Moxidectin
Anthelmintics
Anthelmintics
Long-acting macrocyclic lactone related to ivermectin; a single oral dose clears Onchocerca microfilariae from the skin for months.
Quick facts
- Group
- Anthelmintics
- Target
- Nematode glutamate-gated chloride channel (GluCl)
- Used for
- Onchocerciasis
- Key effects
- Itching · Headache · Eosinophilia
- Monitor
- Itching · Blood pressure and dizziness on standing
No doses: the clinician sets them by the current guideline.
Mechanism of action
No structure with moxidectin is published; the figure shows ivermectin, a related macrocyclic lactone, in the GluCl channel of the nematode Caenorhabditis elegans.
Moxidectin belongs to the same family as ivermectin. In nematodes it is thought to act on glutamate-gated chloride channels (and possibly GABA receptors and ABC transporters), opening them so the worm's nerve and muscle cells are paralysed. It kills Onchocerca volvulus microfilariae and also stops adult females from releasing new ones for a time, but it does not kill the adult worms.
- Binds glutamate-gated chloride channels of the worm
- Chloride enters and nerve and muscle cells stop firing
- Microfilariae are paralysed and cleared from the skin
- Adult females release fewer microfilariae for months
Indications
- Onchocerciasis (river blindness) by Onchocerca volvulus in adults and children from four years Onchocerciasis (river blindness) →
- WHO lists it as a therapeutic equivalent of ivermectin for onchocerciasis and lymphatic filariasis Lymphatic filariasis →
Adverse effects
Common
- Itching, rash and skin swelling (Mazzotti-type reaction)
- Headache, fever, muscle and joint pain
- Eosinophilia, fast heart rate and low blood pressure
- Abdominal pain
Contraindications
- None absolute on the label; Loa loa is ruled out first in areas where it is common
Key interactions
- CYP3A4 substrates such as midazolam
- No relevant change: moxidectin does not affect CYP enzymes or P-glycoprotein.
- Food
- A fatty meal raises exposure a little; not clinically important.
What is monitored
- Itching, rash, fever and eye symptoms in the days after the dose
- Blood pressure and dizziness on standing
- Loa loa screening before treatment in endemic areas
Administration and safety
- Oral, single dose
- Repeat dosing has not been fully studied; follow-up is planned because adult worms survive
Pregnancy and breastfeeding
Human data are insufficient; rats showed fetal effects only at doses toxic to the mother. A clinician weighs the benefit.
Nursing care
- Ask about residence in areas where Loa loa is common
- Teach the patient to lie down if dizzy or faint, and to rise slowly
- Warn that itching and rash may appear as microfilariae die
- Breastfeeding is paused during treatment and for one week after the dose
Pharmacokinetics
- Absorption
- Oral; a high-fat meal raises exposure somewhat, but it can be taken with or without food.
- Metabolism
- Minimal metabolism in the liver; it is not a CYP3A4 substrate or inhibitor.
- Half-life
- Very long: about 23 days in people with onchocerciasis.
Test yourself
Think of the answer, then tap the question to see it.
Which disease is moxidectin approved for?
Onchocerciasis (river blindness) caused by Onchocerca volvulus.
Does moxidectin kill adult Onchocerca worms?
No. It kills microfilariae and temporarily stops adult females from releasing them, so follow-up is needed.
Why is Loa loa ruled out before moxidectin in endemic areas?
In co-infected people, killing Loa loa microfilariae can cause serious or fatal encephalopathy.
Which blood-pressure effect should patients be warned about after moxidectin?
Symptomatic orthostatic hypotension: dizziness or fainting on standing; they should lie down if it happens.
Connections
← Back to the class: Anthelmintics
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - MOXIDECTIN tablet (DailyMed (U.S. National Library of Medicine), 2026); Onchocerciasis (World Health Organization (WHO), 2025); eEML - Electronic Essential Medicines List (World Health Organization (WHO), 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.