Pinworm (Enterobius vermicularis) is the most common helminth infection in temperate countries, and by a wide margin the most common in children. Ivermectin is effective against it, but it is generally not the first choice — the benzimidazoles have a longer track record in this specific indication and are cheaper and more widely stocked.
The lifecycle is what makes it persistent. Adult female worms migrate out of the anus at night to lay thousands of eggs on the surrounding skin. The eggs cause intense itching; scratching transfers them to fingers and under nails; from there they reach the mouth, bedding, towels, door handles and toys.
Eggs remain viable on surfaces for two to three weeks. This is why a single treatment so often appears to fail: the drug kills the adult worms present but does nothing about the eggs already in the environment, which hatch and restart the cycle.
It is also why the whole household is treated together. Asymptomatic carriage is common, and treating one person while leaving reservoirs untouched produces exactly the cycle of apparent cure and relapse that families find so frustrating.
Ivermectin at the standard 200 mcg/kg is active against pinworm, with studies reporting high cure rates when a second dose is given two weeks after the first.
The second dose is not optional. Like the benzimidazoles, ivermectin does not reliably kill eggs, so the repeat dose exists to eliminate worms that have hatched since the first.
In practice ivermectin tends to be used for pinworm when benzimidazole treatment has failed, when there is a co-existing parasitic infection that ivermectin also covers, or where mebendazole is unavailable — which has been an intermittent problem in several markets.
| Drug | Typical adult dose | Repeat | Notes |
|---|---|---|---|
| Mebendazole | 100 mg single dose | After 2 weeks | Long-standing first line; poorly absorbed, so acts locally in the gut |
| Albendazole | 400 mg single dose | After 2 weeks | Equally effective; better absorbed |
| Pyrantel pamoate | 11 mg/kg single dose | After 2 weeks | Available without prescription in many countries |
| Ivermectin | 200 mcg/kg single dose | After 2 weeks | Effective; usually reserved for failure or co-infection |
Medication removes the worms. Hygiene removes the eggs, and without the second half the first half rarely holds.
On treatment day and for the following two weeks: wash all bedding, nightwear and towels in hot water; keep fingernails short and discourage nail-biting; bathe or shower in the morning to remove eggs laid overnight; wash hands thoroughly after using the toilet and before meals; damp-dust and vacuum bedrooms rather than sweeping, which sends eggs airborne.
Treat every household member on the same day, whether or not they have symptoms. This single step is the difference between resolution and a cycle that runs for months.
GMP-certified human formulations — tablets and 1% cream. Never veterinary products. Most USA orders ship within 1–7 business days, with tracking on every order.
View products and pricingYes. At 200 mcg/kg it is effective against pinworm, with high cure rates when a second dose follows two weeks later. It is generally not first line, since mebendazole and albendazole have a longer track record in this indication.
Because eggs survive on bedding, clothing, nails and surfaces for two to three weeks, and no medication kills eggs. Without treating the whole household simultaneously and doing thorough laundry and hand hygiene, the cycle simply restarts.
Yes, about two weeks after the first, whichever drug you use. The first dose kills the adult worms present; the second kills those that have hatched from eggs since.
Yes, on the same day, symptoms or not. Asymptomatic carriage is common, and treating one person while others remain infected guarantees reinfection.
Intense night-time anal itching is the classic sign, and adult worms are sometimes visible around the anus a few hours after sleep. The standard confirmation is the tape test: clear tape pressed to the perianal skin first thing in the morning, before washing, then examined under a microscope.