Ivermectin is a prescription-only oral medication, and there is no single “standard” dose — the correct amount depends on body weight, the condition being treated, and a clinician’s assessment. This guide lays out the FDA-approved weight-based dosing tables and the CDC’s scabies dosing guidance, explains how those numbers are calculated, and shows how tablet counts change depending on strength (3 mg vs. 6 mg). It is intended to help you understand a prescription you’ve already been given, or a conversation you’re about to have with your doctor or pharmacist — not to replace either.
Key Takeaways
- Ivermectin dosing is calculated in micrograms per kilogram of body weight (mcg/kg), not as a flat adult dose.
- Strongyloidiasis: single dose at 200 mcg/kg.
- Onchocerciasis: single dose at 150 mcg/kg.
- Scabies (CDC guidance): 200 mcg/kg, given as two doses 7–14 days apart, taken with food.
- A typical 60 kg (132 lb) adult receiving the strongyloidiasis dose takes about 12 mg total — commonly four 3 mg tablets.
- Ivermectin is not FDA-approved for COVID-19 prevention or treatment.
- Every dose in this article should be confirmed against your own prescription — dosing bands are based on the FDA drug label, but your prescriber may adjust for other factors.
What Determines an Ivermectin Dose?
Ivermectin dosing isn’t a fixed number of milligrams the way some medications are (like a “500 mg” antibiotic). Instead, the FDA-approved prescribing information sets the dose as a target concentration per kilogram of body weight, because plasma drug levels scale with body size and the drug has a narrow margin between an effective dose and one that risks side effects.
Three things determine the exact dose a clinician prescribes:
- Indication. Strongyloidiasis, onchocerciasis, and scabies each have different mcg/kg targets and dosing schedules.
- Body weight. Heavier patients need more total ivermectin to reach the same mcg/kg target; lighter patients need less. The FDA label has not established safety or efficacy in patients under 15 kg (about 33 lb).
- Tablet strength available. The same mcg/kg target translates into a different number of tablets depending on whether you’re prescribed 3 mg or 6 mg tablets.
Ivermectin tablets are typically taken as a single oral dose on an empty stomach with a full glass of water. Scabies treatment is the exception: CDC guidance notes that taking ivermectin with food increases absorption and is preferred for that indication, even though it runs counter to the general labeling instruction.
Because ivermectin is available only by prescription in the U.S., these figures are meant to help you understand a dose your clinician has already selected — not to calculate your own dose without medical supervision.
Ivermectin Dosage Chart by Weight (kg)
The tables below reproduce the FDA drug label’s official weight-banded dosing guidelines for 3 mg tablets, plus CDC’s scabies protocol. Dosing bands round up to the nearest whole tablet to make sure the minimum effective mcg/kg target is met — so the mg amount you actually take may run slightly above the raw mcg/kg × weight calculation. That’s expected and is how the FDA table is designed to work.
Strongyloidiasis Dosage Chart (200 mcg/kg, single dose)
| Body weight | Single oral dose (3 mg tablets) |
|---|---|
| 15–24 kg (33–53 lb) | 1 tablet |
| 25–35 kg (55–77 lb) | 2 tablets |
| 36–50 kg (79–110 lb) | 3 tablets |
| 51–65 kg (112–143 lb) | 4 tablets |
| 66–79 kg (146–174 lb) | 5 tablets |
| ≥80 kg (≥176 lb) | Dosed individually at 200 mcg/kg |
Follow-up stool exams are typically needed 3–4 weeks after treatment to confirm the infection has cleared, since a single dose doesn’t always eliminate it on the first try.
Onchocerciasis Dosage Chart (150 mcg/kg, single dose)
| Body weight | Single oral dose (3 mg tablets) |
|---|---|
| 15–25 kg (33–55 lb) | 1 tablet |
| 26–44 kg (57–97 lb) | 2 tablets |
| 45–64 kg (99–141 lb) | 3 tablets |
| 65–84 kg (143–185 lb) | 4 tablets |
| ≥85 kg (≥187 lb) | Dosed individually at 150 mcg/kg |
Ivermectin doesn’t kill adult Onchocerca volvulus parasites, only the microfilariae — so retreatment every 3–12 months is often part of the treatment plan, not a sign the first dose failed.
Scabies Dosage Chart (200 mcg/kg, per CDC — off-label use)
Ivermectin is not FDA-labeled for scabies, but it’s a CDC-recommended standard of care:
- Classic (uncomplicated) scabies: two oral doses of 200 mcg/kg, spaced 7–14 days apart, taken with food.
- Crusted scabies: used alongside a topical scabicide, with more intensive regimens — 3, 5, or 7 doses depending on severity, on a schedule set by a specialist (e.g., days 1, 2, 8, 9, 15, 22, 29 for the most severe cases).
Use the strongyloidiasis table above as the per-dose tablet reference, since both use the same 200 mcg/kg target — the difference for scabies is that it’s given as two (or more) doses rather than one.
Ivermectin Dosage for Adults (mg)
There’s no universal “adult dose” in milligrams because the correct amount scales with weight. The table below shows approximate total milligrams for common adult body weights across the three main indications, based on the mcg/kg targets above.
| Adult weight | Strongyloidiasis (200 mcg/kg) | Onchocerciasis (150 mcg/kg) | Scabies, per dose (200 mcg/kg) |
|---|---|---|---|
| 50 kg (110 lb) | 10 mg | 7.5 mg | 10 mg |
| 60 kg (132 lb) | 12 mg | 9 mg | 12 mg |
| 70 kg (154 lb) | 14 mg | 10.5 mg | 14 mg |
| 80 kg (176 lb) | 16 mg | 12 mg | 16 mg |
| 90 kg (198 lb) | 18 mg | 13.5 mg | 18 mg |
These are the raw mg figures from the mcg/kg formula. In practice, your pharmacy will round to the nearest whole tablet using the official banded charts above — so your actual prescribed mg total may be a little higher than what’s shown here.
How Many Ivermectin Tablets Should You Take?
Tablet count depends entirely on which strength you’ve been prescribed. The FDA-approved dosing charts above are built around the 3 mg tablet, the most common strength. If you’ve been prescribed a different strength, the tablet count changes even though the underlying mcg/kg target doesn’t.
3 mg tablets: use the strongyloidiasis or onchocerciasis chart above directly — each row already tells you the tablet count.
If Prescribed 6 mg Tablets
A 6 mg tablet contains twice the ivermectin of a 3 mg tablet, so the tablet count is roughly half. For example:
- A dose requiring three 3 mg tablets (9 mg total) would need one and a half 6 mg tablets.
- A dose requiring four 3 mg tablets (12 mg total) would need two 6 mg tablets.
Never split, estimate, or “eyeball” a tablet fraction on your own. Ask your pharmacist to confirm the exact tablet count and whether splitting a 6 mg tablet is appropriate for your prescription — not all tablets are scored for accurate splitting.
How to Calculate an Ivermectin Dose
Understanding the formula behind the chart can help you sanity-check a prescription, though it isn’t a substitute for one. Clinicians use two steps:
- Total mg dose = (body weight in kg × mcg/kg target) ÷ 1,000
- Number of tablets = total mg dose ÷ tablet strength (mg)
Worked example 1 — strongyloidiasis, 70 kg adult: 70 kg × 200 mcg/kg = 14,000 mcg = 14 mg. Divided by 3 mg tablets, that’s 4.67 — but the official FDA chart rounds this weight band (66–79 kg) up to 5 tablets (15 mg) to make sure the full effective dose is delivered.
Worked example 2 — onchocerciasis, 70 kg adult: 70 kg × 150 mcg/kg = 10,500 mcg = 10.5 mg. The FDA chart’s 65–84 kg band calls for 4 tablets (12 mg), again rounding up rather than under-dosing.
This is why the official weight-band tables — not a raw calculator — are the authoritative source for tablet counts. A generic “multiply and divide” calculator can get you close, but it won’t reflect FDA-specific rounding conventions or indication-specific rules like scabies’ two-dose schedule or crusted scabies’ extended regimens. If you use or build an interactive dosing calculator, it should default to the official banded chart, not raw division, and should carry the same “confirm with your prescriber” disclaimer as the rest of this page.
Safety, Contraindications & When Dosage Changes
Ivermectin is generally well tolerated at labeled doses, but dosing decisions can change based on the following, all per the FDA prescribing information:
- Pregnancy: Safety hasn’t been established; ivermectin should not be used during pregnancy except when a clinician determines the benefit outweighs the risk.
- Children under 15 kg: Safety and effectiveness haven’t been established below this weight threshold.
- Drug interactions: Post-marketing reports describe increased INR (a blood-clotting measure) when ivermectin is combined with warfarin — tell your doctor about all medications you take.
- Overdose and neurotoxicity signs: Confusion, drowsiness, disorientation, seizures, or loss of consciousness have been reported at both recommended and excessive doses. These require immediate medical attention.
- Immunocompromised patients (including HIV): May need repeated treatment courses on a schedule set by a specialist, since a single dose may not fully clear the infection.
- Loa loa co-infection: Patients being treated for onchocerciasis who have significant exposure to Central or West Africa should be assessed for loiasis first — treating onchocerciasis in the presence of heavy Loa loa infection has rarely led to serious encephalopathy.
If you experience severe rash, difficulty breathing, fainting, or neurological symptoms after taking ivermectin, seek emergency care.
Frequently Asked Questions
There isn’t a single standard dose — it’s calculated per kilogram of body weight and depends on the condition being treated. The two FDA-approved targets are 200 mcg/kg (strongyloidiasis) and 150 mcg/kg (onchocerciasis); CDC recommends 200 mcg/kg for scabies, given as two doses.
It depends on weight and indication. For example, a 60 kg adult being treated for strongyloidiasis takes about 12 mg total (commonly four 3 mg tablets), while the same adult treated for onchocerciasis takes about 9 mg.
Multiply your weight in kg by the mcg/kg target (200 or 150, depending on indication), then divide by 1,000 to get total mg. Then divide by your tablet strength for a tablet count — but always confirm against the official FDA weight-band chart and your prescription, since the chart rounds up to protect efficacy.
It ranges from 1 tablet (15–24 kg) up to 5 tablets (66–79 kg) for strongyloidiasis, and similarly 1–4 tablets for onchocerciasis depending on weight band. See the full charts above.
The mcg/kg target is the same, but the tablet count is roughly half, since each 6 mg tablet contains double the ivermectin of a 3 mg tablet. Your pharmacist should confirm exact counts, especially if a tablet needs to be split.
Both use the same 200 mcg/kg target per dose. The difference is frequency: strongyloidiasis is typically a single dose, while scabies (per CDC) requires two doses 7–14 days apart, taken with food rather than on an empty stomach.
Ivermectin’s safety and effectiveness haven’t been established in children weighing less than 15 kg. For children above that threshold, dosing follows the same weight-based charts as adults, based on their body weight rather than age.
Ivermectin tablets are prescription-only in the U.S. Understanding the dosing math can help you follow a prescription you’ve been given, but doses should always be confirmed and prescribed by a licensed clinician, not self-determined.
Reported effects include confusion, drowsiness, dizziness, disorientation, and in serious cases, seizures or loss of consciousness. Accidental exposure to concentrated veterinary formulations has caused more severe reactions. Seek emergency medical care for any of these symptoms.
No. The FDA has not approved or authorized ivermectin for preventing or treating COVID-19 in humans, and available data don’t show it’s effective for that purpose. Taking large or non-prescribed doses of ivermectin — especially animal formulations — has caused serious harm. Talk to your doctor about FDA-authorized options for COVID-19.
