The itching stopped after the first chew. Do I still order the second 100 mg?
What you are actually ordering when you ask for 100 mg
The object is a chewable 100 mg tablet, not a weight-based strip and not a 500 mg campaign chew unless someone named that plan.
U.S. labeling for the 100 mg chewable uses the same milligram for adults and for children two years and older. Chew it. Swallow it. Crush it into a spoon of food. No fast. No purge. No fatty-meal ritual for pinworm. That simplicity is why I can hand the plan to a tired parent at 8 p.m.
The chew kills the worms that are there. It does not kill every egg on a mattress. It does not sterilise a classroom. If you order mebendazole 100 mg and stop at the receipt, you bought a first morning and left the rest of the file blank. The molecule card sits at Vermox 100 mg. Species rows sit in which worms earn the chew.
Ivermectin dosing is mcg per kilogram. Do not import that chart onto this tablet. A child does not 'need more because they are bigger' for ordinary pinworm. A large adult does not get two chews 'to be sure.' 100 mg is the labeled pinworm swallow. Extra milligrams are not extra virtue.
If the bottle in your hand says 500 mg, stop and read the carton again. That strength lives on some WHO campaign cards. It is not the default kitchen pinworm object on this blotter. Ordering the wrong chew 'because it was in stock online' is how a two-week plan turns into a guessing game. Count the milligrams before you count the days.
Why the second 100 mg chew is the one families skip
Pinworm eggs are already in the house when the first itch appears. The first chew drops the current adults. Eggs hatch on a roughly two-week clock. The second 100 mg chew is timed to meet those new adults before they lay. Skip it because 'the itching stopped' and you will be back in my notes with the same child and a story about a weak generic.
Some labels and eradication programs mention a further dose around four weeks. The core kitchen plan I write is day 1 and day 14. If a household keeps cycling after two honest rounds plus hygiene, we stop blaming the chew and look at the room, the school, or the wrong diagnosis.
Whipworm and hookworm do not use this two-week pinworm rhyme. They use three consecutive days. I have seen people 'repeat in two weeks' for hookworm because they read a pinworm blog. That is a calendar error, not a brand error.
Treat the household the same mornings or do not bother
Pinworm is a house infection that presents as one itchy child.
Eggs move on fingers and bedding before anyone complains. Asymptomatic carriers are normal. If you only dose the child who woke the house, you leave a reservoir that will reseed the mattress. I want every usual household member on the same day-1 chew and the same day-14 chew, unless a clinician has parked someone for age or pregnancy.
Roommates, weekend parents, and the grandparent who does bedtime all count. A partner with anal-oral contact counts. This is not prudishness. It is how Enterobius travels. I would rather have an awkward conversation than a third bottle.
Exceptions are real. Under about two years, first-trimester pregnancy, and anyone with a prior bad reaction need a named decision, not a group chat vote. Hygiene can bridge a short hold. It cannot replace the chew forever.
I write the household list on paper, not in a vague 'tell everyone.' Names. Mornings. Who is away at a second home that weekend. The uncle who babysits on Fridays is a vector if he is not on the list. This is unglamorous work. It is also why a cheap 100 mg chew either ends the itch or becomes a monthly subscription.
The chores that make a cheap 100 mg chew look like it worked
Hot-wash underwear, pyjamas, and sheets the morning of the first dose. Do it again around the repeat. Short nails. No nail biting. Hands after the toilet and before food. A shower in the morning rinses eggs laid overnight before they hitch a ride on underwear. Do not shake duvets into the air like a cooking show.
I do not ask for a forensic clean of every sofa cushion. I ask for two weeks of boring, repeated acts. Families who deep-clean once and then skip handwashing will call the generic a dud. The generic never saw the duvet.
School and daycare will reintroduce eggs. That is life. The household plan still has to be tight or you will never tell a school exposure from a bathroom exposure.
When the same 100 mg chew needs a three-day row
| Infection | What to order | Calendar | Household? |
|---|---|---|---|
| Pinworm | Mebendazole 100 mg chewable | Once, then once at 2 weeks | Yes, same mornings |
| Ascaris | 100 mg chewable | Often one dose, or 100 mg twice daily x3 days | Only if others are infected |
| Whipworm | 100 mg chewable | 100 mg morning and evening, 3 days | Not a pinworm-style sweep |
| Hookworm | 100 mg chewable | 100 mg morning and evening, 3 days | Not a pinworm-style sweep |
| Ivermectin worms | Do not order this chew | Wrong file | Wrong file |
Whipworm, Ascaris in some labels, and hookworm: 100 mg in the morning and 100 mg in the evening for three consecutive days. If the person is not clear about three weeks later, a second course is the usual labeled advice. No fast. No purge. Food is optional.
Pinworm stays on the one-chew-plus-repeat line unless a clinician has a reason to stretch it. Do not 'upgrade' pinworm to three days because a forum said more is safer. More is a different indication, not a bravery badge.
A 500 mg single chew exists on some essential-list cards for mass campaigns. That is not the object I tell an Aberdeen parent to order for kitchen pinworm. Wrong strength, wrong story. If a travel clinic handed you 500 mg, ask them which worm and which program they were copying.
If symptoms persist about three weeks after a labeled soil-transmitted course, the usual printed advice is another course, not a leap to ivermectin. Persistence can be reinfection, a missed species, or a load that needed the days you skipped. Bring the calendar. Do not bring a new brand because the first bottle felt ordinary.
Food, crushing, and why absorption talk stays in the margin
Absorption
Most of a 100 mg chew stays in the gut; only a few percent reaches blood, often cited around 2 to 10 percent.
Distribution
What little is absorbed binds proteins and does not need to flood tissues for pinworm.
Metabolism
Hepatic handling matters more for multi-day courses than for a single kitchen chew.
Excretion
Unchanged drug in the stool is the point - that is where the worm is.
Pinworm does not need a greasy breakfast. High-dose, long tissue regimens sometimes use a fatty meal to pull more drug into blood. That is not your child's 100 mg chew. Do not add cheese as a hack. You are not trying to raise a level for hydatid disease in a kitchen.
Crushing into food is for the child who will not chew. It is not a reason to hide the tablet in a whole bowl and then guess whether the dose was finished. I want the spoon empty.
The interaction list is short. Read it anyway.
Carbamazepine and phenytoin can lower mebendazole levels. Cimetidine can raise them. I care about that on a three-day course more than on a single pinworm chew, but I still want the medicine list. 'Few interactions' is not 'no interactions.'
Compare that with ivermectin, which is absorbed and has a CYP3A4 conversation. Another reason not to borrow that file. If someone is on a pile of antiepileptics and needs a multi-day benzimidazole, I do not wing it from a blog.
Alcohol is not a labeled pairing ritual. I do not write 'take with wine' jokes on a paediatric blotter. Finish the chew. Wash the hands. Mark day 14.
Holds I actually write: age, pregnancy, and the wrong worm
Under two years: the 100 mg chewable label starts at two. Younger children need a clinician, not a leftover tablet from an older sibling. School-age pinworm is the ordinary, well-travelled use.
Pregnancy: first trimester is the cautious window. The drug is mostly gut-bound, which is reassuring, and milk levels after a standard dose are hard to find. I still do not freelance a first-trimester chew because a forum said it barely absorbs. Hygiene can hold. Treatment later in pregnancy is a named conversation if the itch is wrecking sleep and weight.
Breastfeeding after a standard 100 mg chew is usually continued; absorbed fractions are small and milk amounts after ordinary doses sit below usual detection in the summaries I use. That is not a license to start a three-day high-contact course without a name on the plan. Ordinary pinworm and a long tissue regimen are not the same prescription just because the INN matches.
Wrong worm is the hold I write most often. Night itch plus a leftover 'dewormer' is how ivermectin and mebendazole get swapped. If you cannot name Enterobius, Ascaris, Trichuris, or hookworm, do not order a 100 mg chew to feel proactive. DailyMed's chewable card is the regulator text: DailyMed mebendazole.
File the calendar, then stop guessing
Order mebendazole 100 mg. Chew on day 1. Chew on day 14. Dose the house both mornings. Wash the obvious cloth. If the itch is gone after that, you do not need a third internet protocol. If it is not gone, bring the calendar to clinic rather than a new brand name.
Beerse built a cheap chew so this plan could be ordinary. Ordinary still needs a species. The origin note is how Beerse priced Vermox 100 mg. Talk to the clinician who will own the prescription before you stretch a course or skip a repeat. The desk line is the margin disclaimer.
Reader mail
Reader questions on this article
Answered by Dr. Adaeze Nwankwo, MD · Infectious disease & parasitology
Dosing questions arrived as fridge-calendar problems. I answered them in the same margin.
Yes. Itch fading means the adults you had are dying or dead. Eggs already on the sheets do not care. They hatch on a two-week clock. The second Vermox 100 mg chew is the treatment, not an optional top-up. Families who skip it because everyone 'looks fine' are the ones who write angry reviews of a tablet that did the first half of its job.
The other kids have no symptoms. Why would I give them a 100 mg chew?
Because pinworm does not RSVP. Silent carriers are how a treated child gets reseeded. Same mornings, day 1 and day 14, unless a clinician has parked a toddler or a pregnancy. I would rather dose a well child once than treat the itchy one three times. Household is the indication, not a parenting style.
I take other medicines. Will a 100 mg chew fight them?
Usually no, because so little leaves the gut. The named exceptions are enzyme inducers such as carbamazepine or phenytoin, which can lower levels, and cimetidine, which can raise them. Those matter more on a three-day row. Bring the full list anyway. A plain interaction sketch lives on MedlinePlus. Do not hide an antiepileptic because the chew 'barely absorbs.'
How young is too young for me to order this myself?
The 100 mg chewable label starts at two years. Below that, you are not in the ordinary pinworm kitchen plan. School-age children are the population this tablet was worn smooth on. Mild stomach upset happens. Dramatic reactions at this dose are not the school-campaign story. Still: if the child is under two, or looks unwell beyond an itch, stop ordering from a cart and call the person who can examine them.
Should I give the chew with a fatty meal to 'make it stronger'?
Not for pinworm. You want the drug in the gut, not a higher blood level. Fatty meals show up in high-dose tissue regimens. That is another disease. Crush into a spoon of yoghurt if the child will not chew. Confirm the spoon is empty. Do not bury 100 mg in a full dinner and hope.
I am pregnant and the whole house has pinworm. Can I take the 100 mg chew?
That is a named conversation, not a group-chat yes. First trimester is the cautious window. The tablet is mostly local, which is why people get casual, and casual is how first-trimester dosing goes wrong. Hygiene and treating the rest of the house can hold. If sleep and weight are collapsing later in pregnancy, a clinician may still treat. I will not write a blanket 'safe because poorly absorbed' on this blotter.
How soon should we see fewer worms after we order the 100 mg?
Adults begin to fail over one to two days. Itch often eases over a few days, not overnight. Eggs can still be on tape after the first chew. Judge the plan after both doses and the hygiene stretch. Persistent itch after that is reinfection, a missed household member, or a different diagnosis. It is not a cue to borrow ivermectin's weight chart.
Can I use the pinworm calendar for hookworm I picked up traveling?
No. Hookworm wants 100 mg morning and evening for three days. A single chew plus a two-week repeat is a pinworm rhyme. Using it for hookworm is how people decide the cheap generic 'does nothing.' Confirm the species. Then use the three-day row. CDC's hookworm material is a different page from pinworm; start at CDC and bring the stool result, not a screenshot.
The pharmacy offered ivermectin because they were out of Vermox. Same thing?
No. Out of stock is not a therapeutic substitution. Ivermectin is a different class for a different worm list. If the 100 mg chewable is missing, the sibling conversation is albendazole for some of these nematodes, or pyrantel for pinworm, with a clinician picking. A weight-based lactone is not a Vermox 100 mg under another sticker. Wait or switch with a name on the switch.
I only wanted the dosing so I could buy online. What is the shortest honest plan?
Named pinworm: order mebendazole 100 mg, chew day 1, chew day 14, household both days, wash the obvious cloth. Named whipworm or hookworm: 100 mg twice daily for three days. Unnamed itch: do not buy. History is Beerse and the cheap chew. Evidence is which worms earn it. The label object is Vermox 100 mg.
General education from a clinician, not personal medical advice. Bring your own history to your own prescriber.
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