Quick Answer: What Is Iverjohn and How Is It Dosed?
Iverjohn is a branded ivermectin tablet manufactured by Johnlee Pharmaceuticals, available in 3 mg, 6 mg and 12 mg strengths — the full range needed to cover ivermectin's weight-based dosing system. There is no single "Iverjohn dose": the number and strength of tablets is calculated by a prescriber from your body weight and the specific condition being treated. This article focuses on exactly how that calculation works and how to take the tablets correctly, alongside Iverjohn's approved uses and safety information.
What Is Iverjohn?
Iverjohn is Johnlee Pharmaceuticals' brand name for its ivermectin tablets. Ivermectin, the active ingredient, is an antiparasitic medicine that works by disrupting the nervous system of susceptible parasites. Iverjohn's medically recognised uses follow ivermectin's approved indications, which differ by country — in the UK, intestinal strongyloidiasis, lymphatic filariasis, and human sarcoptic scabies; in Australia, onchocerciasis, intestinal strongyloidiasis, and scabies; in the USA, intestinal strongyloidiasis and onchocerciasis only, not scabies. It's prescription-only in all three.
Why Dosage Isn't a Single Number
This is worth being direct about, because it's the most commonly misunderstood part of ivermectin treatment. Dosing depends on several factors together:
- Body weight — the standard single dose across licensed indications is approximately 200 micrograms per kilogram, so the same diagnosis can mean a different tablet count for two different people
- Condition being treated — some conditions use a single dose, others a repeat course spaced days or months apart
- Country/product labelling — approved uses and exact dosing schedules differ between UK, Australian and US product information
- Individual factors — age, liver function, pregnancy status, and other medicines you take can all affect what a prescriber decides
We haven't built a dosage calculator here for the same reason no responsible medical resource should: the safest source for your exact dose is your prescriber, working from your actual current weight and the current product information — not a generic table applied to yourself.
What Do Strongyloidiasis, Filariasis and Scabies Actually Involve?
Briefly, since dosing only matters once you know what's being treated: strongyloidiasis is a roundworm infection that can persist for years thanks to an internal reinfection cycle unique to this parasite. Lymphatic filariasis is a mosquito-borne infection of the lymphatic system that can progress to chronic swelling if left untreated. Scabies is a skin mite infestation causing intense, often night-time itching. Onchocerciasis (river blindness), relevant in Australian and US labelling, is spread by blackflies and can cause serious skin and eye disease over time. See our dedicated guides on strongyloidiasis, lymphatic filariasis, and scabies for the full clinical detail behind each dosing schedule.
How Iverjohn's Three Strengths Map to Body Weight (UK Reference Table)
That said, understanding the general system helps make sense of why Iverjohn comes in three strengths. Per the current UK SmPC's reference table for the standard 200 mcg/kg single dose:
| Body Weight | Typical Tablet(s) |
|---|---|
| 15–24 kg | One 3 mg tablet |
| 25–35 kg | One 6 mg tablet (or two 3 mg) |
| 36–50 kg | Combination reaching approximately 9 mg |
| 51–65 kg | One 12 mg tablet |
| 66 kg and above | Combination of strengths, calculated individually |
This table is for understanding the general system only — it is not a substitute for your prescriber confirming your exact dose and tablet combination using your current weight. For lymphatic filariasis and scabies specifically, dosing schedules and repeat-dose timing differ from this single-dose strongyloidiasis pattern — see our lymphatic filariasis guide and UK scabies guide for those specifics.
How to Take Iverjohn Correctly
A few practical points matter beyond just "take as directed":
- Empty stomach — take with a full glass of water, generally around two hours before or after food. This isn't an arbitrary instruction: published research shows a high-fat meal can increase how much ivermectin the body absorbs by roughly 2.5 times, so the fasted-state instruction keeps your actual exposure aligned with your calculated dose
- Swallow whole — unless your prescriber has told you to crush the tablet (standard practice for children under 6)
- Take the full prescribed dose together as one dose, not split across the day
- Follow the repeat-dose schedule exactly if one applies to your treatment — for scabies, a second dose is often given 7–14 days after the first, since ivermectin doesn't reliably kill mite eggs
Our dedicated how-to-take guide covers timing, food, and missed-dose scenarios by treatment type in more depth than we can here.
What Is Iverjohn Used For?
Per current official product information:
| Country | Approved Uses |
|---|---|
| UK (MHRA/emc SmPC) | Intestinal strongyloidiasis; lymphatic filariasis; human sarcoptic scabies (typically second-line) |
| Australia (TGA) | Onchocerciasis; intestinal strongyloidiasis; scabies |
| USA (FDA) | Intestinal strongyloidiasis; onchocerciasis (not scabies) |
Side Effects of Iverjohn
Commonly reported: nausea, dizziness, headache, and mild diarrhoea. In people treated for filarial infections, a self-limiting reaction to dying parasites (fever, rash, joint pain) can occur. Rare but serious effects requiring urgent medical attention include severe skin reactions, signs of a severe allergic reaction, and confusion or seizures — see our full side effects guide.
Drug Interactions and Who Should Take Extra Care
No formal interaction studies exist for ivermectin; the clearest documented concern is with warfarin (raised INR reported). Extra caution applies for anyone under 15 kg, pregnant or breastfeeding, with significant liver impairment, or with a Loa loa-endemic travel history. Our drug interactions guide covers this fully.
What Happens If You Miss a Dose of Iverjohn?
Because dosing schedules genuinely differ by condition — a single dose for straightforward strongyloidiasis, a repeat dose for scabies, or scheduled 6- or 12-monthly dosing for lymphatic filariasis — there's no single missed-dose rule. Contact your prescriber or pharmacist for guidance specific to your course rather than assuming.
Iverjohn vs Generic Ivermectin
Iverjohn is a brand name; ivermectin is the active ingredient. Brand name alone doesn't establish superior effectiveness — your diagnosis, correctly calculated dose, and adherence to your prescriber's schedule are what determine outcomes.
If Your Doctor Has Prescribed Iverjohn
You can review the available strengths on the Medionix product pages for Iverjohn 3 mg, Iverjohn 6 mg, and Iverjohn 12 mg tablets, alongside our wider ivermectin range.
Storage Information
Store Iverjohn tablets in a cool, dry place, protected from light and moisture, in the original packaging, out of reach of children. Check the specific storage wording on your dispensed pack, and don't use tablets after the expiry date printed on it.
Sources & References
- electronic Medicines Compendium (emc) — Ivermectin 3mg Tablets, Summary of Product Characteristics
- Journal of Antimicrobial Chemotherapy — The effect of food on the pharmacokinetics of oral ivermectin
- Therapeutic Goods Administration (TGA), Australia — AusPAR: Stromectol (ivermectin)
Medical Disclaimer
This article is for general educational purposes and does not constitute individual medical advice. It is not a substitute for a consultation with a qualified doctor or pharmacist, who can confirm your exact dose. See our full Disclaimer Policy for more information.
