Albendazole: what it treats, how to take it, side effects
Last updated September 3, 2026.
Albendazole (brand name Albenza) is a broad-spectrum deworming pill. It treats serious tissue infections like neurocysticercosis (pork tapeworm larvae in the brain) and hydatid disease (dog tapeworm cysts), and it is also the standard answer for everyday worm infections like roundworm and pinworm.
What does it treat?
In the US label, it treats neurocysticercosis and cystic hydatid disease of the liver, lung, and peritoneum. Worldwide and off-label, it is first-line for roundworm, hookworm, whipworm, pinworm, and strongyloidiasis. It starves the worm by blocking its glucose uptake, killing it over days.
How do you take it?
Take it with food; a fatty meal multiplies absorption several-fold, which matters for tissue infections. For patients 60 kg and over, the labeled dose is 400 mg twice daily. Courses vary by infection: neurocysticercosis runs 8 to 30 days, hydatid disease runs 28-day cycles separated by 14-day breaks for three cycles, and common intestinal worms often need only a single 400 mg dose. Missed dose: take it when remembered unless the next dose is near; never double up. Long courses come with blood-count and liver-enzyme monitoring.
Side effects to know
- Common: nausea, abdominal pain, headache, dizziness, and reversible hair thinning with long courses.
- Serious: bone marrow suppression (low blood counts) and liver enzyme elevations on prolonged treatment, both monitored with labs; allergic reactions; and in neurocysticercosis, the dying cysts themselves can provoke inflammation, which is why steroids and seizure coverage often accompany treatment.
Who should not take it?
Pregnancy comes first on the list: a negative pregnancy test precedes treatment, contraception covers treatment plus 3 days after, and it stops if pregnancy occurs, because of fetal-harm risk. Liver disease calls for caution and monitoring. Cimetidine, dexamethasone, and praziquantel all change albendazole levels, so the full medication list matters. Retinal involvement must be excluded before treating neurocysticercosis, since dying cysts in the eye can damage vision.
When is it an emergency?
Call 911 for seizures, sudden severe headache with vomiting (especially during neurocysticercosis treatment), signs of a severe allergic reaction, or yellowing of the eyes with dark urine and confusion. Fever with severe sore throat on a long course can signal low blood counts and needs same-day labs. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why must albendazole be taken with food?
Albendazole absorbs poorly on an empty stomach, and a meal, especially one with fat, multiplies blood levels several-fold. For intestinal worms that barely matters, since the drug works in the gut, but for tissue infections like neurocysticercosis and hydatid disease, the food rule is the difference between treatment and placebo.
How long does it take to kill the worms?
Common intestinal worms often clear with one dose or a few days. Tissue infections are slower: neurocysticercosis courses run 8 to 30 days and hydatid disease three 28-day cycles. Imaging and symptoms, not the calendar, judge tissue cures, so follow-up scans are part of the treatment.
Can I take albendazole while pregnant?
No, unless a specialist judges there is no alternative. The label requires a negative pregnancy test before starting, contraception during treatment and for 3 days after the last dose, and immediate discontinuation if pregnancy occurs, because of the risk of harm to the fetus.
Why am I also on steroids with this?
In neurocysticercosis, killing the cysts releases antigen that inflames the brain around them, which can trigger or worsen seizures and swelling. A steroid like dexamethasone, and often an anti-seizure medicine, runs alongside albendazole precisely to blunt that reaction. Skipping the steroid is not the safer move.
What lab monitoring does it need?
For short courses, none routinely. For the multi-week courses used in tissue disease, blood counts and liver enzymes are checked at the start of each cycle and during treatment, because bone marrow suppression and liver injury are the two real risks. Fever plus sore throat on treatment is a same-day call.
Does one dose treat pinworm?
One 400 mg dose, then typically a second dose 2 weeks later to catch newly hatched worms, since the drug kills worms but not eggs. Treating the whole household at once, washing bedding hot, and short fingernails are what stop the reinfection loop that makes pinworm feel unbeatable.