ALBENDAZOLE
Clinical safety rating: avoid
Contraindicated (not allowed)
Albendazole inhibits tubulin polymerization by binding to beta-tubulin, disrupting microtubule formation, which leads to impaired glucose uptake and depletion of glycogen stores in susceptible parasites, resulting in their immobilization and death.
| Metabolism | Primarily hepatic via microsomal enzymes; undergoes oxidation to albendazole sulfoxide (active metabolite) by CYP3A4 and flavin-containing monooxygenases (FMO). Further metabolized to albendazole sulfone (inactive) and other oxidative metabolites. |
| Excretion | Primarily renal (80%) as inactive metabolites; <2% unchanged in urine. Biliary/fecal excretion accounts for ~20%. |
| Half-life | Terminal half-life of albendazole sulfoxide is 8–12 hours; parent drug half-life is <1 hour. Clinical context: supports once- or twice-daily dosing. |
| Protein binding | 70% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.2–0.6 L/kg, indicating distribution into tissues; concentrates in liver, bile, and cerebrospinal fluid. |
| Bioavailability | Oral bioavailability is low (~5%) due to extensive first-pass metabolism; co-administration with a high-fat meal increases bioavailability up to 4–5-fold. |
| Onset of Action | Oral: clinical effect seen within 72 hours for parasitic clearance; peak plasma levels of active metabolite reached in 2–4 hours. |
| Duration of Action | Duration of action is approximately 24 hours after a single dose, necessitating daily dosing for 1–3 days depending on indication. |
| Action Class | Antiprotozoal agents |
| Brand Substitutes | Olworm 400mg Tablet, Zeebee Tablet, Zybend Tablet, Albekem 400mg Tablet, Sezole 400mg Tablet |
400 mg orally twice daily for 3-7 days for most indications; for neurocysticercosis, 400 mg orally twice daily for 8-30 days; for hydatid disease, 400 mg orally twice daily for 28-day cycles with 14-day drug-free intervals for 3 cycles.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. For severe renal impairment (CrCl <15 mL/min), use with caution; consider dose reduction or extended intervals. No specific GFR-based guidelines available. |
| Liver impairment | Contraindicated in patients with severe hepatic impairment (Child-Pugh class C). For mild to moderate impairment (Child-Pugh A or B), use with caution; monitor liver function. No specific dose adjustment guidelines available. |
| Pediatric use | For children >2 years: 15 mg/kg/day orally in 2 divided doses (max 800 mg/day) for most indications. For neurocysticercosis: 15 mg/kg/day orally in 2 divided doses (max 800 mg/day) for 8-30 days. For hydatid disease: 15 mg/kg/day orally in 2 divided doses (max 800 mg/day) for 28-day cycles with 14-day drug-free intervals. For children <2 years: safety and efficacy not established. |
| Geriatric use | No specific dose adjustment recommended; use with caution due to potential age-related hepatic or renal impairment. Monitor liver function and blood counts regularly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Cimetidine praziquantel and dexamethasone can increase albandinazole sulfoxide levels Bone marrow suppression is rare but possible monitor blood counts.
| Breastfeeding | Excreted in breast milk; M/P ratio not established. Use with caution, especially in neonates due to risk of bone marrow suppression. |
| Teratogenic Risk | FDA Category C. First trimester: risk of skeletal abnormalities and embryotoxicity based on animal studies. Second and third trimesters: limited human data, but potential for fetal harm; avoid use unless benefit outweighs risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
Albendazole may cause fetal harm when administered to pregnant women. It is contraindicated in pregnancy and should not be used in women who are or may become pregnant. Women of childbearing potential should have a negative pregnancy test before starting treatment and should use effective contraception during therapy and for one month after completion.
| Serious Effects |
["Pregnancy (absolute)","Known hypersensitivity to albendazole or any of its components","Patients with pre-existing bone marrow suppression (relative)"]
| Precautions | ["Bone marrow suppression: Monitor CBC at start and periodically; risk of pancytopenia, particularly in patients with hepatic disease or receiving high doses.","Hepatotoxicity: Monitor liver function tests due to risk of elevated transaminases and rare hepatic failure.","Risk of neurocysticercosis exacerbation: May cause increased intracranial pressure or seizures; treat with corticosteroids and anticonvulsants as needed.","Retinal damage: In ocular neurocysticercosis, evaluate for retinal lesions before therapy due to risk of retinal damage from inflammation.","Renal impairment: Use with caution; dose adjustment may be necessary.","Lactation: Excreted in breast milk; caution in nursing mothers."] |
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| Monitor liver function tests (LFTs) and complete blood count (CBC) with differential at baseline and periodically. Monitor for fetal growth and development via ultrasound if used during pregnancy. |
| Fertility Effects | Animal studies show reduced fertility and spermatogenesis at high doses. Human data limited; potential for reversible impairment of fertility in both sexes. |
| Food/Dietary |
| Take with a high-fat meal (≥40 g fat) to significantly increase oral bioavailability. Avoid grapefruit juice as it may affect drug metabolism. No specific dietary restrictions otherwise. |
| Clinical Pearls | Albendazole is a broad-spectrum anthelmintic that inhibits microtubule polymerization by binding to beta-tubulin. It is highly effective against Echinococcus granulosus cysts but requires prolonged therapy (e.g., 28-day cycles). Monitor liver function tests (LFTs) at baseline and every 2 weeks due to risk of hepatotoxicity. For neurocysticercosis, co-administer corticosteroids to reduce inflammatory reaction from cyst degeneration. Albendazole is pregnancy category C; avoid in first trimester and in women planning pregnancy within 1 month of therapy. Absorption is enhanced by a fatty meal; administer with a high-fat meal to increase bioavailability up to 5-fold. |
| Patient Advice | Take this medication with a fatty meal (e.g., eggs, avocado, nuts) to improve absorption. · Do not crush or chew the tablets; swallow them whole with water. · Complete the full course of therapy even if you feel better. · Report any signs of liver problems: yellowing of skin/eyes, dark urine, severe nausea, or abdominal pain. · Avoid pregnancy during treatment and for at least 1 month after the last dose; use reliable contraception. · You may experience dizziness or blurred vision; avoid driving or operating machinery until you know how the drug affects you. · If you are breastfeeding, discuss with your doctor before taking this medication. |