Albendazole

Trade Names:Albenza- Tablets 200 mg

Pharmacology

Inhibits effect on tubulin polymerization, resulting in loss of cytoplasmic microtubules.

Pharmacokinetics

Absorption

Albendazole is poorly absorbed from the GI tract; however, it is rapidly converted to its primary active metabolite, albendazole sulfoxide, prior to reaching systemic circulation. Fatty meals enhance bioavailability, as indicated by up to a 5-fold increase in plasma concentration in albendazole sulfoxide. Albendazole sulfoxide plasma concentrations are dose dependent. C _max is achieved in 2 to 5 h and ranges from 0.46 to 1.58 mcg/mL, with a fatty meal.

Distribution

Albendazole sulfoxide is 70% protein bound and widely distributed throughout the body.

Metabolism

After metabolism in the liver to albendazole sulfoxide, it is further metabolized to albendazole sulfone and other oxidative metabolites.

Elimination

Albendazole sulfoxide elimination t _½ is 8 to 12 h. Biliary elimination of albendazole sulfoxide results in biliary concentrations similar to plasma concentration. Urinary excretion is a minor elimination pathway (less than 1%).

Special Populations

Systemic availability of albendazole sulfoxide is increased in patients with extrahepatic obstruction.

Indications and Usage

Treatment of parenchymal neurocysticercosis caused by larval forms of pork tapeworm, Taenia solium ; treatment of cystic hydatid disease of the liver, lung, and peritoneum caused by larval forms of dog tapeworm, Echinococcus granulosus .

Contraindications

Hypersensitivity to benzimidazole compounds or any component of the product.

Dosage and Administration

PO For patients weighing 132 lb (60 kg) or more, administer 400 mg twice daily with meals for a 28-day cycle followed by a 14-day albendazole-free interval, for a total of 3 cycles. For patients weighing less than 132 lb (60 kg), administer 15 mg/kg/day in divided doses twice daily with meals (max, 800 mg/day) for a 28-day cycle followed by a 14-day albendazole-free interval, for a total of 3 cycles. In the presurgical or postsurgical setting, optimal killing of cyst contents is achieved with 3 courses of therapy.

PO For patients weighing 132 lb (60 kg) or more, administer 400 mg twice daily with meals for 8 to 30 days. For patients weighing less than 132 lb (60 kg), administer 15 mg/kg/day in divided doses twice daily with meals (max, 800 mg/day) for 8 to 30 days.

General Advice

• Albendazole should be taken with food.
• If difficulty swallowing the tablets occurs, tablets may be crushed or chewed with a little water.

Storage/Stability

Store between 68° and 77°F.

Drug Interactions

In hydatid cyst patients, albendazole sulfoxide concentrations in bile and cystic fluid may be increased about 2-fold; however, plasma levels are unchanged 4 h after dosing.

Albendazole C _trough at steady state was about 56% higher when coadministered with dexamethasone 8 mg.

Plasma concentrations may be elevated and the t _½ may be shortened.

Albendazole sulfoxide C _max may be elevated about 50%, increasing the risk of adverse reactions.

Although theophylline pharmacokinetics are unchanged by albendazole, monitor plasma concentrations during and after albendazole treatment.

Laboratory Test Interactions

None well documented.

Adverse Reactions

CNS

Headache (11%); raised intracranial pressure (2%); dizziness/vertigo, meningeal signs (1%).

Dermatologic

Reversible alopecia (2%); erythema multiforme, hypersensitivity including rash and urticaria (less than 1%); Stevens-Johnson syndrome (postmarketing).

GI

Abdominal pain, nausea/vomiting (6%).

Genitourinary

Acute renal failure (postmarketing).

Hepatic

Abnormal LFTs (16%); hepatitis (postmarketing).

Hematologic-Lymphatic

Leukopenia (less than 1%); agranulocytosis, granulocytopenia, pancytopenia, thrombocytopenia (rare); aplastic anemia (postmarketing).

Miscellaneous

Fever (1%).

Precautions

Pregnancy

Category C .

Lactation

Undetermined.

Children

Experience in children younger than 6 yr of age is limited.

Bone marrow suppression

Rare deaths due to granulocytopenia or pancytopenia have been reported.

Co-therapy

Patients being treated for neurocysticercosis should receive appropriate steroid and anticonvulsant therapy as needed. Consider using oral or IV corticosteroids to prevent cerebral hypertensive episodes during the first week of therapy.

Overdosage

Symptoms

No untoward effects have been reported with doses of at least 16 g over 12 h.

Patient Information

• Advise patient that drug may cause fetal harm and to begin therapy after a negative pregnancy test has been obtained.
• Caution women of childbearing age to avoid becoming pregnant while on this drug or within 1 mo of completing treatment.
• Advise patient that if pregnancy occurs while taking this drug, to contact health care provider immediately.

Copyright © 2009 Wolters Kluwer Health.