse micronucleus assay, ganciclovir was clastogenic at
doses of 150 and 500 mg/kg (IV) (2.8 - 10x human exposure based on AUC) but
not 50 mg/kg (exposure approximately comparable to the human based on AUC).
Ganciclovir was not mutagenic in the Ames Salmonella assay at concentrations
of 500-5000 µg/mL.
Impairment of Fertility
Ganciclovir caused decreased mating behavior, decreased fertility, and an increased incidence of embryolethality in female mice following intravenous doses of 90 mg/kg/day. Ganciclovir caused decreased fertility in male mice and hypospermatogenesis in mice and dogs following daily oral or intravenous administration of doses ranging from 0.2 - 10 mg/kg.
Pregnancy: Teratogenic Effects: Pregnancy Category C
Ganciclovir has been shown to be embryotoxic in rabbits and mice following
intravenous administration and teratogenic in rabbits. Fetal resorptions were
present in at least 85% of rabbits and mice administered 60 mg/kg/day and 108
mg/kg/day, respectively. Effects observed in rabbits included: fetal growth
retardation, embryolethality, teratogenicity, and/or maternal toxicity. Teratogenic
changes included cleft palate, anophthalmia/microphthalmia, aplastic organs
(kidney and pancreas), hydrocephaly, and brachygnathia. In mice, effects observed
were maternal/fetal toxicity and embryolethality.
Daily intravenous doses of 90 mg/kg administered to female mice prior to mating,
during gestation, and during lactation caused hypoplasia of the testes and seminal
vesicles in the month-old male offspring, as well as pathologic changes in the
nonglandular region of the stomach (see Carcinogenesis, Mutagenesis subsection).
Although each Vitrasert Implant contains from 4.5 to 6.4 mg of ganciclovir, which is released locally in the vitreous, there are no adequate and well-controlled studies in pregnant women on the effects of the Vitrasert (ganciclovir) Implant. Therefore, the Vitrasert (ganciclovir) Implant 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 Vitrasert (ganciclovir) Implant is excreted in human milk. Daily intravenous doses of 90 mg/kg administered to female mice prior to mating, during gestation, and during lactation caused hypoplasia of the testes and seminal vesicles in the month-old male offspring, as well as pathologic changes in the non-glandular region of the stomach. 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 Vitrasert (ganciclovir) Implant.
Pediatric Use
Safety and effectiveness in pediatric patients below 9 years of age have not been established.