Parasite treatments: clear options, safety tips, and when to act

Got stomach pain, itchy bottom at night, or persistent diarrhea after travel? Those can be signs of a parasite. Parasites come in a few main types — worms (helminths), single-celled bugs (protozoa), and surface pests like lice or scabies. The right treatment depends on the bug, so knowing what to expect helps you get better faster.

Common treatments and what they do

Mebendazole (often sold as Vermox) and albendazole are the go-to drugs for many intestinal worms. For example, a single 100 mg mebendazole dose is commonly used for pinworms, though your doctor may use a different schedule. Praziquantel treats tapeworms and schistosomiasis. Ivermectin works well for strongyloides and certain ectoparasites; permethrin cream is the usual topical choice for scabies and lice.

Protozoal infections like giardia or entamoeba are often treated with metronidazole or tinidazole. These clear the infection but can cause nausea, metallic taste, or dizziness for some people. Antibiotics aren’t helpful for worms — only specific antiparasitic drugs work.

Testing, dosing, and safety basics

Don’t guess the treatment. Tests that find parasites include stool ova-and-parasite exams, stool antigen or PCR tests, and sometimes blood tests or imaging for certain worms. Your provider will pick the right test and medicine. Dosing varies by parasite, age, weight, and pregnancy status, so follow the prescription closely.

Some meds aren’t safe in pregnancy (albendazole and praziquantel have restrictions). Metronidazole interacts with alcohol — avoid drinks while on it and for a short time after. Side effects vary: mild stomach upset, headache, or dizziness are common. Serious reactions are rare but require immediate care.

If you’re treating household members for pinworms or scabies, follow the full guidance: treat close contacts, wash bedding and clothes, and clean surfaces. For travel-related risks, boil or filter water, avoid raw seafood or undercooked meat, and use shoes on beaches in endemic areas.

When should you see a doctor now? High fever, severe belly pain, bloody stool, rapid weight loss, fainting, or symptoms in a pregnant person mean seek care right away. Also see a doctor if over-the-counter or initial treatments don’t clear symptoms within a few days to weeks, depending on the bug.

Short version: identify the parasite with testing, use a targeted drug, follow safety rules, and treat close contacts when needed. If in doubt, get a medical exam — the right diagnosis saves time and prevents complications.