Mebendazole

DESCRIPTION

VERMOX® (mebendazole) is a (synthetic) broad-spectrum anthelmintic available as chewable tablets, each containing 100 mg of mebendazole. Inactive ingredients are: colloidal silicon dioxide, corn starch, hydrogenated vegetable oil, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, sodium saccharin, sodium starch glycolate, talc, tetrarome orange, and FD&C yellow No. 6.

Mebendazole is methyl 5-benzoylbenzimidazole-2-carbamate. Mebendazole is a white to slightly yellow powder with a molecular weight of 295.29. It is less than 0.05% soluble in water, dilute mineral acid solutions, alcohol, ether and chloroform, but is soluble in formic acid.

CLINICAL PHARMACOLOGY

Following administration of 100 mg twice daily for three consecutive days, plasma levels of VERMOX® (mebendazole) and its primary metabolite, the 2-amine, do not exceed 0.03 µg/mL and 0.09 µg/mL, respectively. All metabolites are devoid of anthelmintic activity. In man, approximately 2% of administered VERMOX® is excreted in urine and the remainder in the feces as unchanged drug or a primary metabolite.

Mode of Action

VERMOX® inhibits the formation of the worms' microtubules and causes the worms' glucose depletion.

INDICATIONS

VERMOX® (mebendazole) is indicated for the treatment of Enterobius vermicularis (pinworm), Trichuris trichiura (whipworm), Ascaris lumbricoides (common roundworm), Ancylostoma duodenale (common hookworm), Necator americanus (American hookworm) in single or mixed infections.

Efficacy varies as a function of such factors as pre-existing diarrhea and gastrointestinal transit time, degree of infection, and helminth strains. Efficacy rates derived from various studies are shown in the table below:

DOSAGE AND ADMINISTRATION

The same dosage schedule applies to children and adults. The tablet may be chewed, swallowed, or crushed and mixed with food.

If the patient is not cured three weeks after treatment, a second course of treatment is advised. No special procedures, such as fasting or purging, are required.

HOW SUPPLIED

VERMOX® (mebendazole) is available as chewable tablets, each containing 100 mg of mebendazole, and is supplied in boxes of twelve tablets.

NDC 50458-110-01 (blister package of 12)

Store at controlled room temperature (59°-77° F/ 15°-25° C).

SIDE EFFECTS

Transient symptoms of abdominal pain and diarrhea have occurred in cases of massive infection and expulsion of worms. Hypersensitivity reactions such as rash, urticaria and angioedema have been observed on rare occasions. Very rare cases of convulsions have been reported.

DRUG INTERACTIONS

Preliminary evidence suggests that cimetidine inhibits mebendazole metabolism and may result in an increase in plasma concentrations of mebendazole.

WARNINGS

There is no evidence that VERMOX® (mebendazole), even at high doses, is effective for hydatid disease. There have been rare reports of neutropenia and liver function elevations, including hepatitis, when VERMOX® is taken for prolonged periods and at dosages substantially above those recommended.

PRECAUTIONS

Carcinogenesis and Mutagenesis

In carcinogenicity tests of mebendazole in mice and rats, no carcinogenic effects were seen at doses as high as 40 mg/kg given daily over two years. Dominant lethal mutation tests in mice showed no mutagenicity at single doses as high as 640 mg/kg. Neither the spermatocyte test, the F₁ translocation test, nor the Ames test indicated mutagenic properties.

Impairment of Fertility

Doses up to 40 mg/kg in mice, given to males for 60 days and to females for 14 days prior to gestation, had no effect upon fetuses and offspring, though there was slight maternal toxicity.

Use in Pregnancy

Pregnancy Category C. Mebendazole has shown embryotoxic and teratogenic activity in pregnant rats at single oral doses as low as 10 mg/kg. In view of these findings the use of VERMOX® is not recommended in pregnant women. In humans, a post-marketing survey has been done of a limited number of women who inadvertently had consumed VERMOX® during the first trimester of pregnancy. The incidence of spontaneous abortion and malformation did not exceed that in the general population. In 170 deliveries on term, no teratogenic risk of VERMOX® was identified. During pregnancy, especially during the first trimester, VERMOX® should be used only if the potential benefit justifies the potential risk to the fetus.

Nursing Mothers

It is not known whether VERMOX® is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when VERMOX® is administered to a nursing woman.

Pediatric Use

The drug has not been extensively studied in children under two years; therefore, in the treatment of children under two years the relative benefit/ risk should be considered.