Ivermectin Side Effects for Humans: What Happens More and Less Frequently

side effects from taking Ivermectin tablets

Ivermectin for humans is approved in most countries of the world for the treatment of parasitic, viral, and inflammatory diseases. This medicine has demonstrated high effectiveness in fighting against parasitic worms, river blindness, scabies, pediculosis, etc.

By its pharmacokinetic properties, Ivermectin can block the transmission of neuromuscular impulses, causing paralysis and further death of harmful microorganisms. Despite its low toxicity, side effects from taking Ivermectin tablets in people with weakened immune defences are possible. As official medicine has determined, side effects occur due to weakened immunity, and the nervous system is suppressed by the active substance Ivermectin. The mildest Ivermectin adverse effects are dizziness, drowsiness, and loss of concentration.

You should consult a doctor if, after taking Ivermectin, you have difficulty breathing, swelling of the face and lips, and urticaria.

In rare cases, the following Ivermectin adverse events may occur:

  • Muscle pain;
  • Nausea;
  • Diarrhea;
  • Rapid heartbeat;
  • Shortness of breath;
  • Muscle cramps;
  • Loss of consciousness;
  • Bladder or bowel disorders;
  • Redness or swelling of the eyes.

If any of the listed Ivermectin adverse reactions occur, you should immediately consult a doctor.

How long do Ivermectin side effects last

All side effects from taking Ivermectin have a relatively short-term effect (from 1 hour to 1-2 days).

Side effects such as skin redness, dizziness, and loss of visual acuity disappear after a few hours by themselves. Such rare side effects as muscle pain, urticaria, difficulty breathing, and loss of consciousness can often last long. Also, the fact how long Ivermectin side effects last depends on the state of the human immune system, as well as the presence of concomitant diseases.

You should also correctly calculate the dose to avoid the mass of Ivermectin, which can be harmless to your body. Consult a doctor if you have one of the listed side effects, and also stop taking Ivermectin until you get a doctor’s consultation.

Long-term side effects of Ivermectin in humans

Long-term effects of Ivermectin usually last up to 2 days. In rare cases: if there is an acute reaction of the body to Ivermectin and its components, as well as an overdose, more prolonged side effects can manifest.
Long-term side effects of ivermectin in humans may concern:

  • muscle and joint pain;
  • nervous system irritation;
  • headaches;
  • eyeballs inflammation;
  • eye tumours;
  • intestinal and bladder disorders.

As a rule, this body reaction to Ivermectin is rare (nearly 6-10 cases per 100,000 people). Most adults and children over 12 tolerate taking Ivermectin with almost no side effects.

How long does Ivermectin stay in your system?

An incredible fact answers the question – how long does Ivermectin stay in your system? Studies prove that ivermectin-based drugs remain in the human circulatory system for 18 hours. At the same time, part of this drug continues to be in the intestine for 12 days, during which the substance fights parasites. It means that the drug is no more influencing your vascular and nervous system but is still doing its job combating bacteria in the intestine.

The peak plasma concentration of this drug occurs 4 hours after oral administration. The drug is metabolized in the liver, and its decay products are excreted in 12 days through faeces (99%) and urine (1%).

Ivermectin side effects on kidneys

In healthy people who do not have kidney problems, Ivermectin does not cause side effects. Unlike many other antiparasitic and antiviral drugs, this drug is not excreted by the kidneys.

Doctors recommend taking Ivermectin therapy with caution if you have kidney disease. Especially if you have renal impairment, depending on the degree of renal dysfunction, the doctor may prohibit you from taking Ivermectin.

Most often, dose adjustment of Ivermectin occurs in the elderly due to aging changes in kidney function that occur after 65 years.


Like other antiparasitic and antiviral drugs, Ivermectin can provoke side effects. This medication has several contraindications that must be strictly observed to avoid an adverse reaction of the body to the active substance and other components of Ivermectin.

The most frequent adverse reactions – dizziness, redness of the skin, nausea, rapid breathing, and a feeling of physical fatigue, go away on their own after a few hours. More severe side effects can occur if you incorrectly violate the dosage and ignore the main contraindications that the manufacturer indicates in the leaflet of Ivermectin.

If the pain in the muscles and joints and disorders in the liver and kidneys after taking Ivermectin to last more than 1-2 days, you should stop taking the medication and consult a doctor.