Ivermectin falls into the category of drugs known as macrocyclic lactone – a complex chemical with robust anti-parasitical action that exhibits high effectiveness in the treatment of worm infestations and excellent tolerability in both humans and animals.

Mechanism of action of Ivermectin for Humans

Ivermectin causes the paralysis and death of parasites through selective binding and high affinity for glutamate-gated chloride channels found in the nerve and muscle cells of invertebrates. In the absence of glutamate-gated chloride channels in mammals, ivermectin does not produce any toxic effect on the human central nervous system, in which similar channels are protected by the blood-brain barrier.

The mechanism of action of ivermectin in the treatment of inflammatory skin lesions like rosacea may be associated with both the drug’s significant anti-inflammatory effect that suppresses the production of inflammatory cytokines induced by lipopolysaccharides or its ability to kill Demodex folliculorum mites, which might be a factor causing skin inflammation.

Both brand-name and generic ivermectin are available as oral 3mg tablets. The correct dose of ivermectin is determined with regard to the patient’s specific health problem, age, concomitant diseases, and other essential factors. Below are some general recommendations on the possible ivermectin dosing regimen.


  • 15-24 kg: 3mg
  • 25-35 kg: 6mg
  • 36-50 kg: 9mg
  • 51-65 kg: 12mg
  • 66-79 kg: 15mg
  • Over 80 kg: 200mcg/kg

All of the above doses need to be taken orally once. No repeat dose is usually required.


  • 15-25 kg: 3mg
  • 26-44 kg: 6mg
  • 45-64 kg: 9mg
  • 65-84 kg: 12mg
  • Over 85 kg: 150mcg/kg

All of the above doses need to be taken orally once. A repeat dose might be required in 3 to 12 months after the first dose.

Ascariasis and Larva Migrans:

0.2mg/kg orally once


0.2mg/kg orally once


0.2mg/kg orally once, with a repeat dose in 14 days. Also, patients might be advised to combine oral medicine with a topical pyrethroid.

Ivermectin tablets are best taken on an empty stomach with a glass of water, usually, 1 hour before breakfast unless otherwise is specified by the prescribing physician. Patients should take only as much of this drug as recommended by the doctor. If they suspect they may have overdosed on ivermectin, patients should seek urgent medical care right away.

Drug interactions

Ivermectin can have mild-to-moderate interactions with a wide range of brand-name drugs and OTC generic medications. However, there have been no reports of serious or critical reactions. Some of the drugs ivermectin should be taken cautiously with include:

  • central nervous system depressants (butalbital, phenobarbital)
  • anticonvulsants (valproic acid)
  • benzodiazepines (lorazepam, clonazepam)
  • narcolepsy drugs (sodium oxybate)
  • blood-thinners (warfarin).

Patients on ivermectin should also avoid using alcohol alongside this drug, as this combination can cause increased plasma levels of ivermectin, making the possible side effects more adverse, complex, and prolonged.