Ivermectin or Fenbendazole With Opioids and Blood Thinners?

Thanks so much for looking out for your mom and checking on this before she takes anything new. We appreciate you reaching out to us.

The short answer is that this really needs to go through her doctor or pharmacist first. You don't mention what the blood thinner your mom is on, but ivermectin has a documented interaction concern with at least one common one (warfarin), and fenbendazole is a veterinary drug that isn't approved for people at all, so we simply don't have reliable human safety or interaction data for it.

On top of that, your mom is taking two strong opioids, and that combination deserves careful thought before adding anything with possible effects on the nervous system.

Ivermectin and Blood Thinners

Ivermectin (brand name Stromectol) is an FDA-approved antiparasitic medication used in humans for infections like strongyloidiasis and onchocerciasis. The most relevant interaction here involves warfarin.

The prescribing information notes rare post-marketing reports of an increased INR, which is the lab value used to measure how thin the blood is, when ivermectin was taken alongside warfarin. A higher INR means a higher bleeding risk.

Why Fenbendazole Raises Different Concerns

Fenbendazole is in a different situation entirely. It belongs to the benzimidazole class of antiparasitic drugs, and it is approved and studied only in animals, not in humans.

Since fenbendazole has never gone through human clinical trials, there is no established human dose, no human safety profile, and no reliable data on how it interacts with opioids or blood thinners. Related benzimidazoles that are approved for people, such as albendazole, can affect the liver and liver enzymes, which is at least a theoretical concern when combined with medications like warfarin that depend on the liver.

Overall though, we can't call fenbendazole safe with your mom's medications because the human data to answer that question doesn't exist.

Final Words

Given your mom's opioids and blood thinners, this is a situation where her doctor should review the specific blood thinner she takes, decide whether ivermectin is appropriate for her at all, and set up any monitoring that's needed.

As mentioned too, fenbendazole is not FDA approved for humans so I'm guessing it is not something her doctor suggested. I would not recommend using that drug at all without checking with her doctor first.

Thank you again for contacting us.