Ivermectin and Fenbendazole With Losartan and Lercanidipine

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Ivermectin doesn't have any well-documented, clinically significant interactions with losartan or lercanidipine, so from a strict interaction standpoint, that combination isn't a major concern.

Fenbendazole is a different situation entirely, though, and it deserves its own conversation...it's not approved for human use, so I'd really caution against using it.

How Ivermectin Fits With Your Blood Pressure Medications

Losartan is an angiotensin receptor blocker that lowers blood pressure by relaxing blood vessels, and lercanidipine is a dihydropyridine calcium channel blocker that works toward the same goal through a different mechanism.

Ivermectin is an antiparasitic that is broken down in the liver, mainly by the CYP3A4 enzyme, but it doesn't meaningfully block or speed up the enzymes that handle your blood pressure medicines, and neither losartan nor lercanidipine is expected to push ivermectin levels up in any important way.

In fact, ivermectin has very few documented drug interactions overall; the most notable one involves warfarin, a blood thinner you aren't taking (well, you at least didn't mention it in your question).

Keeping an Eye on Dizziness and Blood Pressure

One practical point is that ivermectin can occasionally cause dizziness, and drops in blood pressure on standing (postural hypotension) have been reported, particularly as part of the body's reaction to dying parasites in people treated for certain infections.

Since losartan and lercanidipine are already lowering your blood pressure, any added dip could show up as lightheadedness. It's sensible to stand up slowly for the first day or two after a dose and to mention any new dizziness to your doctor or pharmacist.

Why Fenbendazole Deserves Extra Caution

Fenbendazole is where I'd urge you to slow down.

It is a veterinary anthelmintic, approved for animals but not approved for human use in the United States, and its safety, dosing, and drug interactions in people simply haven't been well studied.

It belongs to the benzimidazole family, chemically related to human medicines like albendazole and mebendazole, but that relationship doesn't tell us how it behaves in a person taking blood pressure medications.

There have also been scattered case reports of liver injury in people who took fenbendazole on their own.

So, while I can't point to a specific interaction with losartan or lercanidipine, the honest answer is that we don't have good human data either way, and that gap itself is the concern.

Final Words

Ivermectin isn't expected to interact with losartan or lercanidipine, though watching for lightheadedness is wise, and keep in mind that ivermectin requires a prescription in the US. Fenbendazole isn't approved for people and hasn't been studied in this setting, so please talk with your doctor or pharmacist about why you want to take it before starting.

Feel free to reach out if you have any follow-up questions!