Name the worm before you name the tablet
| If the confirmed target is | First tablet logic | US product note |
|---|---|---|
| O. volvulus microfilariae | Ivermectin ~150 mcg/kg | 3 mg tablets, Rx |
| S. stercoralis, gut | Ivermectin ~200 mcg/kg | Beats albendazole 200 mg BID x 3 days on the ivermectin label |
| Pinworm | Mebendazole 100 mg once, or albendazole 400 mg, or pyrantel | Pyrantel is the US OTC; both benzimidazoles are Rx |
| Ascaris, hookworm, whipworm | Mebendazole 100 mg BID x 3 days, or programme albendazole 400 mg | EMVERM vs WHO single-dose habits |
| S. scabiei | Ivermectin 200 mcg/kg x 2 (guideline) or permethrin | Oral ivermectin off US label |
| T. solium cysts in brain, E. granulosus cysts | Albendazole cycles with food | Albenza US indications |
A stool species, a tape test, a skin scraping, or a travel plus serology comes first. Brand loyalty does not. Ivermectin is a macrocyclic lactone. Mebendazole and albendazole are benzimidazoles. They do not substitute across every parasite just because all three are 'dewormers.'
Ivermectin opens invertebrate glutamate-gated chloride channels. That is why it is strong against many nematodes and some arthropods and silent against the cysts albendazole is labeled for in the US.
Benzimidazoles bind worm beta-tubulin and starve glucose uptake. That is why mebendazole can sit in the gut and kill pinworm or Ascaris, and why albendazole's absorbed sulfoxide can reach hydatid and cysticercus tissue.
If no one has named the organism, the comparison table is not a menu. Vague bloating in a temperate city is often not a worm at all.
A single 'dewormer' search result will not tell you which of these three bottles matches a Latin name. CDC pages split pinworm, soil-transmitted helminths, Strongyloides, scabies, and filariae on purpose. Copy that split before you copy a milligram.
Albendazole stays prescription in the United States
Albenza and generic albendazole tablets are human prescription drugs. Mayo's consumer page says the medicine is available only with a doctor's prescription. DailyMed files list HUMAN PRESCRIPTION DRUG. This page will not call albendazole a US over-the-counter dewormer.
What is over the counter for pinworm in the US is pyrantel pamoate. CDC states that plainly. Mebendazole 100 mg is prescription. Ivermectin 3 mg is prescription. Confusing a Kenyan or Indian pharmacy shelf with a US aisle is the error.
The US albendazole label indications are narrow: parenchymal neurocysticercosis from Taenia solium larvae, and cystic hydatid disease of liver, lung, and peritoneum from Echinococcus granulosus. Common intestinal worms are CDC and WHO uses, not those two indication sentences.
Donation programmes still ship albendazole 400 mg for lymphatic filariasis and soil-transmitted helminths. That supply path is a ministry of health, not a grocery endcap.
Mayo's albendazole page also tells readers not to mix other medicines, including nonprescription ones, without asking the prescriber. That is the posture of a monitored drug, not a pinworm candy. If a US pharmacist will not hand it over without a script, the pharmacist is reading the category correctly.
People who met albendazole as a school swallow overseas often assume the same bottle sits next to pyrantel here. It does not. Ask for the legal name on the US bottle: Albenza or generic albendazole tablets, prescription, often 200 mg, two tablets when the order is 400 mg.
Mebendazole 100 mg versus albendazole 400 mg for gut worms
For pinworm, CDC lists three drugs: mebendazole 100 mg once, albendazole 400 mg once, or pyrantel 11 mg/kg once (max 1 g). Each is repeated in two weeks. Household treatment is the same idea for all three.
For a US 100 mg mebendazole pack, roundworm, hookworm, and whipworm are not single-tablet jobs. They are 100 mg morning and evening for three days. Albendazole in WHO school rounds is often one 400 mg swallow, or mebendazole 500 mg once, to cut burden in a classroom.
Those WHO single doses are preventive chemotherapy where baseline prevalence is at least 20% among children, yearly or twice yearly if prevalence is over 50%. They are not a claim that 400 mg albendazole is sold next to toothpaste in a US drugstore.
Head-to-head, albendazole's single 400 mg is easier to supervise. Mebendazole's three-day 100 mg course is the labeled US chewable rhythm for the heavier gut nematodes. Convenience is not the same as 'stronger.'
If the only bottle in the house is leftover albendazole from a trip, a clinician can still map pinworm onto 400 mg plus a two-week repeat. Mapping a tissue-cycle Albenza leftover onto a child's pinworm without looking at the indication is how people under- or over-treat.
Tissue cysts pick albendazole, not the other two
| Clock | Ivermectin 3 mg | Mebendazole 100 mg | Albendazole (US label) |
|---|---|---|---|
| How you count | mcg/kg tables | Fixed 100 mg | 400 mg BID if ≥60 kg; 15 mg/kg/day if lighter |
| With food? | Empty stomach on label; food for CDC scabies | Optional for lumen effect | Yes, with meals |
| Pinworm | Not the US pick | 1 tablet; 2-3 week logic | CDC 400 mg once, repeat 2 weeks (off US label text) |
| Strongyloides | 200 mcg/kg once | Not preferred | Label comparator, inferior on stools |
| Oncho / scabies | Yes / guideline | No | No |
| Brain or hydatid cysts | No | No reliable US role | Labeled cycles + labs |
For hydatid disease in a person 60 kg or more, Albenza is 400 mg twice daily with meals for a 28-day cycle, then 14 days off, for three cycles. Under 60 kg the daily amount is 15 mg/kg in two doses, capped at 800 mg per day.
For neurocysticercosis the same daily milligrams run for 8 to 30 days, with food. Steroids and anticonvulsants are part of that plan because dying cysts in brain can swell and seize. Eyes get examined for retinal cysts before the first dose.
Blood counts start each 28-day cycle and every 2 weeks on therapy. Liver enzymes follow the same calendar. Bone-marrow suppression is a labeled, sometimes fatal, risk. Mebendazole 100 mg BID for three days does not replace that monitoring, because mebendazole barely circulates.
Ivermectin has no role on those two Albenza rows. A 150 mcg/kg oncho count does not enter a hydatid cyst. Do not 'add ivermectin for coverage.'
Albendazole sulfoxide, the active metabolite, reaches peak around 2 to 5 hours after a 400 mg dose with a fatty meal in hydatid patients. Half-life of that metabolite is about 8 to 12 hours. Food is mandatory on this file. It is optional chatter on EMVERM.
Ivermectin or a benzimidazole: the first fork
Take ivermectin when the job is river blindness, intestinal Strongyloides, guideline scabies, or a filariasis pair that WHO already wrote. The US tablet is 3 mg, counted. Empty stomach for the labeled worms. Food if a clinician is using the CDC scabies line.
Take a benzimidazole when the job is pinworm or the common soil-transmitted gut trio on the EMVERM list. Ivermectin is the wrong first reflex there in a US clinic.
The STROMECTOL clinical section already compared ivermectin with albendazole 200 mg twice daily for 3 days in Strongyloides and found ivermectin better on stool cure. That is a species-specific win. It is not proof ivermectin wins whipworm.
Whipworm is a benzimidazole problem. Ivermectin's reputation from oncho programmes does not transfer. People who 'just take Stromectol for worms' after a tropical holiday skip the species step.
Loa loa risk in Central and West Africa can make ivermectin the dangerous choice even when oncho is the intended target. A benzimidazole does not erase that geography. It also does not treat oncho microfilariae the way 150 mcg/kg does.
Weight-count versus fixed chewable versus meal-tied 200 mg
Ivermectin asks for a scale or a height pole and a 3 mg strip. Miss the infection and you pick the wrong table (150 versus 200 mcg/kg). Miss the stomach rule and you ignore the labeled PK note.
Mebendazole 100 mg asks for a calendar: one box on one morning, or two boxes a day for three days. Weight drops out. Age under two does not.
Albendazole 200 mg tablets are often doubled to make 400 mg. Tissue disease then locks you to meals, cycles, and lab draws. A traveler's leftover 400 mg 'dewormer' is not that regimen.
Filariasis pairing can put ivermectin and albendazole in the same cup. That is a programme design against microfilariae plus intestinal worms. It is not a reason to combine all three drugs for pinworm in Ohio.
DEC belongs in that pairing talk only when onchocerciasis is absent. WHO keeps DEC out of oncho-endemic units because of severe reactions. Adding DEC at home because a comparison chart showed three letters is malpractice-grade improvisation.
Height poles in mass ivermectin rounds exist so a worker can approximate the 3 mg count without a scale. They do not convert mebendazole 100 mg into a weight-based drug. They do not convert Albenza into an OTC chew.
The wrong tablet is usually a guessed worm
Match ivermectin to the infections on its US file and to the guideline mite and WHO pair uses. Match mebendazole 100 mg to pinworm and the three-day nematodes. Match albendazole to US tissue indications and to CDC or WHO gut uses, as a prescription, not as a pretend OTC.
COVID stories that borrow the 150 mcg/kg oncho count are a separate failure, written on the claims page. How to chew 100 mg is a separate walk on the mebendazole insight.
If the organism is still a guess, stop shopping tablets. Get the test. Then pick the row.
A traveler with eosinophilia and tropical soil exposure may need Strongyloides serology, not another 100 mg chewable. A child with night anal itch needs tape, then pinworm math. A seizure work-up with cystic lesions needs Albenza plus steroids, not 150 mcg/kg. Those three people should not share a leftover bottle.
If two of the three bottles could work, pick the one you can legally obtain and complete. A finished pyrantel pinworm course beats an unfinished imported albendazole guess. A counted 3 mg ivermectin swallow for documented Strongyloides beats a three-day mebendazole course aimed at the wrong species.