Pharmacology of Albendazole


Albendazole is a member of the benzimidazole derivatives and is a broad-spectrum anthelmintic agent. It is widely recognized for its effectiveness against a variety of parasitic worms, including those affecting the gastrointestinal tract and tissues. Its use spans both human and veterinary medicine, addressing numerous parasitic infections.

Chemical Structure and Properties


Albendazole is chemically known as methyl [5-(propylthio)-1H-benzimidazol-2-yl]carbamate. It appears as a white to off-white powder with poor solubility in water and most organic solvents, but it is soluble in dimethyl sulfoxide. This solubility profile influences its pharmacokinetic behavior and administration.

Mechanism of Action

The primary mechanism of albendazole involves the inhibition of tubulin polymerization, leading to the loss of cytoplasmic microtubules within the cells of the worms. This disruption affects the transport of glucose and other substances, leading to a depletion of energy stores and eventual death of the parasite.


  • Absorption: Albendazole has low oral bioavailability due to its limited solubility. However, absorption is significantly enhanced when taken with a fatty meal, which increases its solubility.
  • Distribution: It is widely distributed in the body, reaching various tissues including the liver, bile, cerebrospinal fluid, and urine.
  • Metabolism: It is primarily metabolized in the liver to albendazole sulfoxide, an active metabolite that retains anthelmintic activity.
  • Excretion: The drug and its metabolites are primarily excreted in the bile and, to a lesser extent, in the urine.
  • Clinical Uses
  • Intestinal Helminthiasis: Albendazole is effective against various intestinal worms such as Ascaris lumbricoides, hookworms, and Trichuris trichiura.
  • Tissue Helminthiasis: It is used in treating hydatid disease and neurocysticercosis, caused by the larval forms of Echinococcus granulosus (dog tapeworm) and Taenia solium (pork tapeworm), respectively.
  • Other Uses: There is ongoing research into its potential applications in treating protozoal infections and certain cancers.

Adverse Effects

  • While generally well-tolerated, albendazole can cause:

    • Gastrointestinal Symptoms: Nausea, vomiting, and abdominal pain.
    • Hematological Effects: Neutropenia and in rare cases, pancytopenia or agranulocytosis.
    • Hepatic Dysfunction: Elevated liver enzymes and potential hepatotoxicity with prolonged use.
    • Other Effects: Dizziness, headache, fever, and hair loss.

Contraindications and Precautions

  • Pregnancy: It is contraindicated due to potential teratogenic effects.
  • Liver Disease: Should be used cautiously in patients with hepatic impairment.
  • Blood Disorders: Regular monitoring of blood counts is advised for patients on prolonged therapy.

Drug Interactions

  • Albendazole’s metabolism and efficacy can be affected by:

    • CYP450 Enzymes: Interactions with drugs that induce or inhibit these enzymes can alter albendazole’s metabolism.
    • Antiepileptic Drugs: May reduce the efficacy of albendazole.
    • Grapefruit Juice: Can increase plasma concentrations of albendazole sulfoxide.

Special Considerations

  • Dosage in Children: Pediatric dosing may require adjustments based on weight and age.
  • Administration with Food: Taking albendazole with a fatty meal enhances its absorption and effectiveness.


Albendazole remains a critical component in the treatment of helminthic infections due to its broad-spectrum activity. Its effectiveness, coupled with a generally favorable safety profile, makes it a valuable tool in combating parasitic worms. However, its use must be carefully managed, considering its pharmacokinetic properties, potential adverse effects, and interactions with other medications.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always seek the advice of a healthcare provider with any questions regarding a medical condition.

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