A single chew cleared my child's pinworm. Why would hookworm need three days of the same tablet?
Reviews that skip the species are half a note
The wrong question is whether mebendazole 'works.' The right one is which worm, for how many days.
One tubulin target. Four common gut nematodes. Four different amounts of drug actually reaching the worm. Pinworm and Ascaris sit in the lumen and meet a 100 mg chew cleanly. Whipworm buries its head in colonic mucosa. Hookworm clamps the small bowel and feeds on blood. Same tablet. Cure rates that run from the mid-nineties down to the teens if you only give one dose.
I will not write a glowing review of cheap mebendazole 100 mg until someone names the parasite. A parent who cured pinworm with one chew will tell a neighbour it 'always works.' That neighbour may have hookworm from a trip and a single tablet that barely dented the load. The chemistry did not fail. The species did not earn a one-chew plan.
Labeled uses on the U.S. 100 mg chewable are enterobiasis, trichuriasis, ascariasis, and the two common hookworms. That is the whole invitation list. Tapeworms, flukes, Strongyloides, Onchocerca, and scabies do not get a seat because a search called everything a worm. The molecule card is Vermox 100 mg. The calendar is order 100 mg, then repeat.
Pinworm is the worm that actually earns a single chew
Enterobius vermicularis is the kitchen presentation: nocturnal anal itch, restless sleep, a child who keeps scratching, eggs on tape or on the perianal skin. A single Vermox 100 mg chewable clears the adults in most people. Cure figures in the overviews sit around 90 to 95 percent when the schedule is respected. That is a real win. I still do not call it a one-and-done medicine.
Eggs survive the first chew. They hatch over about two weeks. The second 100 mg chew intercepts the next adults before they lay. Treat the whole household the same morning, symptomatic or not. Silent carriers hand the itch back to the child you just treated. Reviews that stop at 'one tablet' are the reason families bounce.
Hygiene is not optional colour. Morning shower before dressing, short nails, hot wash of nightclothes and sheets, hands after the toilet. The drug kills worms. It does not bleach the duvet. CDC's clinical overview is the public card I point to: CDC pinworm overview.
Pyrantel pamoate is the over-the-counter rival some families already have. It can clear pinworm on a similar two-dose rhythm. I do not fight a finished pyrantel course if the household and the laundry were honest. I do fight the habit of stacking pyrantel, a leftover ivermectin strip, and a Vermox 100 mg chew in the same weekend because each review promised a different 'complete kill.' Pick one labeled plan and finish it.
Ascaris is the soil worm the 100 mg chew likes
Roundworm sits in the lumen. The tablet can reach it without a three-day argument.
Ascaris lumbricoides is the soil-transmitted helminth with the cleanest single-dose story. A 100 mg chew, or in some programs a 500 mg chew, produces cure rates near 95 percent because the adult lives where the drug lives. If you only remember one 'yes' besides pinworm, remember this one.
Heavy loads can still make a clinician nervous. A slow kill in a packed gut has, rarely, been followed by migration trouble. That is a specialist problem, not a reason to withhold a labeled course from an ordinary infection. It is a reason not to treat a guessed 'worm' at home when the person is febrile, obstructed, or passing a startling number of adults.
Do not export the Ascaris smile onto whipworm. Same class. Same chew. Different anatomy. I have watched that export waste a week.
Mixed infections are common in endemic stool. A child can carry Ascaris and Trichuris together. The 100 mg chew that 'cured the roundworm' can leave whipworm sitting there, and a parent will call the tablet a liar. The tablet did the job it was given for one species. The second species wanted days. That is why I ask for a name, or at least a travel-and-stool story, before I write a one-chew review into a chart.
Whipworm does not earn a one-chew review
Trichuris trichiura keeps its head in the colonic wall. A single 100 mg chew often cures only about a third of infections - the 30 to 40 percent band shows up again and again. That is not a rounding error. It is contact time. The labeled rescue is 100 mg morning and evening for three consecutive days. Prolonged lumen levels, better chance.
Mass programs sometimes still give one dose because coverage beats perfection when you are treating a school, not a named patient. I will not pretend those two goals are the same. If a person in front of me has documented whipworm, they get the three-day row. If a ministry is deworming a district, they may accept a weaker single-dose bargain. Write the setting in the margin or you will quote the wrong number.
Hookworm is why I distrust one-chew testimonials
Ancylostoma duodenale and Necator americanus attach and drink. A single 100 mg chew cures on the order of 15 percent. That number should end the 'I took one pill on holiday' story. The labeled individual course is again 100 mg twice daily for three days. Even a weak single dose can cut egg output, which is why programs still use it. Cutting load is not the same as clearing a symptomatic person.
Hookworm is also an anaemia story. If the only outcome you track is 'itch gone,' you will miss the reason the tablet was offered. I want a haemoglobin in the file when the travel or the exposure fits. The chew is not an iron tablet. It is one piece of a blood-loss problem.
Albendazole's single-dose hookworm numbers look better. That is a fair sibling comparison. It is not a reason to call mebendazole useless. Give it the days the label printed.
Travel clinics sometimes hand out a single 'dewormer' at the end of a trip as if species were a formality. I ask what they think they treated. If the answer is 'whatever is in the soil,' I do not file a one-chew testimonial. I file a stool, a haemoglobin if the story fits, and a three-day row when hookworm is the named bet. Souvenir tablets are how 15 percent cure rates become one-star reviews.
Ivermectin's worms do not earn this chew
Shared slang is not a shared spectrum.
Ivermectin is the molecule people reach for when they hear 'parasite' after 2020. Its labeled and programmatic strengths sit on onchocerciasis, strongyloidiasis, and some ectoparasites. Those are not mebendazole's job. A Vermox 100 mg chew will not run a river-blindness campaign and will not be my first tablet for Strongyloides. Different channel, different absorption, different file.
The reverse error is just as common. Someone with pinworm reads an ivermectin blog and orders a weight-based lactone because it sounds stronger. Stronger is not the metric. Pinworm earns a 100 mg benzimidazole chew, a day-14 repeat, and a household. Ivermectin can kill Enterobius in some reports. That does not make it the kitchen plan on this blotter.
Tapeworms and flukes are another miss. Occasional older monographs mention taeniasis. I do not treat a tapeworm with a pinworm chew and call it evidence-based. Name the worm. Then pick the drug that was studied for that worm.
What a cheap 100 mg chew costs you against the rivals
| Parasite | Vermox 100 mg once | Better mebendazole plan | Ivermectin note |
|---|---|---|---|
| Pinworm | High if you repeat at 2 weeks | Household same morning | Not the kitchen first pick |
| Ascaris | High, about 95 percent | Single chew often enough | Also high; different file |
| Whipworm | Low, about 30-40 percent | 100 mg twice daily, 3 days | Weak alone |
| Hookworm | Low, about 15 percent | 100 mg twice daily, 3 days | Poor alone |
| Strongyloides / oncho | Not the indication | Do not file this chew | That is ivermectin's list |
Albendazole is the benzimidazole sibling. Single-dose hookworm: albendazole usually wins. Ascaris: both high. Whipworm: both weak as a single swallow, both better as a longer contact. Pinworm: both fine if you repeat. Programs pick whatever the tender delivered. A kitchen in Aberdeen picks what the local pharmacy can actually put in a hand.
Ivermectin in a comparison table looks strong on Ascaris and weak alone on hookworm and whipworm. Combinations exist in trial literature. That is research, not a reason to stack two antiparasitics because an online review said 'broader.' I stack when a specialist names a dual infection. I do not stack because a cart offered a bundle.
Mass deworming results are not your child's review
Most mebendazole on earth is swallowed in a schoolyard, not after a tape test. Programs buy egg-reduction and a safer community load. They accept reinfection. They accept that a single 500 mg chew will miss some whipworm and most hookworm as a 'cure.' The human downstream - height, test scores, wages - is still argued in the trial literature. The worm-load drop is not argued. WHO policy still sits on benzimidazoles.
A symptomatic household is a different review. I want species, a 100 mg schedule that matches that species, and a follow-up if symptoms persist after the labeled course. Quoting a district-level anaemia paper to justify one leftover chew in a suitcase is how evidence gets abused.
I also file the opposite abuse: a parent who read a sceptical deworming essay and then refuses a labeled 100 mg chew for documented pinworm because 'the long-term trials were messy.' Those trials asked about height and wages after school campaigns. They did not ask whether Enterobius still itches at 2 a.m. Kitchen evidence and program evidence are two rows. Do not cross them to avoid a cheap tablet.
Peer-line: if the only number you remember is '95 percent,' ask which worm. If the only brand you remember is Vermox, ask whether the worm on the list is even invited. Then talk to the person who will put their name on the prescription before you change a plan. The hold is on the margin disclaimer.
Reader mail
Reader questions on this article
Answered by Dr. Adaeze Nwankwo, MD · Infectious disease & parasitology
Species questions landed in the margin after this evidence file. I answered them as I would on the ward.
Exposure. Pinworm sits in the lumen and meets a Vermox 100 mg chew. Hookworm is attached and feeding. One swallow leaves most of those adults in place - cure around 15 percent if you stop there. The label's individual plan is 100 mg morning and evening for three days. Same molecule, different contact time. I would not let a pinworm success story write a hookworm prescription.
We keep getting pinworm back. Is the 100 mg chew too weak?
Usually the chew worked and the house did not. Eggs on hands, toys, and sheets hatch after the first dose. Repeat the 100 mg chew at two weeks and treat every household member the same mornings. Cut nails. Wash the night clothes hot. If you only dosed the itchy child, you treated a symptom and left the reservoir. CDC walks that loop at the pinworm overview.
Should I just buy albendazole because hookworm reviews look better?
For a single-dose hookworm comparison, albendazole often wins. For a three-day mebendazole course the gap narrows. For pinworm I still prefer the 100 mg chew we can actually give a child without a food ritual. Buy the drug that matches the named worm and the course you will finish. A better-looking table is not a reason to switch mid-household.
Whipworm cure rates look embarrassing. Why is it still on the label?
Because the three-day row is a different medicine than the one-chew row. Single-dose whipworm is weak. 100 mg twice daily for three days is the labeled attempt to give the embedded head enough contact. Programs may still use one dose for coverage. Your kitchen is not a program. Finish the days or do not claim the evidence.
If one dose does not cure hookworm, why do school campaigns still use it?
They are buying a lower community egg count, not a personal cure letter. One cheap chew across a thousand children still cuts transmission. A pale, tired traveller in clinic is not a thousand children. That person gets the three-day course, iron if needed, and a follow-up. Do not quote a ministry protocol to under-treat a named patient.
How settled is the long-term 'deworming makes kids richer' claim?
Worms down, safety at scale: settled enough that I will not reopen it in a consult. Height, cognition, wages years later: mixed trials, real debate. I will not sell a Vermox 100 mg chew as an exam-score tablet. I will sell it as a worm tablet. WHO still recommends preventive benzimidazole chemotherapy; the policy page is at WHO.
Can I use this chew for every worm a travel clinic mentioned?
No. Labeled 100 mg uses are pinworm, Ascaris, whipworm, and hookworm. Not tapeworm as a first plan. Not flukes. Not Strongyloides. Not onchocerciasis. Not 'a parasite I read about.' If the clinic named a different genus, we file a different drug. Ivermectin's list is the usual mix-up. Keep it off this blotter.
Is a chewable weaker than a swallowed tablet of the same 100 mg?
No. The gut sees the dose either way. Chew, swallow, or crush into food - the label allows all three. Efficacy is species plus milligrams plus days, not mouthfeel. I like the chew because children finish it. That is adherence, not potency theatre.
Where is the molecule file if I only wanted the evidence so I could order the right strength?
Strength on this site is the 100 mg chewable. Evidence tells you whether your worm earned that chew and whether one day or three days belong on the card. History is how Beerse priced it. The calendar is repeat in two weeks. The label card is Vermox 100 mg. Order after the worm has a name.
General education from a clinician, not personal medical advice. Bring your own history to your own prescriber.
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