Ivermectin is one of the most important antiparasitic agents in history. It was developed from substances produced by a soil bacterium. Its discovery transformed the treatment of parasitic disease in humans and animals, and because its mechanism is so well understood it is also a useful tool in scientific research.
A Nobel-winning discovery
The substances ivermectin was made from were isolated from the soil bacterium Streptomyces avermitilis (studied by Satoshi Ōmura), and their ability to kill parasites was recognised by William Campbell's team. Ivermectin is an improved, safer version of them. For this discovery Campbell and Ōmura received the 2015 Nobel Prize in Medicine. The drug has protected millions of people from parasitic disease, including river blindness.
Structure
Ivermectin is a mixture of two very similar, complex molecules. It dissolves well in fats and poorly in water — which matters when preparing solutions in the laboratory.
How it works: it “switches off” the parasite
Ivermectin acts primarily on a particular kind of channel (tiny “gate”) in the nerve and muscle cells of parasites, known as GluCl chloride channels. Such channels occur only in invertebrates — worms and insects among them. Ivermectin opens them permanently. That leaves the parasite's cell “locked open”, so the parasite is paralysed and dies.
Why it is safe for mammals
Ivermectin's safety rests on two things. First, mammals (including humans) have no GluCl channels at all for the drug to act on. Second, the mammalian brain has a natural “bouncer” — a protein that actively pumps ivermectin out of the brain and stops it reaching sensitive sites in the nervous system.
An aside: some dog breeds (collies, for example) carry a genetic fault that makes this protective mechanism work less well — which is why they are far more sensitive to ivermectin. It is a good illustration of how important the body's internal “protection systems” are.
What happens to it in the body
Ivermectin is well absorbed and distributes through the tissues (apart from the protected brain), is processed in the liver and is excreted mainly in the faeces. It acts for a relatively long time.
What it works against, and where it is approved
Ivermectin kills both internal and external parasites. In humans it has narrow, precisely defined and approved uses (certain parasitic diseases and scabies among them). In animals it is used widely to prevent and treat parasites.
Use as a research reagent
Because its action is so well understood, ivermectin is sometimes used as a tool for studying cellular channels and as a reference standard in chemical analysis. SWISS LAB supplies it as a reagent of defined purity.
Sources
- The Nobel Committee (2015), The Nobel Prize in Physiology or Medicine 2015 — nobelprize.org
For in-vitro laboratory research only. It is not a human medicine and is not for treatment.