Zovirax Injection – FDA prescribing information, side effects and uses

Zovirax Injection - FDA prescribing information, side effects and uses

Long-term use of acyclovir for up to 10 years for HSV suppression is effective and well tolerated. Eliminate herpes without making manage of drugs or over the counters. Avoid touching an infected area and then touching your eyes. acyclovir shingles acyclovir cream complete drug acyclovir cheap 34th ed. Some people may also use the medication to treat and prevent future outbreaks of genital herpes. AskDocWeb: The pain of shingles and can be severe and prescription medications are frequently needed. Acyclovir sodium is a white, crystalline powder with the molecular formula C8H10N5NaO3 and a molecular weight of 247.19.

A major difference between acyclovir and valacyclovir pertains to their bioavailability, or how efficiently they are absorbed into the bloodstream after ingestion. At physiologic pH, acyclovir sodium exists as the un-ionized form with a molecular weight of 225 and a maximum solubility in water at 37°C of 2.5 mg/mL. FDA pregnancy category B. Aciclo-GTP is a sexually transmitted acyclovir valtrex and patients should avoid intercourse when they have visible acyclovir valtrex Resistance to acyclovir can prices for acyclovir zovirax acyclovir with overuse. Symptoms usually associated with such a reaction include difficulty breathing or swallowing, chest tightness, swelling, skin rashes, and hives. Trying to determine the correct dosage without the help of your doctor is a bad idea. In vitro, acyclovir triphosphate stops replication of herpes viral DNA.

Each capsule of ZOVIRAX contains 200 mg of acyclovir and the inactive ingredients corn starch, lactose, magnesium stearate, and sodium lauryl sulfate. The greater antiviral activity of acyclovir against HSV compared to VZV is due to its more efficient phosphorylation by the viral TK. Follow the directions on your prescription label. Sensitivity testing results, expressed as the concentration of drug required to inhibit by 50% the growth of virus in cell culture (IC50), vary greatly depending upon a number of factors. Using plaque-reduction assays, the IC50 against herpes simplex virus isolates ranges from 0.02 to 13.5 mcg/mL for HSV-1 and from 0.01 to 9.9 mcg/mL for HSV-2. It also increases the chances of spreading the virus to other areas of your body. Acyclovir also demonstrates activity against the Oka vaccine strain of VZV with a mean IC50 of 1.35 mcg/mL.

Valacyclovir works best if it is used within 48 hours after the first symptoms of shingles or genital herpes (e. While most of the acyclovir-resistant mutants isolated thus far from such patients have been found to be TK-deficient mutants, other mutants involving the viral TK gene (TK partial and TK altered) and DNA polymerase have been isolated. Take the missed dose as soon as you remember. The possibility of viral resistance to acyclovir should be considered in patients who show poor clinical response during therapy. The pharmacokinetics of acyclovir after intravenous administration have been evaluated in adult patients with normal renal function during Phase 1/2 studies after single doses ranging from 0.5 to 15 mg/kg and after multiple doses ranging from 2.5 to 15 mg/kg every 8 hours. The database we use does not list numbness as a possible side effect of Acyclovir. Average steady-state peak and trough concentrations from 1-hour infusions administered every 8 hours are given in Table 1.

My valacyclovir generic to acyclovir conversion boyfriend a velvetlined deluxe very tiny number either 50 rogaine generic form. Plasma protein binding is relatively low (9% to 33%) and drug interactions involving binding site displacement are not anticipated. This is not a complete list of side effects and others may occur. The only major urinary metabolite detected is 9-carboxymethoxymethylguanine accounting for up to 14.1% of the dose in patients with normal renal function. ZOVIRAX was administered at a dose of 2.5 mg/kg to 6 adult patients with severe renal failure. AskDocWeb: Erectile dysfunction is not listed among the possible side effects of Acyclovir. Acyclovir pharmacokinetics were determined in 16 pediatric patients with normal renal function ranging in age from 3 months to 16 years at doses of approximately 10 mg/kg and 20 mg/kg every 8 hours (Table 3).

For recurrent outbreaks of genital herpes, valacyclovir works best if it is used within 24 hours after the symptoms begin to appear. Acyclovir pharmacokinetics were determined in 12 patients ranging in age from birth to 3 months at doses of 5 mg/kg, 10 mg/kg, and 15 mg/kg every 8 hours (Table 3). This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Dosage reduction may be required in geriatric patients with underlying renal impairment (see PRECAUTIONS: Geriatric Use). A multicenter trial of ZOVIRAX for Injection at a dose of 250 mg/m2 every 8 hours (750 mg/m2/day) for 7 days was conducted in 98 immunocompromised patients (73 adults and 25 children) with orofacial, esophageal, genital, and other localized infections (52 treated with ZOVIRAX and 46 with placebo). ZOVIRAX decreased virus excretion, reduced pain, and promoted healing of lesions. In placebo-controlled trials, 58 patients with initial genital herpes were treated with intravenous ZOVIRAX 5 mg/kg or placebo (27 patients treated with ZOVIRAX and 31 treated with placebo) every 8 hours for 5 days.

Zovirax do not apply various other items (make-up, lip balms) to the same area where the medication is being applied. Sixty-two patients ages 6 months to 79 years with brain biopsy-proven herpes simplex encephalitis were randomized to receive either ZOVIRAX (10 mg/kg every 8 hours) or vidarabine (15 mg/kg/day) for 10 days (28 were treated with ZOVIRAX and 34 with vidarabine). Multum’s drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The proportion of patients treated with ZOVIRAX functioning normally or with only mild sequelae (e.g., decreased attention span) was 32% compared to 12% of patients treated with vidarabine. Patients less than 30 years of age and those who had the least severe neurologic involvement at time of entry into study had the best outcome with treatment with ZOVIRAX. An additional controlled study performed in Europe demonstrated similar findings. Two hundred and two infants with neonatal herpes simplex infections were randomized to receive either ZOVIRAX 10 mg/kg every 8 hours (n = 107) or vidarabine 30 mg/kg/day (n = 95) for 10 days.

One study examined rates of genital herpes transmission in heterosexual couples when only one partner was initially infected 1. A multicenter trial of ZOVIRAX for Injection at a dose of 500 mg/m2 every 8 hours for 7 days was conducted in immunocompromised patients with zoster infections (shingles). Ninety-four (94) patients were evaluated (52 patients were treated with ZOVIRAX and 42 with placebo). ZOVIRAX was superior to placebo as measured by reductions in cutaneous dissemination and visceral dissemination. ZOVIRAX for Injection is intended for intravenous infusion only, and should not be administered topically, intramuscularly, orally, subcutaneously, or in the eye. Intravenous infusions must be given over a period of at least 1 hour to reduce the risk of renal tubular damage (see PRECAUTIONS and DOSAGE AND ADMINISTRATION). Renal failure, in some cases resulting in death, has been observed with acyclovir therapy (see ADVERSE REACTIONS: Observed During Clinical Practice and OVERDOSAGE).
Zovirax Injection - FDA prescribing information, side effects and uses

It slows the growth and spread of the herpes virus so that the body can fight off the infection. Precipitation of acyclovir crystals in renal tubules can occur if the maximum solubility of free acyclovir (2.5 mg/mL at 37°C in water) is exceeded or if the drug is administered by bolus injection. Ensuing renal tubular damage can produce acute renal failure. Abnormal renal function (decreased creatinine clearance) can occur as a result of acyclovir administration and depends on the state of the patient’s hydration, other treatments, and the rate of drug administration. Concomitant use of other nephrotoxic drugs, pre-existing renal disease, and dehydration make further renal impairment with acyclovir more likely. Approximately 1% of patients receiving intravenous acyclovir have manifested encephalopathic changes characterized by either lethargy, obtundation, tremors, confusion, hallucinations, agitation, seizures, or coma. ZOVIRAX should be used with caution in those patients who have underlying neurologic abnormalities and those with serious renal, hepatic, or electrolyte abnormalities, or significant hypoxia.

Cold Sores (Nongenital Herpes Simplex Infections) Herpes simplex infections are common and when they appear around the mouth and lips, people often refer to them as cold sores and fever blisters. Plasma drug concentrations in animal studies are expressed as multiples of human exposure to acyclovir at the higher and lower dosing schedules (see CLINICAL PHARMACOLOGY: Pharmacokinetics). Acyclovir was tested in lifetime bioassays in rats and mice at single daily doses of up to 450 mg/kg administered by gavage. There was no statistically significant difference in the incidence of tumors between treated and control animals, nor did acyclovir shorten the latency of tumors. At 450 mg/kg/day, plasma concentrations in both the mouse and rat bioassay were lower than concentrations in humans. Acyclovir did not impair fertility or reproduction in mice (450 mg/kg/day, p.o.) or in rats (25 mg/kg/day, s.c.). In the mouse study, plasma levels were the same as human levels, while in the rat study, they were 1 to 2 times human levels.

Other oral medications include famciclovir, which is a prodrug that is converted to penciclovir, and valacyclovir, which is a prodrug that is converted to acyclovir. In a rat peri- and post-natal study at 50 mg/kg/day, s.c., there was a statistically significant decrease in group mean numbers of corpora lutea, total implantation sites, and live fetuses. No testicular abnormalities were seen in dogs given 50 mg/kg/day, IV for 1 month (1 to 3 times human levels) or in dogs given 60 mg/kg/day orally for 1 year (the same as human levels). Testicular atrophy and aspermatogenesis were observed in rats and dogs at higher dose levels. Pregnancy Category B. Acyclovir administered during organogenesis was not teratogenic in the mouse (450 mg/kg/day, p.o.), rabbit (50 mg/kg/day, s.c. and IV), or rat (50 mg/kg/day, s.c.).

Acyclovir capsules, USP and acyclovir tablets, USP are formulations for oral administration. There are no adequate and well-controlled studies in pregnant women. A prospective epidemiologic registry of acyclovir use during pregnancy was established in 1984 and completed in April 1999. There were 749 pregnancies followed in women exposed to systemic acyclovir during the first trimester of pregnancy resulting in 756 outcomes.The occurrence rate of birth defects approximates that found in the general population. However, the small size of the registry is insufficient to evaluate the risk for less common defects or to permit reliable or definitive conclusions regarding the safety of acyclovir in pregnant women and their developing fetuses. Acyclovir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Acyclovir concentrations have been documented in breast milk in 2 women following oral administration of ZOVIRAX and ranged from 0.6 to 4.1 times corresponding plasma levels.

Famciclovir and valacyclovir offer improved oral bioavailability and convenient oral dosing schedules but are more expensive than acyclovir. ZOVIRAX should be administered to a nursing mother with caution and only when indicated. Clinical studies of ZOVIRAX for Injection did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients. Other reported clinical experience has identified differences in the severity of CNS adverse events between elderly and younger patients (see ADVERSE REACTIONS: Observed During Clinical Practice). In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased renal function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

The oral acyclovir dosage for treatment of primary or initial nonprimary genital herpes is 200 mg five times daily for 10 days. The most frequent adverse reactions reported during administration of ZOVIRAX were inflammation or phlebitis at the injection site in approximately 9% of the patients, and transient elevations of serum creatinine or BUN in 5% to 10% (the higher incidence occurred usually following rapid [less than 10 minutes] intravenous infusion). Nausea and/or vomiting occurred in approximately 7% of the patients (the majority occurring in nonhospitalized patients who received 10 mg/kg). Itching, rash, or hives occurred in approximately 2% of patients. Elevation of transaminases occurred in 1% to 2% of patients. In addition to adverse events reported from clinical trials, the following events have been identified during post-approval use of ZOVIRAX for Injection in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made.

Zovirax is one of the most highly effective and safest medical drugs for the treatment of the herpes infection. Overdoses involving ingestions of up to 20 g have been reported. Adverse events that have been reported in association with overdosage include agitation, coma, seizures, and lethargy. Precipitation of acyclovir in renal tubules may occur when the solubility (2.5 mg/mL) is exceeded in the intratubular fluid. Overdosage has been reported following bolus injections or inappropriately high doses, and in patients whose fluid and electrolyte balance were not properly monitored. This has resulted in elevated BUN and serum creatinine, and subsequent renal failure. In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored (see DOSAGE AND ADMINISTRATION).

Herpes labialis, or cold sores, are caused by herpes simplex virus type 1 (HSV-1) and can result in significant irritation, pain, discomfort, and worry (18, 25). In neonatal herpes simplex infections, doses of 15 mg/kg or 20 mg/kg (infused at a constant rate over 1 hour every 8 hours) have been used; the safety and efficacy of these doses are not known. For patients who require dialysis, the mean plasma half-life of acyclovir during hemodialysis is approximately 5 hours. This results in a 60% decrease in plasma concentrations following a 6-hour dialysis period. Therefore, the patient’s dosing schedule should be adjusted so that an additional dose is administered after each dialysis. The resulting solution contains 50 mg acyclovir per mL (pH approximately 11). Shake the vial well to assure complete dissolution before measuring and transferring each individual dose.

Two-Day Regimen of Acyclovir for Treatment of Recurrent Genital Herpes Simplex Virus Type 2 Infection. Refrigeration of reconstituted solution may result in the formation of a precipitate which will redissolve at room temperature. The calculated dose should then be removed and added to any appropriate intravenous solution at a volume selected for administration during each 1-hour infusion. Infusion concentrations of approximately 7 mg/mL or lower are recommended. In clinical studies, the average 70-kg adult received between 60 and 150 mL of fluid per dose. Higher concentrations (e.g., 10 mg/mL) may produce phlebitis or inflammation at the injection site upon inadvertent extravasation. Standard, commercially available electrolyte and glucose solutions are suitable for intravenous administration; biologic or colloidal fluids (e.g., blood products, protein solutions, etc.) are not recommended.

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