What it is used for
- River blindness (onchocerciasis)
- Strongyloidiasis (a threadworm-type infection)
- Some other parasitic worm infections
- Head lice and scabies (oral or topical forms in some settings)
- Topical form for inflammatory rosacea
How it works
Ivermectin paralyses and kills many parasites and parasitic worms by overstimulating their nerve and muscle signalling, which the parasite cannot survive. Human nerves are largely protected from this effect.
How it is taken
Taken as oral tablets, usually on an empty stomach with water, or applied as a cream or lotion for skin and lice conditions. Worm infections may need a single occasion or repeated courses. Take or apply it exactly as your doctor or pharmacist directs.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Dizziness
- Nausea
- Itching or mild rash
- Tiredness
- Muscle aches
- Mild swelling (often when many parasites are being cleared)
Serious effects — get help
- Signs of a severe allergic reaction such as facial swelling or breathing difficulty — seek emergency care
- Severe dizziness, fast heartbeat, or fainting — seek urgent care
- Confusion, severe drowsiness, balance problems, or seizures (especially relevant if certain other parasites are present) — seek urgent care
- Severe skin reaction — seek emergency care
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Strong sedatives and some medicines acting on the brain
- Blood thinners such as warfarin (monitoring may be needed)
- Other medicines that affect the same liver enzymes
Who should take care
- Tell your clinician if you have travelled to areas where a parasite called Loa loa is present, as treatment then needs special caution
- Report liver problems
- Inform your clinician if pregnant or breastfeeding
- Use only the human product prescribed for you — never use animal-formulated ivermectin
- Repeat courses are sometimes needed for certain infections