An antiparasitic treatment
Ivermectin
An antiparasitic taken by mouth for scabies, and used as a cream for rosacea.
What is Ivermectin?
Ivermectin is an antiparasitic medicine. Taken by mouth it is used for scabies, often when creams are hard to apply, when scabies is widespread or severe, or to treat outbreaks. As a skin cream it is used for the bumps and spots of rosacea. It works by paralysing and killing parasites such as scabies mites and the tiny mites linked to rosacea.
Education and reference only. This is a plain-language guide to Ivermectin — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Ivermectin is a medicine that kills various parasites. In the UK the oral form is used mainly for scabies — particularly severe or crusted scabies, widespread infestations and outbreaks, or when applying cream to the whole body is difficult. A separate cream form is used for the inflamed bumps and spots of rosacea. The oral and cream forms are used for different problems and are not interchangeable.
How it works
Ivermectin interferes with the nervous system and muscles of parasites, paralysing and killing them, while having little of this effect on humans at normal doses. For scabies this kills the mites burrowing in the skin. For rosacea, the cream is thought to work both by reducing the number of skin mites and by calming inflammation.
Company & origin
Originated / developed by: Merck (originator).
An antiparasitic medicine used in the UK for scabies and, as a cream, for rosacea.
Practical use
How to take Ivermectin
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take oral ivermectin exactly as prescribed, often as a single dose repeated after about a week for scabies.
- Treat close contacts at the same time for scabies, and keep up good hygiene with washing of bedding and clothes.
- For rosacea, apply a thin layer of the cream to the affected areas of the face once daily as directed, avoiding eyes, lips and inside the nose.
- Be patient: scabies itch can last for weeks afterwards, and rosacea improvement builds up gradually over weeks.
- If you miss a cream application, apply it when you remember unless it is nearly time for the next; for an oral dose, follow your prescriber's advice.
Weighing it up
Advantages & disadvantages of Ivermectin
Advantages
- Useful for scabies when whole-body creams are impractical or the infestation is severe.
- Helpful in managing outbreaks because a tablet is simple to give.
- The cream form offers an effective option for rosacea spots and bumps.
Disadvantages
- Oral and cream forms are different and must not be confused.
- Scabies usually needs a repeat dose and treatment of contacts.
- Rosacea cream needs regular use over weeks before the benefit is clear.
Practical use
Good to know
For scabies, oral ivermectin is often given as a dose that is repeated after about a week to catch newly hatched mites, and close contacts are treated at the same time as with cream treatment. As with permethrin, the itch from scabies can carry on for some weeks after the mites are dead, which does not mean the treatment has failed. The rosacea cream is used regularly over weeks to see the benefit, applied as a thin layer to the affected face. Always use the form your prescriber intended, as the oral medicine and the cream are very different products.
Who should not take it / use with caution
- Anyone who has had an allergic reaction to ivermectin should avoid it.
- Use in pregnancy, breastfeeding and in very young or low-weight children should be guided by a doctor.
- Tell your prescriber about other health problems, as some conditions need extra care.
Monitoring
- No routine blood tests are usually needed for short scabies treatment.
- Scabies is reviewed by whether the rash and burrows clear; itch may persist for weeks.
- Rosacea is judged by improvement in spots and redness over weeks of cream use.
Side effects
- Oral: sometimes itching, rash, dizziness, headache or tummy upset.
- Cream: skin burning, stinging, dryness or redness where applied.
- Rarely, more troublesome allergic-type reactions — seek advice if you feel unwell or the skin reacts strongly.
Key interactions
- Tell your prescriber about all your medicines, including those that thin the blood.
- Some medicines and supplements can change how oral ivermectin behaves, so check before combining.
- The cream has few interactions, but mention other facial treatments you use.
Available as: Tablets taken by mouth; a separate cream used for rosacea.
Answers
Ivermectin: frequently asked questions
When is the tablet used instead of cream for scabies?
Oral ivermectin is often chosen for severe or crusted scabies, widespread infestation, outbreaks, or when applying cream to the whole body is difficult.
Is the rosacea cream the same as the scabies tablet?
No. They are different products for different problems and are not interchangeable; use the form your prescriber intended.
Why might I need a second dose for scabies?
A repeat dose after about a week helps kill mites that hatch from eggs after the first treatment.
How long until the rosacea cream works?
It is used regularly and improvement usually builds up gradually over several weeks rather than straight away.
Will my itch stop straight away?
Not always; scabies itch can continue for some weeks after the mites are killed as the skin settles, which is normal.
The wider class
About Antiparasitic treatments
Ivermectin belongs to the antiparasitic treatments class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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