Mebendazole 100 mg Chewable: Pinworm Cost After One Chew

One 100 mg chewable is the start of pinworm treatment, not the finish

The Emverm 100 mg chewable is a peach, round, unscored tablet. Adults and children 2 years and older take one tablet once for Enterobius vermicularis. That sentence is the entire pinworm row on the US dosing table. It is also the sentence people stop reading.

A single 100 mg dose is aimed at the worms you have now. Pinworm females lay eggs on the skin at night. Those eggs are not a reliable target for the first swallow. Kids scratch, eggs ride under nails, and the next generation hatches on a delay. If you treat the itch and throw the blister pack away, the household often meets the same worm in a fortnight.

CDC's clinical overview is blunt about the repeat. The medicines used for pinworm, including mebendazole 100 mg, kill worms and cannot kill eggs. A second 100 mg is given two weeks later to catch newly hatched adults. That is why this page locks a 2-3 week second dose instead of celebrating a one-tablet cure.

The US tablet label uses a slightly different trigger: if the patient is not cured three weeks after treatment, a second course is advised. Clinics that follow CDC will often just schedule the second 100 mg at two weeks and not wait for a symptom quiz. Both clocks sit in the 2-3 week window. Pick one with the prescriber and write it on the calendar the day you take the first chewable.

Vermox is the older trade name still printed on many non-US leaflets and on older US memories. The current US 100 mg chewable label in DailyMed is Emverm. The INN is mebendazole either way. Do not mix this 100 mg pinworm tablet with overseas 500 mg single-dose chewables used for other worms. Strength first, then the schedule.

Why the two-week repeat exists

Pinworm eggs are the part of the life cycle a 100 mg chewable does not finish. Adult worms in the gut take the hit. Eggs already on perianal skin, pajamas, and bedroom dust do not. Those eggs are small enough to ride a fingernail back to the mouth. The hatch then rebuilds an adult population after the first tablet is gone.

CDC times the second dose at two weeks for that reason. UK threadworm leaflets often say a doctor may ask for a second tablet after two weeks in case of reinfection. US Emverm uses a three-week cure check as the official second-course trigger. If you need one household rule that does not fight those documents, it is 100 mg now and 100 mg again in 2-3 weeks.

Young worms are the stubborn ones in the clinical reviews. That is another way of saying the same egg problem. A tablet that lands while the cohort is still eggs will look like a failure two weeks later even if the first adults died on schedule. The repeat is not an admission that 100 mg is weak. It is an admission that eggs are not worms.

Hygiene has to cover the same two weeks. Morning showers, trimmed nails, washed hands, and hot laundry on underwear and bedding cut the egg load the tablet never sees. CDC notes that control is hard in day care and boarding settings because repeat infection is the norm. Mass treatment of a classroom, repeated in two weeks, is a public-health version of the same clock.

If itching stops on day 2, you still take the second 100 mg. Symptom relief is not a stool certificate. Pinworm diagnosis is often a tape test at night, and families skip the follow-up tape. The calendar dose is cheaper than a second month of scratching. If the cycle keeps returning after two correctly timed 100 mg doses plus laundry, ask about a missed contact, not a stronger fantasy tablet.

What two 100 mg chewables cost at a US counter

Emverm 100 mg chewable, two tablets (first swallow plus the labeled 2-3 week repeat), checked November 2026. Drugs.com price guide lists one 100 mg chewable from $318.46 to $634.44. SingleCare lists about $861.83 cash and $636.29 with a coupon for one chewable blister. US mebendazole is still a high-list brand chewable; pyrantel on the drugstore aisle is the OTC pinworm fork. GoodRx and SingleCare are named here, not used as a row href. Each link is that pharmacy only. Gravix does not dispense. Prescription required. ZIP changes the print.

Pinworm on this page is one 100 mg chewable now and the same 100 mg in two or three weeks. The four store cards therefore ask licensed counters for a two-tablet pair, not a three-day soil-transmitted pack.

US list prices for Emverm are high. The caption cites Drugs.com and SingleCare for one chewable, because that is what those pages publish. Pyrantel on a drugstore shelf is the legal OTC fork if the clinician is treating pinworm and Emverm is not the plan. Links go to the pharmacy, not to a coupon site.

The 3-day morning-and-evening course for the soil-transmitted set

Whipworm, roundworm, and hookworm share one Emverm row. One 100 mg tablet in the morning and one in the evening, for 3 consecutive days. Adults and children 2 years and older use that same map. The tablet may be chewed, swallowed, or crushed and mixed with food. Food is allowed. Fasting is not required. Purging is not required.

That is 600 mg over three days if every dose is taken. It is not a single 100 mg worm pill. Miss the evening dose on day 2 and the 68% whipworm mean cure gets worse. Set alarms. If a child spits a crushed tablet, do not double the next dose unless the prescriber says to. Call and reset the day.

US Emverm still says that if the patient is not cured three weeks after treatment, a second course is advised. For these worms that second course is another 3-day twice-daily block, not a lone tablet. Stool checks, not itch scores, decide cure for Ascaris, Trichuris, and hookworm. Egg counts can fall a lot even when a hard cure is missed, which is why the label prints both figures.

Overseas Vermox 500 mg single-dose chewables are a different product and a different labeled age in some countries. MedlinePlus and GoodRx still mention that 500 mg Vermox presentation for roundworm and whipworm. Do not import that schedule onto an Emverm 100 mg blister and call it close enough. If the bottle says 100 mg, use the 100 mg table.

Mixed infections use the 3-day row when whipworm, Ascaris, or hookworm is in the mix. A pinworm-only house can stay on the single tablet plus 2-3 week repeat. If both are present, the 3-day course covers the soil-transmitted worms; ask whether pinworm still needs its own timed repeat. That is a clinic sentence, not a blog stack of extra 100 mg tablets.

Avoid metronidazole; watch blood counts only when the dose leaves the usual map

Do not pair mebendazole with metronidazole. Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported with that combination. The Emverm warning is an avoid, not a "monitor and see." Flagyl for bacterial vaginosis or a dental abscess has to wait or switch if the worm tablet is in play. Tell both prescribers.

The only contraindication on the label is hypersensitivity to the drug or its excipients. That is a short list. The serious skin reaction with metronidazole still sits in warnings because it is a known pair, not because every rash is SJS. A simple hive still needs a call. Blistering, peeling, or mouth sores need emergency care.

Agranulocytosis and neutropenia are tied to higher doses and longer durations than soil-transmitted helminth schedules. If someone is using mebendazole in that high-dose way, monitor blood counts. Fever during a prolonged course is a lab day, not a "push through the deworming." The ordinary 100 mg pinworm chewable is not that regimen.

Post-marketing, with mixed formulations, also lists anaphylaxis, convulsions, dizziness, hepatitis, abnormal liver tests, glomerulonephritis, angioedema, urticaria, and alopecia. Those reports cannot give a clean frequency. They are a reason to stop and call if the picture is more than a day of gas and loose stool.

Overdose, as far as the label writes it, is gastrointestinal: cramps, nausea, vomiting, diarrhea. There is no specific antidote. Accidental extra 100 mg in a toddler is a poison-control call, not an internet wait. Keep the blister above small hands. Emverm's US pack is often a single tablet in a carton, which is easy to lose and easy for a child to find.

What the label's mean cure table actually shows

Emverm prints one efficacy table from "various studies." Mean cure rates: pinworm 95%, whipworm 68%, roundworm 98%, hookworm 96%. Mean egg reduction: whipworm 93%, roundworm 99%, hookworm 99%. Pinworm has no egg-reduction percentage on that row.

Read whipworm last if you like good news, because 68% is the honest weak cell. A family that treats Trichuris with one leftover pinworm tablet will miss. They need the 3-day twice-daily course and a stool, then the three-week "not cured" clause if eggs persist. Egg reduction of 93% can still leave a person infectious or symptomatic.

Roundworm at 98% cure and 99% egg reduction is why clinicians still reach for a benzimidazole when Ascaris is the isolate. Hookworm at 96% and 99% sits in the same useful band. Those means pool old study methods. They are not a promise that your household is in the 98th percentile.

Safety in the same file is a different sample. Adverse-reaction listing drew on 6276 subjects in 39 trials with mixed formulations and durations, not only today's 100 mg chewable. The common gastrointestinal list is anorexia, abdominal pain, diarrhea, flatulence, nausea, and vomiting. Rash is on the skin line. The file does not print a neat percentage next to each of those words.

If you want the class context against ivermectin, use the antiparasitic comparison. Ivermectin's US tablet job is Strongyloides and Onchocerca, not this pinworm 100 mg chewable. Borrowing ivermectin 3 mg for a tape-test child is usually the wrong molecule.

Most of the 100 mg never needs to be a blood level

After an oral dose, most mebendazole stays in the gut and works there. That is the pharmacokinetic point of a poorly absorbed benzimidazole. Following 100 mg twice daily for 3 days, plasma mebendazole stays at or below 0.03 mcg/mL. The primary 2-amine metabolite stays at or below 0.09 mcg/mL.

A high-fat meal raises how much gets into blood. The label still says the amount left in the gastrointestinal tract is not expected to change in a big way. Emverm can be taken with or without food. If a child eats first, you do not cancel the chewable. If a child takes it on an empty stomach, you do not add a milk chaser for "absorption." The worm is in the lumen.

What little is absorbed is 90-95% protein bound. Volume of distribution is 1-2 L/kg. The liver does the metabolic work. Metabolites, hydrolyzed and reduced, run at higher plasma levels than parent drug and have no anthelmintic activity. Impaired hepatic function, impaired metabolism, or impaired biliary elimination can raise mebendazole levels.

Apparent elimination half-life is 3-6 hours in most people. Less than 2% of an oral dose leaves in urine. The rest leaves in feces as unchanged drug or metabolites. Some enterohepatic recirculation is likely. None of that asks you to time the 100 mg to a creatinine value. It asks you to finish the pinworm repeat or the 3-day pair of daily tablets.

High-dose, long-duration use is a different exposure and a different safety file. Neutropenia, agranulocytosis, hepatitis, alopecia, and glomerulonephritis show up when people push mebendazole well past soil-transmitted schedules. The 100 mg pinworm chewable is not that experiment. Do not invent a cancer-dose calendar from a pinworm blister.

Treat the household when the clutch is shared

Pinworm is a bedroom and bathroom infection. Mayo's patient page says all household members may need treatment at the same time because the worm moves person to person so easily. CDC says the same for families and for institutions. The Emverm label does not write "dose every cousin" as a legal line. Clinicians still treat the cluster because one untreated sleeper restocks the eggs.

Same-day first doses beat a relay. If a child takes 100 mg on Monday and a parent waits until the weekend, the Monday eggs have a fresh host. Book the repeat 2-3 weeks later for everyone who took the first tablet. Do not give a third or fourth 100 mg the next day because someone still itched. Itch can lag dead worms.

Under 2 years is not this tablet's labeled population. Emverm is indicated from age 2. Convulsions have been reported with mebendazole in infants younger than 1 year. A toddler in a crib next to an infected preschooler is a pediatric decision, not a leftover half-tablet from a parent. Pyrantel is the other named option on CDC's list and is sold without a prescription in the US. It still needs its own age and pregnancy check.

School exclusion is usually the wrong fight. UK threadworm guidance says children do not need to stay home once treatment and hygiene are underway. The useful work is simultaneous 100 mg doses, a written 2-3 week repeat, and laundry. Naming the worm in a group chat helps more than keeping a child out of class for a week.

If the diagnosis is actually hookworm or Ascaris, the household script changes. Those worms are not a bedtime tape-test problem. They need the 3-day course below, and contacts are managed by stool and travel history, not by default dosing of every roommate. Wrong worm, wrong calendar.

The worm loses glucose uptake after the tubulin hit

Mebendazole interferes with cellular tubulin formation in the helminth. The gut lining of the worm degenerates at the ultrastructural level. Glucose uptake falls. Digestion and reproduction stall. The worm stops moving, egg production drops, and the helminth dies. That is the microbiology section in one chain, and it is why a luminal drug can work without a high plasma peak.

Activity on the US label is listed by organism: Enterobius vermicularis, Trichuris trichiura, Ascaris lumbricoides, Ancylostoma duodenale, and Necator americanus. If the isolate is something else, this 100 mg chewable may be the wrong tool. Strongyloides is an ivermectin conversation on this site, not a mebendazole default.

Resistance is written as a potential, not a community rate. The likely mechanism is a beta-tubulin change that lowers binding. Clinical meaning is unknown on the label. If a documented Trichuris infection fails a correctly taken 3-day course, the next step is a stool and a specialist, not a silent fourth box of 100 mg tablets.

Chemistry is small next to ivermectin's macrolide. Formula C16H13N3O3, molecular weight 295.29, less than 0.05% soluble in water. The chewable adds cellulose, corn starch, lactose, sodium starch glycolate, magnesium stearate, stearic acid, sodium lauryl sulfate, saccharin, and FD&C Yellow No. 6. Peach color is dye, not flavor proof that a child will like it.

Initial US approval of mebendazole was 1974. Longevity is not a reason to skip the 2-3 week pinworm repeat. The egg clock is older than the tablet.

Chew, crush, or swallow, then keep the 2-3 week date

How you get the 100 mg down is written in one line. Chew it. Swallow it. Or crush it and mix it with food. Supervise a child. UK Vermox leaflets tell you to crush for younger children who cannot handle a whole tablet. Do not hide a dry tablet in a spoon of jam and walk away.

Pregnancy is not a casual extra tablet. Published human data have not shown a clear link to major birth defects or miscarriage. The studies still cannot prove absence of risk. First-trimester exposures were thin in some of them. Animal work in rats and mice found embryo loss and malformations at doses near or below human mg/m2 multiples. Untreated helminths in pregnancy also harm mother and fetus, including iron-deficiency anemia and low birth weight. That pair of facts is why the obstetrician owns the yes or no, not a school-nurse rumor.

Lactation data are limited case reports of small amounts in milk. Effects on milk volume are inconsistent. The label does not give a clean "pump and dump" number. The patient leaflet tells people to talk through feeding before they take the chewable. Do that instead of guessing from a comment thread.

A US fill is a prescription 100 mg chewable. Coupon and telehealth pages will show Emverm at pharmacies, including chains people already use. Vermox as a US product is no longer the bottle you should expect. If a site offers mystery "mebendazole 100 mg" without a prescription trail, treat it as a different supply problem. Pyrantel from a drugstore is the legal OTC fork for some pinworm cases.

Write two dates when the first 100 mg goes in: today, and 2-3 weeks later. Treat the people who share the house if the clinician is treating a cluster. Wash the linens. If the isolate is Ascaris, Trichuris, or hookworm, switch your head to morning and evening for 3 days. If the isolate is Strongyloides or Onchocerca, you are on the wrong page: that is ivermectin 3 mg. More pinworm technique sits in the 100 mg taking guide.