Vermox (Mebendazole): Side Effects, Uses, Dosage, Interactions, Warnings (2024)

Description for Vermox

VERMOX^™ (mebendazole) is an orally administered, synthetic 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.

Chemically, mebendazole is methyl 5-benzoylbenzimidazole-2-carbamate with a molecular formula of C₁₆H₁₃N₃O₃ and the following structural formula:

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.

Uses for Vermox

VERMOX™ CHEWABLE is indicated for the treatment of patients one year of age and older with gastrointestinal infections caused by Ascaris lumbricoides (roundworm) and Trichuris trichiura (whipworm).

Dosage for Vermox

The recommended dosage in patients one year of age and older is one VERMOX™ CHEWABLE 500 mg tablet taken as a single dose.

Chew VERMOX™ CHEWABLE 500 mg tablet completely before swallowing. Do not swallow the tablet whole.

For patients who have difficulty chewing the tablet, approximately 2 mL to 3 mL of drinking water can be added to a suitably sized spoon and the VERMOX™ CHEWABLE 500 mg tablet placed into the water. Within 2 minutes, the tablet absorbs the water and turns into a soft mass with semi-solid consistency, which can then be swallowed.

VERMOX™ CHEWABLE 500 mg tablet can be taken without regard to food intake [see CLINICAL PHARMACOLOGY].

HOW SUPPLIED

Dosage Forms And Strengths

Chewable Tablet

500 mg round, flat radius-edged white to yellowish chewable tablet that is debossed with “M/500” on one side and “J” on the other side.

Storage And Handling

VERMOX™ CHEWABLE tablets are supplied as 500 mg, round, flat radius-edged white to yellowish chewable tablets that are debossed with “M/500” on one side and “J” on the other side. They are supplied as follows:

Bottles of 200 tablets - NDC 50458-675-20

Store below 30°C. Keep container tightly closed. Unused tablets should be discarded 1 month after the bottle is first opened. When the bottle is first opened this Discard After date should be written on the bottle label in the place provided.

Manufactured by: Lusomedicamenta Lisbon, Portugal. Revised: Sep 2021

Side Effects for Vermox

Clinical Studies

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of mebendazole was evaluated in 6276 adult and pediatric subjects one year of age and older who participated in 39 clinical trials for treatment of single or mixed parasitic infections of the gastrointestinal tract. In these trials, the formulations, dosages and duration of mebendazole treatment varied. Adverse reactions reported in mebendazole-treated subjects from the 39 clinical trials are shown in Table 1 below.

Table 1: Adverse Reactions Reported in Mebendazole-Treated Subjects from 39 Clinical Trials^*

Clinical Studies With Mebendazole Chewable 500 mg Tablet

The safety profile of mebendazole chewable 500 mg tablets administered as a single dose was evaluated in 677 pediatric subjects aged 1 to 16 years and in 34 adults. The safety profile was consistent with the known safety profile of mebendazole.

Postmarketing Experience

The following adverse reactions have been identified in adult and pediatric patients postmarketing with mebendazole formulations and dosages other than the VERMOX™ CHEWABLE 500 mg tablet. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Table 2: Adverse Reactions Identified During Postmarketing Experience with Mebendazole^*

Drug Interactions for Vermox

Concomitant use of mebendazole and metronidazole should be avoided [see WARNINGS AND PRECAUTIONS].

Warnings for Vermox

Included as part of the PRECAUTIONS section.

Precautions for Vermox

Risk Of Convulsions

Convulsions have been reported in infants below the ageof 1 year during post-marketing experience with mebendazole [see ADVERSEREACTIONS].

Hematologic Effects

Agranulocytosis and neutropenia have been reported withmebendazole use at higher doses and for more prolonged durations than isrecommended for the treatment of soil-transmitted helminth infections. Monitorblood counts if VERMOX™ CHEWABLE is used at higher doses or for prolongedduration.

Metronidazole Drug Interaction And Serious Skin Reactions

Stevens-Johnson syndrome/toxic epidermal necrolysis(SJS/TEN) have been reported with the concomitant use of mebendazole and metronidazole.Avoid concomitant use of mebendazole and metronidazole.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

In carcinogenicity tests of mebendazole in mice and rats,no carcinogenic effects were seen at doses as high as 40 mg/kg (0.4 to 0.8-foldthe MRHD, based on mg/m²) given daily over two years. No mutagenic activity wasobserved with mebendazole in a bacterial reverse gene mutation test.Mebendazole was mutagenic in the absence of S-9 when tested using a continuous(24 hour) treatment incubation period in the mouse lymphoma thymidine kinaseassay. Mebendazole was aneugenic in vitro in mammalian somatic cells. In the invivo mouse micronucleus assay, orally administered mebendazole induced anincreased frequency of micronucleated polychromatic erythrocytes with evidencesuggestive of aneugenicity. Doses up to 40 mg/kg in rats (0.8-fold the MRHD,based on mg/m²), given to males for 60 days and to females for 14 days prior togestation, had no effect upon fetuses and offspring.

Use In Specific Populations

Pregnancy

Risk Summary

The available publishedliterature on mebendazole use in pregnant women has not reported a clearassociation between mebendazole and a potential risk of major birth defects ormiscarriages [see Data]. There are risks to the mother and fetusassociated with untreated helminthic infection during pregnancy [seeClinical Considerations].

In animal reproduction studies,adverse developmental effects (i.e., skeletal malformations, soft tissuemalformations, decreased pup weight, embryolethality) were observed whenmebendazole was administered to pregnant rats during the period oforganogenesis at single oral doses as low as 10 mg/kg (approximately 0.2-foldthe maximum recommended human dose (MRHD)). Maternal toxicity was present atthe highest of these doses [see Data].

The estimated background riskof major birth defects and miscarriage for the indicated populations isunknown. All pregnancies have a background risk of birth defect, loss, or otheradverse outcomes. In the U.S. general population, the estimated background riskof major birth defects and miscarriage in clinically recognized pregnancies is2-4% and 15-20%, respectively.

Clinical Considerations

Disease-Associated Maternal And/OrEmbryo/Fetal Risks

Untreated soil-transmittedhelminth infections in pregnancy are associated with adverse outcomes includingmaternal iron deficiency anemia, low birth weight, neonatal and maternal death.

Data

Human Data

Several published studies, including prospectivepregnancy registries, case-control, retrospective cohort, and randomizedcontrolled studies, have reported no association between mebendazole use and apotential risk of major birth defects or miscarriage. Overall, these studiesdid not identify a specific pattern or frequency of major birth defects withmebendazole use. However, these studies cannot definitely establish the absenceof any mebendazole-associated risk because of methodological limitations, includingrecall bias, confounding factors and, in some cases, small sample size orexclusion of first trimester mebendazole exposures.

Animal Data

Embryo-fetal developmental toxicity studies in ratsrevealed no adverse effects on dams or their progeny at doses up to 2.5mg/kg/day on gestation days 6-15 (the period of organogenesis). Dosing at ≥ 10 mg/kg/day resulted in a lowered body weight gain and a decreasedpregnancy rate. Maternal toxicity, including body weight loss in one animal andmaternal death in 11 of 20 animals, was seen at 40 mg/kg/day. At 10 mg/kg/day,increased embryo-fetal resorption (100% were resorbed at 40 mg/kg/day),decreased pup weight and increased incidence of malformations (primarilyskeletal) were observed. Mebendazole was also embryotoxic and teratogenic inpregnant rats at single oral doses during organogenesis as low as 10 mg/kg(approximately 0.2-fold the MRHD, based on mg/m²).

In embryo-fetal developmental toxicity studies in micedosed on gestation days 6-15, doses of 10 mg/kg/day and higher resulted indecreased body weight gain at 10 and 40 mg/kg/day and a higher mortality rateat 40 mg/kg/day. At doses of 10 mg/kg/day (approximately 0.1-fold the MRHD,based on mg/m²) and higher, embryo-fetal resorption increased (100% at 40mg/kg) and fetal malformations, including skeletal, cranial, and soft tissueanomalies, were present. Dosing of hamsters and rabbits did not result inembryotoxicity or teratogenicity at doses up to 40 mg/kg/day (0.6 to 1.6-foldthe MRHD, based on mg/m²).

In a peri-and post-natal toxicity study in rats,mebendazole did not adversely affect dams or their progeny at 20 mg/kg/day. At40 mg/kg (0.8-fold the MRHD, based on mg/m²), a reduction of the number of livepups was observed and there was no survival at weaning. No abnormalities werefound on gross and radiographic examination of pups at birth.

Lactation

Risk Summary

Limited data from case reports demonstrate that a smallamount of mebendazole is present in human milk following oral administration.There are no reports of effects on the breastfed infant, and the limitedreports on the effects on milk production are inconsistent. The limited clinicaldata during lactation precludes a clear determination of the risk of VERMOX™CHEWABLE to a breastfed infant; therefore, developmental and health benefits ofbreastfeeding should be considered along with the mother's clinical need forVERMOX™ CHEWABLE and any potential adverse effects on the breastfed infant fromVERMOX™ CHEWABLE or from the underlying maternal condition.

Pediatric Use

The safety and effectiveness of VERMOX™ CHEWABLE 500 mgtablets have been established in pediatric patients 1 to 16 years of age. Useof VERMOX™ CHEWABLE 500 mg tablets in children is supported by evidence fromadequate and well-controlled studies of VERMOX™ CHEWABLE 500 mg tablets [see ClinicalStudies].

The safety and effectiveness of mebendazole, includingVERMOX™ CHEWABLE have not been established in pediatric patients less than oneyear of age. Convulsions have been reported with mebendazole use in this agegroup [see WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS].

Geriatric Use

Clinical studies of mebendazole did not includesufficient numbers of subjects aged 65 and older to determine whether theyrespond differently from younger subjects.

Adult Use

The safety and effectiveness of VERMOX™ CHEWABLE 500 mgtablets have been established in adults for the treatment of gastrointestinalinfections by T. trichiura and A. lumbricoides. Use of VERMOX™CHEWABLE 500 mg tablets in adults for these indications is supported byevidence from an adequate and well-controlled trial in pediatric patients ages1 to 16 years [see Clinical Studies], safety data in adults [see ADVERSEREACTIONS], pharmaco*kinetic data in adults [see CLINICAL PHARMACOLOGY],and the evidence from published literature.

Overdose Information for Vermox

In patients treated at dosages substantially higher than recommended or for prolonged periods of time, the following adverse reactions have been reported: alopecia, reversible transaminase elevations, hepatitis, agranulocytosis, neutropenia, and glomerulonephritis.

Symptoms And signs

In the event of accidental overdose, gastrointestinal signs/symptoms may occur.

Treatment

There is no specific antidote.

Contraindications for Vermox

VERMOX™ CHEWABLE is contraindicated in persons with a known hypersensitivity to the drug or its excipients.

Clinical Pharmacology for Vermox

Mechanism Of Action

Mebendazole, a benzimidazole, is an anthelmintic [see Microbiology].

Pharmaco*kinetics

Absorption

Following oral administration of VERMOX™ CHEWABLE 500 mg tablet, the majority of the dose remains in the gastrointestinal tract where it exerts an anthelmintic effect locally. Dosing the VERMOX™ CHEWABLE 500 mg tablet with a high fat meal increases the bioavailability of mebendazole. In the clinical studies conducted in pediatric patients with soil transmitted helminth infections, the majority of these patients were administered VERMOX™ CHEWABLE 500 mg tablets with food.

Mean plasma pharmaco*kinetic parameters of mebendazole in healthy adult subjects under fasted and fed conditions are summarized in Table 3.

Table 3: Mean (SD) Plasma Pharmaco*kinetic Parameters After a Single VERMOX™ CHEWABLE 500 mg Dose in Healthy Adult Subjects (n=16) Under Fasted and Fed (High-fat Meal) Conditions

Distribution

The plasma protein binding of mebendazole is 90 to 95%. The volume of distribution is 1 to 2 L/kg, indicating that absorbed mebendazole penetrates areas outside the vascular space.

Metabolism

Orally administered mebendazole is extensively metabolized primarily by the liver. Plasma concentrations of its major metabolites (hydrolyzed and reduced forms of mebendazole) are higher than those of mebendazole. Impaired hepatic function, impaired metabolism, or impaired biliary elimination may lead to higher plasma levels of mebendazole.

Elimination

Mebendazole, the conjugated forms of mebendazole, and its metabolites likely undergo some degree of enterohepatic recirculation. The apparent elimination half-life after an oral dose ranges from 3 to 6 hours in most patients. Less than 2% of orally administered mebendazole is excreted in urine and the remainder in the feces as unchanged drug or its metabolites.

Specific Populations

Pediatric

Based on a limited number of blood samples, the pharmaco*kinetic results following single-dose administration of a 500 mg mebendazole chewable tablet to pediatric patients (age 1 to 16 years) with single or mixed infections of T. trichiura and/or A. lumbricoides indicated that children aged 1 to 3 years have higher systemic exposure than adults.

Microbiology

Mechanism Of Action

Mebendazole interferes with cellular tubulin formation in the helminth and causes ultrastructural degenerative changes in its intestine. As a result, its glucose uptake and the digestive and reproductive functions are disrupted, leading to immobilization, inhibition of egg production and death of the helminth.

Antimicrobial Activity

Mebendazole is active against:

Ascaris lumbricoides
Trichuris trichiura

Resistance

There is a potential for development of resistance to mebendazole. The mechanism of resistance to mebendazole is likely due to changes of beta-tubulin protein, which reduces binding of mebendazole to beta-tubulin; however, the clinical significance of this is not known.

Clinical Studies

The efficacy of VERMOX™ CHEWABLE 500 mg tablets was evaluated in a double-blind, randomized, placebo controlled trial conducted in Africa in 295 pediatric patients between the ages of 1 year to 16 years of age with A. lumbricoides and/or T. trichiura infections. Patients were stratified by worm type and randomized to receive either VERMOX™ CHEWABLE 500 mg tablet (N=149) or placebo (N=146) at the baseline visit (double-blind period). After the 19 day double-blind period, all subjects received a single VERMOX™ CHEWABLE 500 mg tablet (open-label period).

Clinical cure was defined as zero egg count (A. lumbricoides and/or T. trichiura) at the end of the double-blind period (Day 19) in patients with positive egg count for the respective worm(s) at baseline. Patients with missing stool sample at Day 19 were considered not cured (Table 4).

Table 4: Clinical Response at the End of the Double-Blind Period (Day 19) for A.lumbricoides and T. trichiura

In patients treated with VERMOX™ CHEWABLE 500 mg, egg count reduction rate at the end of the double-blind period (Day 19) in patients with A. lumbricoides and/or T. trichiura was statistically significant (p<0.001) compared to placebo, 100% compared to 30.0% for A. lumbricoides, respectively, and 81.2% compared to 27.4% for T. trichiura, respectively.

Patient Information for Vermox

Advise patients that:

• VERMOX™ CHEWABLE tablet must be chewed completely before swallowing. For patients who have difficulty chewing the tablet, VERMOX™ CHEWABLE tablet can be turned into a soft mass with semi-solid consistency by adding 2 mL to 3 mL of drinking water to a spoon then placing the tablet into the water, which can then be swallowed. [see DOSAGE AND ADMINISTRATION]
• VERMOX™ CHEWABLE tablet must not be swallowed whole. [see DOSAGE AND ADMINISTRATION]
• VERMOX™ CHEWABLE tablet can be taken with or without food. [see DOSAGE AND ADMINISTRATION]
• Taking VERMOX™ CHEWABLE tablet and metronidazole together may cause serious skin reactions and should be avoided. [see WARNINGS AND PRECAUTIONS]