Levamisole uses: what it’s used for now and what it used to treat

Levamisole started life as a deworming drug and still does that job in animals. Over time people discovered other actions — effects on the immune system and even cancer — so it popped up in several areas of medicine. That history makes the story messy: some uses are common and safe, others were stopped because the risks became clear.

Common and current uses

Today you’ll commonly see levamisole used in veterinary medicine to treat parasitic worm infections in livestock and pets. It’s inexpensive and effective for some types of worms.

In human medicine, levamisole has a narrower role. One useful modern application is as a steroid-sparing agent for children with steroid-dependent nephrotic syndrome (a kidney condition that causes heavy protein loss in urine). In those cases doctors sometimes use low-dose levamisole to reduce steroid exposure and help keep kids in remission. That’s a targeted, supervised use done by specialists.

Historically, levamisole was combined with chemotherapy (like 5‑fluorouracil) for colon cancer in the 1990s as an immune-system booster. Over time the cancer benefit was questioned and safety concerns grew, so that practice largely stopped in many countries.

Risks, side effects, and safety tips

Levamisole can cause serious side effects, so it’s not a take-home, over-the-counter fix. The most dangerous issue is agranulocytosis — a very low white blood cell count that leaves you open to severe infections. Watch for fever, sore throat, mouth sores, or unusual bruising; these are red flags that need urgent medical attention.

Other known problems include skin reactions and a small but real risk of a vasculitis-like syndrome (blood vessel inflammation) that can cause skin ulcers or necrosis. When levamisole shows up as a contaminant in illegal drugs such as cocaine, it has been linked to severe skin damage and immune problems — a public health issue in recent years.

If a doctor prescribes levamisole, follow their instructions and get blood tests as requested. If you’re buying drugs online, never take levamisole or similar medicines without a valid prescription and a reliable pharmacy. Check pharmacy accreditation tools like CIPA or PharmacyChecker if you’re unsure about an online seller.

Anyone who suspects accidental exposure — for example, if they used a street drug that might be cut with levamisole — should seek medical help right away, especially with fever, severe skin changes, or signs of infection.

Bottom line: levamisole still has useful roles, mainly in animals and select human conditions under specialist care. But it carries serious risks that mean it must be used carefully, with proper medical oversight and monitoring.