The human tablet is 3 mg; the dose is micrograms per kilogram

Weigh the person before anyone counts 3 mg

Start with mass, not with a product story. The 3 mg tablet is a counting chip. You do not invent a strength. You stack chips until the labeled mcg/kg is on the table.

FDA-style rows for the human 3 mg tablet. Bands overlap on purpose because the two indications use different mcg/kg targets. A clinician still owns the indication. This desk does not ship chips.

Kilograms decide the tablet count before anyone talks about brand stamps or grocery coupons. Convert pounds by dividing by 2.2. A 154 lb adult is 70 kg. If you drop pounds into a mcg/kg equation you underdose by more than half and leave Strongyloides in the gut. Stand on a scale. Winter-coat guesses are how charts fail.

The US oral tablet is 3 mg. There is no 6 mg or 12 mg human pill on the American label. Tablet count times three is the milligram total. Compare that total to body weight times 150 or 200 mcg/kg, depending on the indication. Reviews that say 'take two and go to bed' are writing a child's row for an adult worm.

A 70 kg person at 200 mcg/kg needs 14 mg. Five 3 mg tablets is 15 mg. That is the official rounding, not a math error you should 'fix' with a livestock syringe. At 80 kg and above the strongyloides chart sends you back to raw mcg/kg instead of a fixed row. Heavier adults are not a vibe. They are a calculator.

Current weight owns the row. Edema, pregnancy, and a large gain or loss since last year's license move the number. Children use the same chips once they sit on a labeled row. Historical caution under 15 kg is about missing rows, not a secret extra-strength drop hiding in a barn aisle.

Off-label scabies often copies the 200 mcg/kg idea, then repeats the count one to two weeks later because eggs hatch after the first kill. Crusted scabies can need several rounds plus a topical under specialist care. Those extra counts are still 3 mg human tablets stacked against kilograms. They are not a reason to open a tube meant for a 500 kg animal.

Livestock paste is built for a different animal

Horse and cattle tubes list a concentration meant for bodies that may weigh hundreds of kilograms. The paste is not a 3 mg tablet. People who eyeball a strip have shown up with vomiting, ataxia, visual change, and seizures. That is overdose. It is not a bold biohack and it is not a Mazzotti itch.

Cheap listings that skip a prescription often sell the same paste, or unregulated bars stamped 6 mg and 12 mg as if those were US human strengths. They are not. Generic Stromectol from a licensed US pharmacy is the same molecule as brand when it is a real 3 mg tablet. The savings, if any, live in coupon and grocery bands below - not in a feed-store aisle.

Topical ivermectin for rosacea (Soolantra) and a lice lotion (Sklice) are different products with different directions. This page is the oral 3 mg tablet. A face cream is not a kg chart. Mixing those labels is how a reader swallows a veterinary gel 'because the tube said ivermectin.'

If a comment thread promises overnight paste for a virus, close it. Large outpatient COVID trials did not show a clinical benefit at doses a person can actually take. Dish assays that looked promising used concentrations that would be toxic in a human. Paste on top of that story is how an emergency bay gets a confused, seizing patient who thought they were being clever.

Four grocery counters, qualitative bands only

Human 3 mg tablets only. Bands from public US coupon and grocery-pharmacy checkers in August 2026. No dollar cells. Prescription required. ZIP and quantity move the band. Livestock paste is not a row. PharmaFactBase has no cart.

Licensed grocery pharmacies already publish coupon and warehouse checkers for human 3 mg tablets. Common outpatient counts are four or six pills - enough for a mid-weight adult on one labeled pass, or a short scabies pair when the prescriber writes it that way. Cash without a coupon often sits in a mid-to-high retail band. A published coupon or a house grocery price usually drops the same count into a low band.

The four counters on this page are Meijer, Safeway, Rite Aid, and H-E-B. They are real US pharmacies. ZIP code moves the band. So does the day's contract. That is why the table prints qualitative bands and refuses a dollar cell. A number I invent is wrong by next Tuesday and wrong two ZIP codes over.

A site that ships tablets after a checkbox and a card number is not a clinic. If the band looks 'too cheap' and the seller is a warehouse in another country, that is not a bargain. That is a different product. Prescription, human 3 mg, kilogram chart. Those three conditions are the whole cheap-versus-safe argument.

Strongyloides wants 200; river blindness wants 150

Intestinal Strongyloides and river blindness do not share a mcg/kg target. Mix them and you either under-treat a gut worm or overshoot a program dose without a reason. The US oral label covers strongyloidiasis due to Strongyloides stercoralis and onchocerciasis due to Onchocerca volvulus. Scabies, head lice, and some other nematodes sit off that tablet label. A clinician still owns those calls.

Strongyloides can autoinfect. A single labeled count often works, but stool follow-up exists because a missed larva becomes next month's worm. Immunosuppression - including a later prednisone burst - can turn a quiet gut infection into hyperinfection. That is why endemic-soil history belongs on the steroid chart, not in a kitchen experiment the night before a burst. See steroids and tapering for the clock. Different page, same desk.

Onchocerca adult worms live on. Ivermectin kills circulating microfilariae and reduces female fecundity for months. River-blindness programs therefore repeat every 6 to 12 months instead of claiming a one-time cure. That interval is about adult survival, not about a weak 3 mg chip.

Mass-drug-administration programs in Africa and Latin America have given hundreds of millions of weight-based human doses. That supervised 150-200 mcg/kg file is the safety record that matters. Pantry experiments with paste are not in that file. Satoshi Omura and William Campbell shared the 2015 Nobel Prize for the parasite work. The prize is about worms. It is not a viral trophy.

Glutamate channels stay open until the worm stills

Invertebrate nerve muscle carries glutamate-gated chloride channels that human neurons do not pack at the same sites. Ivermectin holds those channels open. Chloride floods in. The parasite paralyzes and starves. That is the selectivity, not magic. It is also why a virus does not care about this tablet. Viruses do not use those channels.

P-glycoprotein at the blood-brain barrier pumps ivermectin back out of a healthy human brain. A labeled worm dose barely registers centrally in most people. Drugs or rare genetics that weaken that pump can, in theory, let more drug through. That is a medication-review item, not a reason to double the tablets.

Scabies mites are arthropods with the same channel family. Two weight-based counts a week or two apart cover the hatch. Itch that lingers after the mites are dead is immune leftover, not proof the 3 mg math failed. New burrows are the failure sign. New tracks on the hands or belt line. A contact who was never treated.

People mix this drug up with ciprofloxacin because both show up in 'strong pill' threads. They are not cousins. One opens worm chloride channels. The other poisons bacterial DNA gyrase and carries tendon boxed warnings. If the problem is a bacterium, this tablet is the wrong page.

Central Africa is a screening question, not a rumor

High Loa loa microfilarial loads in Central and West African endemic zones can turn a standard ivermectin dose into encephalopathy when the load dies at once. That event is documented and sometimes fatal. It is not a forum scare invented in 2021. Programs that give ivermectin for onchocerciasis or filariasis screen or avoid treatment when the Loa loa load is high. Individual clinicians should do the same before a high-stakes dose.

A weekend in Paris is not the risk set. Long residence or travel in the endemic belt is. Without that exposure, a labeled 150-200 mcg/kg count has an excellent safety record across mass campaigns. Do not skip a needed Strongyloides treatment because a thread said 'brain swelling.' Do not skip the travel history because another thread said 'it is always safe.' Both halves of that sentence are the job.

Confusion, severe lethargy, or a drop in consciousness after a dose is urgent - whether or not you think you have Loa loa. Expected itch and low-grade ache after a program dose are not that picture. Bring the geography to clinic in the first sentence. 'I lived in Cameroon' is more useful than 'I read a scary post.'

Labeled worms used water; some mite plans use breakfast

Stromectol studies for labeled worms used an empty stomach with water. That remains the default I write for strongyloidiasis and onchocerciasis. Peak plasma sits near four hours. Half-life is about 18 hours, with metabolites that hang around longer. A single count can cover parasites present today while leftover drug trails into the next day. That trail is not a license to redose because you feel itchy tonight.

A high-fat meal can raise bioavailability about two-and-a-half-fold. Some scabies protocols want that extra skin exposure and say take with food. Do not mix the two ideas on the same night because a review said 'always with peanut butter.' Match the indication. Water either way. No alcohol experiment. No paste chaser.

Metabolism is hepatic, mainly CYP3A4. Distribution is lipophilic - fat and skin see the drug. Elimination is almost entirely fecal over roughly twelve days. Urine carries very little. Kidney failure rarely needs a dose rewrite, unlike a renally cleared antibiotic such as ciprofloxacin. Grapefruit and some azoles can raise levels. Warfarin effect can tick up. Check INR if the patient lives on a thin therapeutic window.

Protein binding is high. Drug-drug fights at CYP3A4 or P-glycoprotein matter more when someone is on repeat counts - crusted scabies, program retreatment - than after one supervised tablet. Repeat counts are still 3 mg chips against kilograms. They are not a reason to invent a new strength.

A second 3 mg count waits for eggs that hatch late

Scabies eggs hatch after the first kill, which is why a single heroic Saturday night does not finish a household. Classic regimens pair a weight-based oral count with a topical and then repeat the oral count at one to two weeks. Treat everyone the same morning. Wash or bag the bedding. If you only treated yourself and your partner still itches, you did not fail the drug. You failed the house.

Post-scabetic itch commonly lasts two to four weeks after mites are dead. The immune system keeps shouting. That itch is miserable and it is not a culture of live mites. Antihistamines, moisturizer, and time are the usual tools. A third ivermectin count is not a lotion. Live failure looks like new burrows, new tracks, or a skipped contact.

Crusted scabies is a different disease - thick scale, huge mite counts, often in frail or immunosuppressed people. That needs several weight-based counts plus a topical, often under specialist care. One 3 mg evening does not finish it. Bring the timeline to clinic: date of first count, date of second, who was skipped. That list is more useful than another internet review.

Head lice have their own topical products. Swallowing leftover 3 mg tablets because a school note said 'bugs' is not a lice protocol. Ask what species is on the person. Mites, lice, and gut worms are not interchangeable just because a tube in a barn says ivermectin on the label.

Large COVID studies closed the leftover-antiviral story

Outpatient platform trials on COVID closed the leftover-antiviral story at doses people can actually swallow. TOGETHER, ACTIV-6, and the major randomized studies did not find a meaningful clinical benefit. Lab dishes that looked 'promising' needed concentrations you cannot take safely. Using a worm drug for a virus wastes days and, with paste, can land you in a bay.

Leftover 3 mg tablets from a prior worm or mite treatment are not a cold kit. Your leftover four tablets may be a child's row or half an adult row, depending on who they were written for. Self-dosing also blows the kg chart. If the leftover came from a barn, that is an emergency-department story waiting to happen, not a weekend plan.

No supplement stack turns this into an antiviral. Zinc, vitamin D, and 'immune' powders do not rewrite those trials. If the other drug in the drawer is a fluoroquinolone or a steroid, you are usually treating a different problem - see ciprofloxacin and steroids and tapering rather than stacking pages. Dr. Marta Reyes answers the leftover questions below.

If you still have unused human 3 mg tablets, ask the original prescriber whether they should be kept for a documented parasite plan or returned. Do not invent a new indication on a Saturday. Viruses do not read this chart.

Program itch is not the same as paste poisoning

Dying microfilariae can itch and ache after a supervised onchocerciasis dose. That Mazzotti-pattern discomfort is expected in programs and is not the same as ataxia, visual snow, and seizures after a livestock strip. One is dying parasites. The other is a human brain seeing a veterinary concentration.

Expected: low-grade ache, itch, maybe a short fever after a labeled count in a person with a real parasite load. Urgent: confusion, severe vomiting, inability to walk a straight line, new visual loss after paste or after an unknown internet tablet. Say 'ivermectin' and 'paste or tablet' in the first sentence at triage. Do not make them guess from a vitamin story.

People who 'estimate a strip' have been admitted. That file grew during the years when COVID threads treated a barn aisle as a clinic. The molecule in the tube can be related. The concentration, the inactive ingredients, and the intended species are not. Related is not interchangeable.

Everyone in the house treats on the same calendar

Contacts who share bedding need the same morning, not a staggered weekend when someone 'feels less itchy.' Classic scabies is a household diagnosis dressed up as one person's rash. Skip a partner and you donate mites back to the person you just treated. Bag the unwashable stuffed animals. Wash the washable ones hot. This is unglamorous and it works.

Shelters, dorms, and nursing units need a coordinated plan, not one heroic 3 mg evening. Crusted cases shed heavily. Staff who only treat the index patient watch the unit bounce. Public-health and dermatology pairs exist for that reason. This page will not email a unit protocol.

Pregnancy in a scabies shelter is not a website yes. Oral ivermectin data in pregnancy are limited; first trimester gets the most caution. Permethrin topical is often the first conversation for classic scabies in pregnancy. Oral ivermectin enters the talk when the mite burden or the setting makes topical fail. Bring gestational age and whether anyone is crusted. Come in. Do not crowd-source a teratogen-adjacent decision from a thread that also sells paste.

Tell the steroid writer about endemic soil and eosinophils

Occult Strongyloides plus a high-dose steroid is how hyperinfection starts. Do not self-dose leftovers the night before a prednisone burst. Do tell the person writing the steroid if you have walked barefoot in endemic soil, had unexplained eosinophilia, or came from a Strongyloides region. Screening and a supervised kg count, when indicated, happen before the steroid.

Hyperinfection is not a mild repeat of ordinary gut strongyloidiasis. Larvae move. Gram-negative bacteremia can ride along. Mortality is real. The prevention is a travel and eosinophil question, not a leftover 3 mg Saturday. See steroids and tapering for the burst-and-taper clock.

If someone already started high-dose steroid and then the eosinophil story appears, that is a same-week call, not a wait-and-see. Name both drugs. Name the soil history. Marta Reyes will not write a kitchen protocol in email. She will tell you to bring the pair to clinic.

Bring the kilograms and the parasite name to clinic

Marta signs this page as education, not as a refill. Weigh. Name the parasite or the mite. Count 3 mg human tablets against the labeled mcg/kg. Leave the barn tube on the shelf. If the arithmetic still feels like a forum fight, bring the scale printout and the travel history to a licensed prescriber and a human pharmacy.

Questions that belong on this desk are kilogram rows, paste mix-ups, hatch windows, and Loa loa geography. Questions that do not belong are vendor lists, overnight paste, and viral leftovers. The disclaimer is the legal version of that split. Your own clinician writes the order.

Reader consultation

Your questions, answered by Dr. Marta Reyes, MD

Family medicine, dermatology & infectious disease

Marta Reyes answers weight-chart questions on the human 3 mg tablet. Clinic tone. No cart.

Priya: Do I take the 3 mg tablets with food or on an empty stomach?

For labeled worms I write empty stomach with water, because that is how Stromectol was studied. A fatty meal can raise blood levels about two-and-a-half times. Some scabies protocols want that extra skin exposure and say take with food. Match the indication. Do not mix the two ideas because a review said always with peanut butter. Water either way.

Tomas: My bathroom scale only shows pounds. How do I use the kg chart?

Divide pounds by 2.2. A 154 lb adult is 70 kg. Then use the FDA row or the 200 mcg/kg math. Do not drop pounds into the mcg/kg equation or you will underdose by more than half. I would rather you stand on a clinic scale than invent 180 lb from a winter coat. Bring the number.

Nadia: Is a US generic 3 mg tablet as good as Stromectol?

A US-regulated generic 3 mg tablet has to meet the same strength and quality bars. The kg chart does not change. What changes is the cash band at the counter - grocery and coupon fills often sit lower than brand. What never matches brand is a paste tube or an unregulated 12 mg bar from a site that does not ask for a prescription. I stamp generic human tablets. I do not stamp barn aisles.

Owen: I am pregnant and the shelter has scabies. Now what?

This is not a website yes. Pregnancy data for oral ivermectin are limited; first trimester gets the most caution. Permethrin topical is often the first conversation for classic scabies in pregnancy. Oral ivermectin enters the talk when the mite burden or the setting makes topical fail. Bring gestational age, the household plan, and whether anyone is crusted. Come in or call the obstetric and ID pair who can see you.

Keiko: Should I swallow leftover ivermectin the night before a steroid burst?

Do not self-dose leftovers. Do tell the person writing prednisone if you have walked barefoot in endemic soil, had unexplained eosinophilia, or came from a Strongyloides region. Occult worm plus high-dose steroid is how hyperinfection starts. Screening and a supervised kg count, when indicated, happen before the steroid. See steroids and tapering for that clock.

Rafael: Why does this page refuse to type a dollar for 3 mg x 4?

Because a dollar I invent is wrong by next week and wrong two ZIP codes over. The fill table uses bands - coupon-low, chain-mid, retail-high - from public US checkers in August 2026. A licensed counter quotes the number that exists that day. This desk publishes the chart, not a price list.

General education from a clinician, not personal medical advice. Bring your own history to your own prescriber.