albendazole (Rx)

>10%

Headache

• Neurocysticercosis (11%)
• Hydatid disease (1.3%)

Abnormal LFT

• Hydatid disease (15.6%)
• Neurocysticercosis (<1%)

1-10%

Abdominal pain

• Hydatid disease (6%)

Nausea/vomiting

• Hydatid disease (3.7%)
• Neurocysticercosis (6.2%)

Dizziness/vertigo

• Hydatid disease (1.2%)
• Neurocysticercosis (<1%)

Increased intracranial pressure

• Neurocysticercosis (1%)

Meningeal signs

• Neurocysticercosis (1%)

Alopecia (reversible)

• Hydatid disease (1.6%)
• Neurocysticercosis (<1%)

Fever

• Hydatid disease (1%)

<1% (selected)

Rash

Urticaria

Agranulocytosis

Aplastic anemia

Bone marrow suppression

Granulocytopenia

Pancytopenia

Thrombocytopenia

Hepatitis

Acute liver failure

Acute renal failure

Contraindications

Hypersensitivity to albendazole or benzimidazoles

Cautions

Monitor theophylline levels if used concomitantly

Potential for bone marrow suppression, aplastic anemia & agranulocytosis; monitor blood counts in all patients at the beginning of each 28-day cycle of therapy, and every 2 weeks while on therapy; discontinue therapy if clinically significant changes in blood counts occur

Pre-existing neurocysticercosis may be uncovered in patients treated w/ albendazole for other conditions, apparent by neurological symptoms (eg, seizures, increased intracranial pressure, focal signs); promptly treat w/ corticosteroid & anticonvulsant therapy

Obtain pregnancy test in women of reproductive potential prior to therapy and avoid usage in pregnant women except in clinical circumstances where no alternative management is appropriate; discontinue therapy if pregnancy occurs and apprise patient of potential hazard to fetus

Risk of retinal damage in retinal cysticercosis; cases of retinal involvement reported; examine patient for presence of retinal lesions before initiating therapy for neurocysticercosis

Reversible elevations of liver enzymes may occur; monitor liver enzymes before start of each treatment cycle and at least every 2 weeks while on therapy and discontinue if clinically significant elevations occur; patients with abnormal LFTs and hepatic echinococcosis are at increased risk of hepatotoxicity; discontinue therapy if LFT elevations >2 times upper limit of normal; may consider restarting treatment when LFT values return to pretreatment levels

Pregnancy

Based on findings from animal reproduction studies, the drug may cause fetal harm when administered to a pregnant woman; however, available human data from a small number of published case series and reports on use of multiple-dose in the first trimester of pregnancy, and several published studies on single-dose use later in pregnancy, have not identified any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes

Pregnancy testing recommended for females of reproductive potential prior to initiating therapy

Contraception

• Females: May cause fetal harm when administered to a pregnant woman; advise females of reproductive potential to use effective contraception during treatment and for 3 days after final dose

Animal data

• In animal reproductive studies, oral administration of albendazole during period of organogenesis caused embryotoxicity and skeletal malformations in pregnant rats (at doses of 0.10 times and 0.32 times the maximum recommended human dose based on body surface area in mg/m²) and pregnant rabbits (at doses of 0.60 times the maximum recommended human dose based on body surface area in mg/m²); drug was also associated with maternal toxicity in rabbits (at doses of 0.60 times recommended human dose based on body surface area in mg/m²); advise a pregnant woman of potential risk to fetus

Lactation

Concentrations of drug and active metabolite, albendazole sulfoxide, reported to be low in human breast milk; there are no reports of adverse effects on breastfed infant and no information on effects on milk production

Developmental and health benefits of breastfeeding should be considered along with mother’s clinical need nd any potential adverse effects on breastfed infant from drug or from underlying maternal condition

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Causes degeneration of cytoplasmic microtubule in intestinal and tegmental cells of intestinal helminths

Pharmacokinetics

Absorption: <5%; may increase up to 4-5 times with a fatty meal

Distribution: Well inside hydatid cysts & CSF

Protein Bound: 70%

Metabolism: Hepatic; extensive first-pass effect; pathways include rapid sulfoxidation (major), hydrolysis, & oxidation

Half-life: 8-12 hr

Peak Plasma Time: 2-5 hr

Excretion: urine (<1% as active metabolite); feces