What Other Drugs Interact with Avir?
If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.
Avir has no known severe interactions with other drugs.
Avir has no known serious interactions with other drugs.
Moderate interactions of Avir include:
Minor interactions of Avir include:
This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.
Avir may harm an unborn baby. Use effective birth control while taking Avir and for at least 3 days after your last dose.
Avir is pregnancy category C. Data on the use of Avir in pregnant women are limited, though the available evidence suggests no difference in congenital abnormalities in the children of women who were accidentally treated with Avir during mass prevention campaigns compared with those who were not. In mass prevention campaigns for which the World Health Organization (WHO) has determined that the benefit of treatment outweighs the risk, WHO allows use of Avir in the 2nd and 3rd trimesters of pregnancy. However, the risk of treatment in pregnant women who are known to have an infection needs to be balanced with the risk of disease progression in the absence of treatment.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
It is not known whether Avir is excreted in human milk. Avir should be used with caution in breastfeeding women.
The safety of Avir in children less than 6 years old is not certain. Studies of the use of Avir in children as young as one year old suggest that its use is safe. According to WHO guidelines for mass prevention campaigns, Avir can be used in children as young as 1 year old. Many children less than 6 years old have been treated in these campaigns with Avir, albeit at a reduced dose.
Dosage Forms And Strengths
- Tablet: 200 mg
Each white to off-white, circular, biconvex, bevel-edged film coated, TILTAB tablet is debossed with “ap” and “550” and contains 200 mg of Avir.
Bottles of 2 Tablets NDC 52054-550-22 Bottles of 28 Tablets NDC 52054-550-28
What Are Side Effects Associated with Using Avir?
Common side effects of Avir include:
This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.
Avir is a synthetic nitroimidazole with a broad spectrum of antinematodal activity similar to that of mebendazole but with anticestodal and some antiprotozoal action. Mebendazole is no longer manufactured in the United States, and its use has been supplanted by Avir. The advantage of Avir over mebendazole is its activity in a single oral dose of 400 mg (200 mg for children 68,69
Because intestinal helminthiasis typically is multiparasitic, Avir is an almost ideal agent. 70,71 It has good activity in multiple doses against cutaneous larva migrans and strongyloidiasis, but single-dose therapy with ivermectin is more effective for these two helminthic infections. 72,73 Successful treatment with Avir of visceral larva migrans has been reported, although ivermectin is the drug of choice. 74 Efficacy against the microfilarial stage of Wuchereria bancrofti, Brugia malayi, and Loa loa is well documented, although diethylcarbamazine (DEC) remains the parasite adulticidal drug of choice for the treatment of patients with these filarial infections. 75–77 DEC plus Avir in combination has superior activity against adult W. bancrofti compared with either drug alone. 78 Avir may be of benefit in patients with gnathostomiasis, baylisascariasis, trichinellosis, toxociariasis, capillariasis, and angiostrongyliasis.
Prolonged high-dose regimens of Avir constitute the most effective medical treatment of larval cestode disease caused by Echinococcus granulosus, E. multilocularis, and E. vogelii. 79 Dosage is not defined for children younger than 6 years of age. Treatment is tailored to response and normally is required for a minimum of several weeks or months. Avir should be started several days before surgery to minimize the effect of intraoperative spillage of cyst contents. Avir also is used in the treatment of patients with cysticercosis, often with concomitant steroids. 80–82
Avir binds irreversibly to the nematodal isoform of β-tubulin, blocking microtubule assembly, disrupting tegumental integrity, inhibiting motility, and impeding glucose uptake by the worm. Detectable levels are achieved in serum, cerebrospinal fluid, cyst fluid, and bile, with a serum half-life of 8 to 15 hours depending on the dose. Rapid, extensive hepatic biotransformation to the active metabolite, Avir sulfoxide, occurs, but the major route of excretion is not clear.
Side effects of low-dose Avir therapy are minimal, consisting of diarrhea, abdominal pain, migration of Ascaris through the mouth or nose, and rare hypersensitivity. With high-dose or prolonged therapy, elevated levels of hepatic transaminases, dizziness, neutropenia, and alopecia are most common. 83 Serum hepatic enzyme levels and the blood count should be monitored every 2 weeks during high-dose therapy.
Lack of data for children younger than 2 years of age has precluded specific US labeling for or establishment of dosage for this age group, although the label leaves the physician discretion in electing to treat children younger than 2 years of age. The pediatric dosage is identical to the adult dosage. Embryotoxic potential usually precludes the use of Avir during pregnancy.
Avir is manufactured as a suspension and as tablets that can be crushed with food, chewed, or taken whole. Avir is poorly absorbed and should be ingested with food, preferably a fatty meal, to maximize absorption.