Favirox, 500 mg 7 pcs

How to take, the dosage

The drug should be taken orally, regardless of meals, without chewing, with water. Treatment with the drug should be started as soon as possible, immediately after the appearance of the first symptoms of the disease (tingling, itching and burning).

Infections caused by VZV (herpes zoster), including ophthalmoherpes in immunocompetent patients:

The recommended dose is 500 mg 3 times daily for 7 days.

Infection caused by VZV (herpes zoster) in immunocompromised patients:

The recommended dose is 500 mg 3 times daily for 10 days.

Infection caused by HSV (labial or genital herpes) in immunocompromised patients:

– For a first episode of genital herpes, the recommended dose is 250 mg 3 times daily for 5 days;

– For relapses of genital herpes, 1000 mg 2 times daily for 1 day or 125 mg 2 times daily for 5 days or 500 mg once, followed by 3 doses of 250 mg every 12 hours.

– For relapses of labial herpes – 1500 mg once daily for 1 day or 750 mg twice daily for 1 day.

Infection caused by HSV (orolabial or genital herpes) in immunocompromised patients:

The recommended dose is 500 mg twice daily for 7 days.

To prevent exacerbations of genital herpes (suppressive therapy), 250 mg 2 times daily is used. The duration of therapy depends on the severity of the disease. Periodic evaluation of possible changes in the course of the disease after 12 months is recommended.

In HIV-infected patients, the effective dose is 500 mg 2 times a day.

Patients aged ≥65 years

In elderly patients with normal renal function, dosing adjustment of famcyclovir is not necessary.

Patients with impaired renal function

Patients with impaired renal function have decreased clearance of penciclovir.

Recommendations for dosing regimen adjustment in immunocompetent patients with impaired renal function based on creatinine clearance are presented in Table 1.

Recommendations for dosing regimen adjustment in immunocompromised patients with impaired renal function as a function of creatinine clearance are presented in Table 2.

Table 1. Dosing regimen correction in immunocompromised patients with impaired renal function

< 20

Table 2. Dosing regimen correction in immunocompromised patients with impaired renal function

Patients with renal impairment who are on hemodialysis or receiving a hemodialysis procedure

Because penciclovir plasma concentrations are reduced by 75% after a 4-hour hemodialysis procedure, famiclovir should be taken immediately after the hemodialysis procedure. See Tables 1 and 2 for a recommended dose adjustment regimen.

Patients with hepatic impairment

There is no need for dose adjustment in patients with mild to moderate hepatic impairment.

There is no experience of using the drug in patients with severe hepatic impairment.

Patients of the Negro race

The efficacy of a 1-day dosage of famcyclovir 1000 mg twice daily for the treatment of genital herpes relapse in immunocompetent patients of the Negro race was not greater than that of placebo. The clinical significance of drug dosing regimens for the treatment of both genital herpes relapses (within 2 or 5 days) and other infectious lesions caused by VZV and HSV is unknown.

Interaction

Concomitant use with probenecid may increase the concentration of penciclovir in the blood plasma. To prevent the development of toxic reactions, patients receiving Favirox at a dose of 500 mg concomitantly with probenecid should be monitored, taking into account the possibility of reducing the dose of famiclovir.

No clinically significant changes of pharmacokinetic parameters of pencyclovir were noted in single administration (500 mg dose) immediately after administration of antacids (magnesium and aluminum hydroxide) or in patients who received prior treatment with allopurinol, cimetidine, theophylline, zidovudine, promethazine (multiple administration).

No changes in pharmacokinetic parameters of penciclovir, zidovudine, the metabolite of zidovudine (zidovudine glucuronide) and emtricitabine were found during single administration of famiclovir (500 mg dose) together with emtricitabine or zidovudine.

No changes in pharmacokinetic parameters of penciclovir and digoxin were observed during the single and repeated use of famcyclovir (in the dose of 500 mg three times a day) together with digoxin.

Given that the conversion of the inactive metabolite 6-deoxypencyclovir (formed during deacetylation of famcyclovir) into pencyclovir is catalyzed by the enzyme aldehydoxidase, drug interaction may occur when using Favirox together with the drugs metabolized with participation of this enzyme or inhibiting its activity.

When using famcyclovir together with cimetidine and prometazine that are aldehydoxidase inhibitors in vitro, no disturbance of penciclovir formation from famcyclovir was found. However, when taking famcyclovir together with a potent in vitro aldehydoxidase inhibitor, raloxifene, there may be disruption of penciclovir formation from famcyclovir, and as a consequence, the effectiveness of famcyclovir is reduced. It is necessary to evaluate the clinical efficacy of antiviral therapy in concomitant use with raloxifene.

Given that famcyclovir is a weak inhibitor of aldehydroxidase in vitro, its effect on pharmacokinetic parameters of drugs metabolized with the participation of this enzyme is possible.
In experimental studies famcyclovir had no inducing effect on cytochrome P450 system and did not inhibit CYP3A4 enzyme.

Special Instructions

Treatment should begin as soon as the diagnosis is made.
Genital herpes is a sexually transmitted disease. During relapses, the risk of infection increases. In the presence of clinical manifestations of the disease even if antiviral treatment is begun, patients should avoid sexual intercourse.

During suppressive therapy with antiviral agents the frequency of virus transmission decreases markedly, but the risk of transmission nevertheless remains. In connection with the above, during treatment with the drug during this period, safe sexual behavior should be observed.

Effect on the ability to drive vehicles and vehicles.
No effect of Favirox on the ability to drive motor transport and/or operate machinery is expected, but patients with dizziness, somnolence, mental confusion or other disorders of the central nervous system during Favirox administration should refrain from driving motor transport and/or operating machinery during the drug use.

Contraindications

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Side effects

In clinical trials good tolerability of famcyclovir was shown, including in patients with reduced immunity.

Cases of headache and nausea were reported, but these phenomena were mild to moderately expressed and were noted with the same frequency in patients receiving placebo. The remaining adverse events (AEs) were detected in clinical practice during drug administration in the post-registration period.

AEs reported during clinical trials in immunocompromised patients were the same as those reported in patients with normal immunity.

The World Health Organization (WHO) criteria were used to assess the incidence of adverse reactions: Very common (> 1/10); common (from> 1/100, < 1/10); infrequent (> 1/1000, <1/100); rare (> 1/10000, < 1/1000); very rare (< 1/10000), frequency unknown.

Blood and lymphatic system disorders: rare – thrombocytopenia;

Mental disorders: infrequent – confusion of consciousness (mainly in elderly patients); rare – hallucinations;

Nervous system disorders: very common – headache, frequent – dizziness, infrequent – somnolence (mainly in elderly patients), frequency unknown – seizures*;

Heart disorders: rare – feeling of “palpitations”;

Gastrointestinal tract disorders: frequent – nausea, vomiting, abdominal pain, diarrhea;

Violations of the liver and biliary tract: rare – cholestatic jaundice;

Violations of the immune system: frequency unknown – anaphylactic shock*, anaphylactic reaction*;

Skin and subcutaneous tissue disorders: frequently – rash, itching; infrequently – angioedema (swelling of the face, eyelids, periorbital area, throat), urticaria; frequency unknown – severe skin reactions* (incl.erythema multiforme, Stevens-Johnson syndrome, Lyell syndrome (toxic epidermal necrolysis), allergic vasculitis.)

Laboratory and instrumental data: often – liver function abnormalities

* – NTs that were not observed during clinical trials, revealed in post-marketing observations, as well as those described in the literature. Since the information on these NIs was obtained by spontaneous reports and the exact number of patients who took the drug is not determined, it is not possible to estimate the frequency of these reactions, in this regard for these NIs it is indicated “frequency unknown”
If any of the side effects mentioned in the instructions worsen, or if you notice any other side effects not specified in the instructions, please inform your doctor about it.

Overdose

There are limited data on famcyclovir overdose.

Cases of famcyclovir overdose (10.5 g) with no clinical manifestations have been described.

Treatment: symptomatic and supportive. In patients with renal disease, cases of acute renal failure have rarely been reported when the recommendations to reduce the dose of famcyclovir were not followed, taking into account renal function. Penciclovir, which is the active metabolite of famcyclovir, is excreted by hemodialysis. Plasma concentrations of penciclovir decrease by 75% after hemodialysis for 4 hours.

Pregnancy use

No embryotoxic and teratogenic effects of famcyclovir and penciclovir were observed in animal studies. In studies of oral administration of famcyclovir, pencyclovir was excreted with the milk of lactating rats. It is unknown whether pencyclovir is excreted with breast milk in humans.

However, since the data on the safety of use of famcyclovir in pregnant and breastfeeding women is insufficient, its use during pregnancy and breastfeeding is possible only if the benefits of therapy for the mother exceed the potential risk to the fetus and child.

There are no data requiring special recommendations for patients with preserved reproductive potential.
Famcyclovir has no pronounced effect on the spermogram, morphology or motility of human spermatozoa. A decrease in fertility was observed in an experimental model in male rats treated with famcyclovir at a dose of 500 mg/kg body weight, no pronounced decrease in fertility was observed in female rats.