Ivermectin is dosed by body weight, not by a fixed number of tablets. Every approved regimen is expressed in micrograms per kilogram (mcg/kg), and the correct dose for a 55 kg adult is materially different from the correct dose for a 110 kg adult. This page sets out the arithmetic and gives conversion tables for the three regimens that appear most often in the prescribing literature.
The calculation is straightforward: dose in micrograms = body weight in kilograms × the mcg/kg figure. Divide by 1,000 to convert to milligrams. A 70 kg person on a 200 mcg/kg regimen therefore needs 70 × 200 = 14,000 mcg, which is 14 mg.
To convert pounds to kilograms, divide by 2.205. A 180 lb person weighs about 81.6 kg. On the same 200 mcg/kg regimen that is roughly 16.3 mg.
Tablets come in fixed strengths, so the practical dose is rounded to the nearest achievable tablet combination — conventionally rounded up rather than down, because ivermectin has a wide therapeutic margin and underdosing is the more common cause of treatment failure.
This is the dose used for river blindness (onchocerciasis) and in the mass drug administration programmes that have suppressed the disease across much of West Africa. It is given as a single dose, repeated at 6 or 12 month intervals.
| Body weight | Weight (lb) | Dose at 150 mcg/kg | 12mg tablets |
|---|---|---|---|
| 15–25 kg | 33–55 lb | 3 mg | ¼ tablet |
| 26–44 kg | 57–97 lb | 6 mg | ½ tablet |
| 45–64 kg | 99–141 lb | 9 mg | ¾ tablet |
| 65–84 kg | 143–185 lb | 12 mg | 1 tablet |
| 85–110 kg | 187–242 lb | 15–18 mg | 1½ tablets |
This is the most widely used strength. It is the FDA-labelled single dose for intestinal strongyloidiasis and the standard per-dose figure for scabies, where it is repeated after 7 to 14 days because ivermectin does not kill mite eggs.
| Body weight | Weight (lb) | Dose at 200 mcg/kg | 3mg tablets | 12mg tablets |
|---|---|---|---|---|
| 15 kg | 33 lb | 3 mg | 1 | ¼ |
| 30 kg | 66 lb | 6 mg | 2 | ½ |
| 45 kg | 99 lb | 9 mg | 3 | ¾ |
| 60 kg | 132 lb | 12 mg | 4 | 1 |
| 70 kg | 154 lb | 14 mg | 5 | 1¼ |
| 80 kg | 176 lb | 16 mg | 5–6 | 1½ |
| 90 kg | 198 lb | 18 mg | 6 | 1½ |
| 100 kg | 220 lb | 20 mg | 7 | 1¾ |
| 110 kg | 242 lb | 22 mg | 7–8 | 2 |
| 120 kg | 265 lb | 24 mg | 8 | 2 |
Doses around 400 mcg/kg appear in lymphatic filariasis programmes, in some crusted scabies protocols, and in the higher-dose arms of clinical pharmacology studies. Escalation studies published in the Journal of Clinical Pharmacology administered doses up to 2,000 mcg/kg to healthy volunteers without a dose-limiting toxicity emerging, which is the basis for the frequently repeated statement that ivermectin has a wide safety margin.
That safety margin is not an invitation to self-escalate. The pharmacokinetic studies were conducted under medical supervision with monitoring, in people screened for the conditions that raise risk. Higher doses increase both peak plasma concentration and the chance of the neurological adverse effects described on our side effects page.
Ivermectin is lipophilic and poorly soluble in water. Taking it with a high-fat meal raises systemic exposure substantially — the manufacturer's own pharmacokinetic data showed roughly a 2.5-fold increase in bioavailability compared with the fasted state.
This matters because the FDA label directs that ivermectin be taken on an empty stomach with water, while much of the clinical literature and many prescribers now advise taking it with food precisely to achieve higher exposure. The two are not contradictory: the label reflects the conditions under which the registration trials were run. Which approach applies to you is a question for your prescriber. See ivermectin with or without food.
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 pricingMultiply your weight in kilograms by the mcg/kg figure for your regimen, then divide by 1,000. At the common 200 mcg/kg strength, a 70 kg (154 lb) adult needs 14 mg and a 90 kg (198 lb) adult needs 18 mg. Round to the nearest achievable tablet combination and confirm with your prescriber.
At 200 mcg/kg, one 12mg tablet covers roughly a 60 kg person. Most adults between 60 and 120 kg fall between one and two 12mg tablets per dose. Below 60 kg, tablets are commonly split or a 3mg strength is used instead.
Divide pounds by 2.205. 150 lb is 68 kg, 180 lb is 81.6 kg, 200 lb is 90.7 kg, 250 lb is 113.4 kg. All published ivermectin dosing is expressed per kilogram, so this conversion is the first step in any calculation.
The per-dose strength is the same 200 mcg/kg, but the schedule differs. Intestinal strongyloidiasis is treated with a single dose. Scabies requires two doses 7 to 14 days apart because the drug does not kill mite eggs, so a second dose is needed to kill mites that hatch after the first.
Ivermectin has a wide margin between the therapeutic dose and the dose at which harm occurs; supervised studies have used many times the standard dose without dose-limiting toxicity. A modest rounding error is unlikely to cause a problem. Substantial overdose can cause dizziness, vision disturbance, vomiting and in extreme cases neurological effects, and should prompt a call to a poison control centre.