In clinical studies have shown good tolerability of the drug Famvir, including patients with reduced immunity. Reported cases of headaches and nausea, but these events were mild or moderately expressed and observed with the same frequency as that of patients receiving placebo. The remaining adverse events were identified through post-marketing surveillance.
Adverse events reported in clinical trials in patients test steroid with reduced immunity, coincided with those observed in patients with normal immune systems.
Mental Disorders: rare – confusion (predominantly in elderly patients); rarely – hallucinations.Disorders of the nervous system: very often – headache; often – dizziness; rarely – somnolence (predominantly in elderly patients). Violations of the heart: rarely – palpitations. Violations of the gastrointestinal tract: often – nausea, vomiting, abdominal pain, diarrhea. Violations of the liver and biliary tract: rarely cholestatic . jaundice Disorders of the skin and subcutaneous tissue disorders: often – a rash, itching;rarely – angioedema (swelling of the face, eyelids, periorbital region, throat), urticaria; the frequency is not known – severe skin reactions * (including exudative erythema multiforme, Stevens-Johnson syndrome, Lyell’s syndrome (toxic epidermal necrolysis), leukocytoclastic vasculitis (allergic). Laboratory and instrumental data: often – a violation of liver function. * – AE, not noted in clinical trials identified in post-marketing surveillance, as well described in the literature.
There are limited data on overdose famciclovir. Treatment: symptomatic and supportive. Failure to comply with the recommendations to reduce the dose of famciclovir in view of kidney function in patients with kidney disease is rarely observed cases of acute renal failure. Penciclovir, which is the active metabolite of famciclovir, appear in hemodialysis. Penciclovir concentrations in plasma are reduced by 75% after dialysis for 4 hours.
The interaction with other drugs and other interactions
The combined use with probenecid may test steroid increase penciclovir plasma concentrations. To prevent the development of toxic reactions and possible dose reduction is necessary to monitor the patients receiving the drug Famvir 500 mg concurrently with probenecid.
There were no clinically significant changes in pharmacokinetic parameters of penciclovir following a single application (500 mg) from the field receiving antacids ( magnesium or aluminum hydroxide) or in patients treated before treatment (multiple dose) allopurinol, cimetidine, theophylline, zidovudine, promethazine. In single dose of famciclovir (500 mg), together with emtricitabine or zidovudine showed no changes in pharmacokinetic parameters of penciclovir, zidovudine, a metabolite of zidovudine and emtricitabine.
For a single or repeated application of famciclovir (500 mg 3 times daily) digoxin with no change and the pharmacokinetic parameters of penciclovir digoxin. Given that the conversion of the inactive metabolite, 6-dezoksipentsiklovira (formed by deacetylation of famciclovir) to penciclovir is catalyzed by the enzyme aldegidoksidazoy may develop drug interactions when using with drugs metabolized with the participation of the enzyme and inhibits its activity. When applying famciclovir with cimetidine and promethazine, which are inhibitors of aldehyde oxidase in vitro, showed no reduction of the formation of penciclovir famciclovir. However, when receiving famciclovir with potent inhibitor of aldehyde oxidase in vitro, raloxifene, may reduce the formation of penciclovir famciclovir, and as a result, the efficiency of famciclovir. It is necessary to evaluate the clinical efficacy of the antiviral therapy, while the use of raloxifene.
Given that famciclovir is a weak inhibitor of aldehyde oxidase in vitro, possibly its impact on the pharmacokinetic parameters of drugs metabolized with the participation of the enzyme.
In experimental studies famciclovir had no inducing effect on cytochrome system, and I did not inhibit isoenzyme .
Treatment should begin immediately after diagnosis.
Genital herpes – a disease transmitted through sexual contact. During recurrence risk of infection increases. In the presence of clinical manifestations of the disease, even in the event of an antiviral treatment, patients should avoid sexual intercourse.
During suppressive treatment with antiviral agents frequency spread of viral infection is significantly reduced, however, the risk of transmission is theoretically exist. Therefore, patients should take appropriate protective measures during sexual intercourse.
The drug composition of the tablets of 125 mg, 250 mg and 500 mg of lactose enters. Famvir should not be used in patients with rare hereditary disorders associated with galactose intolerance, severe lactase deficiency or glucose-galactose malabsorption.
Famciclovir has no pronounced effect on semen analysis, sperm morphology and motility of human. Reduced fertility was observed in an experimental model in male rats treated with famciclovir 500 mg / kg body weight; . expressed in female fertility decline were observed in rats . tolerated dose and duration of treatment Famvir Famvir was well tolerated in the treatment of test steroid when used at a dose of 750 mg 3 times a day for 7 days; in patients with genital herpes when used at a dose of 750 mg three times a day for 5 days in a dose of 500 mg three times a day for 10 days. It was also shown that the drug was well tolerated at suppressive therapy at a dose of 250 mg three times a day for 12 months for the treatment of genital herpes. Famvir well tolerated in patients with reduced immunity in treating Varicella zoster when receiving 500 mg three times a day for 10 days as well as Herpes Simplex, when receiving up to 500 mg two times a day for 7 days or 500 mg twice a day for 8 weeks.