Overdo sing on ivermectin

Dear Dr Mac,

Some farmers in my area are taking ivermectin as they feel it offers protection against COVID-19. My son, who is a farmer, also took it some time ago for the same reason. He passed out when he was with a neighbour. Brain scans revealed nothing. However, the small print of the ivermectin states it could cause seizures.

He is also experiencing memory problems and poor concentration since he passed out. (He stopped taking ivermectin after he passed out.) I have also read that it remains in your body for three months after you stop taking it. Could you please advise? Kind regards,

Anonymous

Dear Anonymous,

Ivermectin is used mainly for treatment of parasitic diseases in both animals and humans. While there is some evidence that it may be effective against RNA viruses, it has not been registered for treating the coronavirus (SARS- CoV-2) in humans or animals at the present time. Ivermectin, at the correct dose, is used in human medicine for treating specific parasitic diseases (onchocerciasis and lymphatic filariasis) found in tropical climates. It’s not the drug itself that is toxic, but rather overdosing on it. Ivermectin is also deadly to dogs, cats, sheep, goats, cattle and pigs when too much is given.

According to the label on the ivermectin 1% injection (registered as a paracide for use in livestock), the withdrawal time for slaughter is 21 days for sheep and cattle. This means the drug remains in the meat at levels considered dangerous for human consumption for 21 days. One of the main signs of overdose in both humans and animals is seizures.

Not only are people overdosing, but they are also using animal remedies in which ivermectin is combined with other medications that are much more dangerous to both human and animal health when given as an overdose.

The damage to the brain due to ivermectin consumption may or may not be permanent; your son should see a specialist about this.

Neurological signs following ingestion or injection of ivermectin have been described in human patients, but the long-term effects will be specific to each patient.

I strongly advise people against using any drug or medication intended for animal use only. If you want to use ivermectin, contact a registered physician and use preparations registered for human use under the guidance of your physician. The most important principle to remember is that the dose of a specific medication is not usually the same for animals and humans, or even between different species of animals.

From an animal health perspective, I am seeing a huge shortage of ivermectin for animal use, which is resulting in unnecessary deaths in animals, especially sheep and goats, due to heavy loads of internal parasites. Kind regards,

Prof Cheryl McCrindle

• Cheryl McCrindle is an emeritus full professor in the Faculty of Veterinary Science at the University of Pretoria (UP). She has extensive experience in animal health, including livestock, small stock and poultry. She is also contracted to lecture in the School of Health Systems and Public Health at UP. Email her at farmersweekly@caxton.co.za. Subject line: Ask our vet.