What are the dosing regimens, contraindications, side effects, and drug interactions of albendazole for various parasitic infections in adults and children?

Albendazole: Dosing, Safety, and Clinical Management

Standard Dosing Regimens

For most common intestinal helminth infections in adults and children over 24 months, albendazole 400 mg as a single oral dose is the standard treatment. 1, 2

Single-Dose Regimens (400 mg)

• Ascariasis (roundworm): 400 mg single dose achieves 95% cure rate 1, 2, 3
• Enterobiasis (pinworm): 400 mg single dose, repeat in 2 weeks to eliminate reinfection 1, 2
• Hookworm (initial): 400 mg single dose achieves 78% overall cure rate (92% for Ancylostoma duodenale, 75% for Necator americanus) 3

Multi-Day Regimens

• Hookworm (complete eradication): 400 mg daily for 3 days 1, 4
• Whipworm (Trichuris trichiura): 400 mg daily for 3 days (achieves only 48% cure with single dose) 1, 3
• Strongyloidiasis (alternative to ivermectin): 400 mg twice daily for 3-7 days 4, 2
• Taenia species: 400 mg daily for 3 days 2

Specialized Infections Requiring Higher/Prolonged Dosing

• Neurocysticercosis (1-2 cysts): 15 mg/kg/day divided twice daily for 10-14 days (maximum 1200 mg/day) plus corticosteroids 1, 2
• Neurocysticercosis (>2 cysts): 15 mg/kg/day plus praziquantel 50 mg/kg/day for 10-14 days, both divided twice daily plus corticosteroids 5, 1
• Visceral larva migrans (Toxocariasis): 400 mg twice daily for 5 days 5, 4
• Ocular toxocariasis: 400 mg twice daily for 3-14 days depending on severity, requires ophthalmology co-management 5
• Gnathostomiasis: 400 mg twice daily for 21 days 1
• Loiasis (high microfilarial loads): 400 mg daily for 10-28 days; may increase to 800 mg daily if treatment fails 4
• Microsporidiosis (Encephalitozoon intestinalis): 7.5 mg/kg twice daily (maximum 400 mg/dose) until immune reconstitution 1, 4

Pediatric Dosing

• Children >24 months (>15 kg): Use standard adult dose of 400 mg 1
• Children 12-24 months (≤15 kg): 400 mg may be used for ascariasis or trichuriasis only when epidemiologically justified; expert consultation required before treating asymptomatic eosinophilia 1

Critical Administration Requirements

Albendazole must always be taken with food, preferably a fatty meal, to maximize absorption. 1, 2 The tablet may be crushed or chewed and swallowed with water for pediatric patients. 2

Avoid liquid paraffin (mineral oil) during treatment as it significantly impairs absorption. 1

Absolute Contraindications and Pre-Treatment Screening

Mandatory Pre-Treatment Assessments

• Fundoscopic examination: Required before all neurocysticercosis treatment to exclude retinal cysticercosis 1, 2
• Loa loa screening: Mandatory in patients from Central/West Africa before co-administering ivermectin, as severe encephalopathy can occur 1, 4, 2
• Strongyloides screening: Essential before prolonged corticosteroid therapy, as hyperinfection syndrome is fatal 1, 2
• Latent tuberculosis screening: Recommended when extended corticosteroid treatment is anticipated 1

Contraindications to Treatment

• Active hepatic disease: Avoid due to hepatotoxicity risk 1
• Pre-existing leukopenia: Use with extreme caution as albendazole causes leukopenia in up to 10% of patients 1
• Pregnancy: Use only when therapeutic benefit clearly outweighs fetal risk 1
• Untreated hydrocephalus or diffuse cerebral edema in neurocysticercosis: Do not administer antiparasitic drugs until intracranial pressure is managed 1

Monitoring Requirements

For Treatment Courses >14 Days

Perform complete blood count and liver function tests at the start of each 28-day cycle and every 2 weeks during therapy. 1, 2 Elevated liver enzymes occur in up to 16% of patients, requiring discontinuation in approximately 3.8%. 1 Leukopenia develops in up to 10% of patients. 1

For Single-Dose or Short Courses (<14 Days)

No routine laboratory monitoring is necessary. 1

Critical Drug Interactions

• Dexamethasone: Increases albendazole levels by approximately 56%, which may be therapeutically beneficial in neurocysticercosis, but reduces praziquantel levels due to increased metabolism 5, 1
• Praziquantel: Significantly increases albendazole exposure; co-administration is safe and commonly recommended without additional monitoring 1

Common Pitfalls and How to Avoid Them

• Loeffler's syndrome treatment: When no organism is identified, use empirical single-dose ivermectin 200 μg/kg plus albendazole 400 mg; consider retreatment 1 month after resolution to ensure adult worms are treated 5
• Schistosomiasis: Repeat albendazole dose at 8 weeks after initial treatment, as eggs and immature schistosomulae are relatively resistant 1
• Steroid use caution: Exercise extreme caution using steroids in suspected strongyloidiasis, as they may precipitate fatal hyperinfection 5
• Neurocysticercosis management: Always start corticosteroids before initiating antiparasitic therapy to reduce inflammatory complications 1
• Intestinal Taenia solium: Prefer niclosamide 2g over praziquantel unless neurocysticercosis has been definitively excluded 5, 4

Side Effects Profile

Albendazole has a remarkable safety record with several hundred million patient exposures over 20 years. 3 Gastrointestinal side effects occur with an overall frequency of just over 1%. 3 Side effects are generally mild and transient, with no evidence of toxic effects on bone marrow, heart, liver, or kidneys in short-course therapy. 6