Albendazole is a broad-spectrum antiparasitic tablet that eliminates intestinal worms (roundworms, tapeworms, pinworms) and other parasites. It is also used for hydatid cysts and neurocysticercosis under medical supervision.
Also known as: Albenza, Zentel
Cimetidine may increase blood levels of the active albendazole metabolite (albendazole sulfoxide), potentially enhancing both therapeutic effect and side effects.
Cimetidine inhibits CYP3A4, reducing the metabolism of albendazole sulfoxide formed during first-pass hepatic metabolism.
Gastrointestinal symptoms and liver function tests during prolonged treatment.
Persistent nausea, abdominal pain, jaundice.
The combination is generally well tolerated; assess for signs of increased albendazole exposure (nausea, abdominal pain, raised transaminases).
DailyMed — Albendazole Tablet [Golden State] label (RLD Albenza), Drug Interactions: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8de337eb-92e1-15b5-e053-2a95a90ac4f1
Albendazole (and its active sulfoxide metabolite) bioavailability increases substantially when taken with a meal — especially a fatty one.
Take with a meal (ideally containing some fat) for maximum efficacy.
EMC-UK — Albendazole SmPC 4.2/4.5 (absorption increased with food); DailyMed Albenza (fatty meal).
Albendazole is teratogenic in animals in the 1st trimester — contraindicated in pregnancy unless clear benefit.
Effective contraception during treatment and for 1 month after; mass deworming: avoid in pregnant women.
Prontuário Terapêutico INFARMED, 1.4.1 (albendazole — teratogenicity); WHO mass deworming guidance.
Hepatic metabolism produces the active sulfoxide; in liver disease exposure rises and so does hepatotoxicity risk.
Monitor transaminases in long courses; discontinue if elevation > 2–3× ULN.
Prontuário Terapêutico INFARMED, 1.4.1 (albendazole — hepatic monitoring in long courses).
Benzimidazole inhibiting tubulin polymerisation — theoretically embryotoxic mechanism. The Prontuário has no dedicated Annex 1 entry (avoid as precaution in all trimesters, especially the 1st); human data are limited, but mass-treatment studies (WHO) showed no increase in malformations. EMC-UK: "women should be warned of the potential risk and pregnancy avoided" during and for 1 month after.
Avoid in all trimesters; treat before pregnancy or defer until after the 1st trimester if clinically possible. Pregnancy test beforehand if possible.
Contraindicated (Prontuário, Annex 2, l. 42180): "Albendazole — Contraindicated".
Avoid pregnancy during treatment and for 1 month after (EMC-UK); effective contraception in women of child-bearing potential.
Prontuário Terapêutico INFARMED — Annex 2: "Albendazole — Contraindicated" (l. 42180). EMC-UK (MHRA) — Albendazole SmPC (Zentel): https://www.medicines.org.uk/emc/product/1441/smpc (section 4.6).
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Broad-spectrum anthelmintic active against tissue nematodes, cestodes and trematodes; efficacy depends on systemic exposure to the active metabolite (sulfoxide), unlike other luminal-acting benzimidazoles.
Binds parasite β-tubulin and inhibits its polymerisation into microtubules, destroying cytoplasmic microtubules and blocking glucose uptake — the parasite dies of energy depletion. Also inhibits helminthic mitochondrial fumarate reductase.
Poorly absorbed orally when fasting (< 5%), increasing 3–5-fold with a fatty meal (the neurocysticercosis regimen recommends 40 g of fat at the dosing meal). Sulfoxide peaks in plasma at 2–5 h.
Rapid hydrolysis to sulfoxide via first-pass metabolism (CYP3A4 and flavin monooxygenase); sulfoxide is the active metabolite and undergoes further oxidation to inactive sulfone. Dexamethasone/cimetidine raise sulfoxide concentrations; inducers (carbamazepine, phenytoin) lower them.
Sulfoxide: 8–12 h (prolonged in cysticercosis via enterohepatic recirculation); sulfone: ~10 h.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
