Albendazole

Key facts

• Albendazole is a benzimidazole antiparasitic that treats roundworm, hookworm, whipworm, pinworm, and several tapeworm infections, including hydatid disease.
• For intestinal worms it's usually a short course of one to three days; for tissue infections like hydatid disease or neurocysticercosis, treatment runs for weeks and is taken with a fatty meal to boost absorption.
• Albendazole is teratogenic in animal studies and is avoided in pregnancy, especially the first trimester; longer courses are usually preceded by a pregnancy check, and reliable contraception is advised during and shortly after treatment.
• Longer courses need blood tests for liver function and blood counts, since albendazole can cause liver injury and suppress bone marrow.

What albendazole treats

Albendazole treats intestinal worm infections, including roundworm (ascariasis), hookworm, whipworm, and pinworm, as well as tapeworm infections. It also treats hydatid disease, cysts caused by tapeworm larvae in the liver or lungs, and neurocysticercosis, larval cysts in the brain, usually as part of specialist care.

How albendazole works

Albendazole binds to structural proteins inside parasitic worms, disrupting their internal skeleton, and this also stops the worms taking up glucose, their main energy source. Without energy or structure, the parasites die and are cleared from the gut, or in tissue infections, from the cysts they have formed.

Before you take it

• Avoid albendazole in pregnancy, particularly the first trimester, because of the birth defects seen in animal studies; use reliable contraception during treatment and for a month after, and tell your doctor if pregnancy is possible.
• Tell your doctor about liver disease before starting; expect liver function tests before and during longer courses.
• For neurocysticercosis, a corticosteroid and an anti-seizure medicine are usually given alongside albendazole, since dying larvae in the brain can trigger inflammation, swelling, and seizures.
• Tell your prescriber about other medicines, since some antiepileptics and cimetidine change albendazole levels.

Side effects

Common effects include headache, nausea, abdominal pain, and dizziness, usually mild and short-lived with brief courses.

Stop and seek urgent medical care for any of these:

• Yellowing of the skin or eyes, dark urine, or persistent fatigue, which can signal liver injury.
• Unusual bruising, bleeding, a sore throat that will not go away, or fever, which can signal a drop in blood cell counts.
• Confusion, seizures, or loss of coordination.
• Facial or throat swelling, or difficulty breathing.

Safety essentials

• Avoid albendazole in pregnancy, especially the first trimester, given its teratogenic potential in animal studies; confirm you are not pregnant before starting longer or repeated courses.
• Blood counts and liver function tests are checked before and during extended treatment, such as for hydatid disease, since albendazole can suppress bone marrow and injure the liver.
• If you are treated for neurocysticercosis, take any prescribed corticosteroid and anti-seizure medicine alongside albendazole exactly as directed, since skipping them raises the risk of a dangerous inflammatory reaction in the brain.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.