albendazole

Action and Spectrum

Actions and Spectrum: 

albendazole, which is an anthelmintic medication used to treat parasitic infections caused by various worms, including roundworms, hookworms, and tapeworms. The action and spectrum of albendazole are as follows: 

• Action: albendazole works by inhibiting microtubule formation in the parasite, ultimately leading to the parasite’s immobilization and death. This action prevents the parasites from reproducing and spreading in the body. 
• Spectrum: albendazole is effective against a wide range of parasites, including: 

Intestinal parasites: albendazole is effective against roundworms, hookworms, whipworms, and pinworms. 

Tissue parasites: albendazole can also treat tissue parasites like tapeworms and flukes. 

albendazole is ineffective against all types of parasites, and its efficacy may vary depending on the parasite species and the infection’s severity. 

Drug Interaction

Adverse Reaction

Frequency defined 

>10% 

Neurocysticercosis  

Headache (11%) 

Abnormal LFT (<1%) 

Hydatid disease 

Headache (1.3%) 

Abnormal LFT (15.6%) 

1-10% 

Neurocysticercosis 

Nausea 

vomiting 

Dizziness 

Vertigo 

Increased intracranial pressure 

Meningeal signs 

Alopecia (reversible) 

Hydatid disease 

Abdominal pain 

Alopecia (reversible) 

Dizziness 

vertigo 

Nausea 

vomiting 

Fever 

<1% 

Hepatitis 

Rash 

Bone marrow suppression 

Agranulocytosis 

Granulocytopenia 

Aplastic anemia 

Acute renal failure 

Urticaria 

Pancytopenia 

Acute liver failure 

Thrombocytopenia 

Black Box Warning

Black Box Warning: 

albendazole has a black box warning for its potential to cause hepatotoxicity (liver damage) and bone marrow suppression.  

The black box warning for albendazole states that the drug may cause severe liver damage, including hepatitis, jaundice, and liver failure.  

albendazole can also cause bone marrow suppression, which may result in decreased white blood cell count, anemia, and thrombocytopenia. Patients should be monitored for signs of bone marrow suppression during treatment. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

albendazole is generally contraindicated in patients with known hypersensitivity or allergy to the medication or its components. In addition, there are several other conditions in which the use of albendazole is contraindicated or should be used with caution, including: 

• Pregnancy: albendazole may harm the fetus and should not be used during pregnancy unless the potential benefits outweigh the risks. 
• Breastfeeding: albendazole may be excreted in breast milk and harm a nursing infant. Breastfeeding should be avoided during treatment with albendazole. 
• Liver disease: albendazole can cause hepatotoxicity (liver damage) and should be used cautiously in patients with pre-existing liver disease. 
• Blood disorders: albendazole can cause bone marrow suppression, which may result in decreased white blood cell count, anemia, and thrombocytopenia. It should be used cautiously in patients with blood disorders or those taking medications that may affect blood cell counts. 
• Children: The safety and effectiveness of albendazole in children under the age of 6 years have yet to be established. 
• Eye disease: albendazole has been associated with retinal toxicity, and caution should be used in patients with a history of eye disease. 
• Renal impairment: albendazole is primarily eliminated through the liver and may require dose adjustment in patients with renal impairment. 

Caution 

• Drug interactions: albendazole may interact with other medications, including cimetidine and dexamethasone, and may increase the risk of side effects. Patients should inform their healthcare providers of all medications they take before using albendazole. 
• Neurocysticercosis: albendazole can cause inflammation and swelling of the brain in patients with neurocysticercosis (a parasitic infection of the brain). Patients with this condition should be closely monitored during treatment with albendazole. 
• Overdose: In case of overdose, symptoms such as headache, nausea, vomiting, abdominal pain, and seizures may occur. 
• Hypersensitivity reactions: albendazole can cause hypersensitivity reactions in some patients, including skin rash, itching, and hives. If any of these symptoms occur, discontinue use and seek medical attention. 
• Driving or operating machinery: albendazole may cause dizziness or drowsiness, impairing the ability to drive or operate machinery. Patients should avoid these activities until they know how albendazole affects them. 

Pregnancy / Lactation

Pregnancy consideration:  

AU TGA pregnancy category: D
US FDA pregnancy category: C 

Lactation:   

Excreted into human milk: Yes. 

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies do not show risk to the fetus in the first/later trimester.        
• Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women        
• Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.       
• Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.        
• Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.        
• Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

albendazole is a benzimidazole anthelmintic drug that exerts its pharmacological effects by binding to the β-tubulin protein of helminths (parasitic worms). This leads to the inhibition of microtubule polymerization and function, ultimately resulting in impaired glucose uptake, energy depletion, and disintegration of the parasites. 

albendazole has a broad-spectrum activity against different types of helminths, including tapeworms, roundworms, and flukes. It is highly lipophilic, rapidly absorbed after oral administration, with peak plasma concentrations achieved within 2-5 hours. The drug is metabolized in the liver, primarily by the cytochrome P450 (CYP450) enzyme system, and is excreted in the urine and feces as inactive metabolites. 

Pharmacodynamics: 

Mechanism of action: The action of this substance involves the degeneration of cytoplasmic microtubules in the intestinal and tegmental cells of intestinal helminths. 

Pharmacokinetics: 

Absorption 

albendazole has poor water solubility and limited bioavailability due to its low solubility in the gastrointestinal tract. However, albendazole’s bioavailability is increased when taken with a high-fat meal. After oral administration, albendazole is rapidly absorbed from the gastrointestinal tract and reaches peak plasma concentrations within 2-5 hours. 

Distribution 

albendazole is highly lipophilic and extensively distributed in body tissues. The drug has  volume of distribution of about 2 to 4 L/kg, indicating that it penetrates well into tissues. albendazole has been detected in cerebrospinal fluid, liver, lungs, cystic fluid, and hydatid cysts. 

Metabolism 

albendazole is metabolized primarily by the liver through oxidation and reduction reactions. The cytochrome P450 (CYP450) enzyme system plays a significant role in the metabolism of albendazole. The major metabolite of albendazole is albendazole sulfoxide, which is pharmacologically active and responsible for the drug’s anthelmintic activity. 

Elimination and Excretion 

albendazole and its metabolites are eliminated from the body primarily through the biliary route. Less than 1% of the drug is excreted unchanged in the urine. The elimination half-life of albendazole is 8-12 hours, which allows for once-daily dosing in most cases.  

Adminstartion

Administration: 

Oral administration 

albendazole is usually administered orally, with or without food, depending on the specific instructions provided by the healthcare provider. The medication comes in the form of tablets or capsules, and the dosing and duration of treatment may vary depending on the condition. 

For example, in treating intestinal parasites, the recommended adult albendazole dose is 400 mg once daily for three consecutive days. The dose may be higher for the treatment of neurocysticercosis and given for a more extended period. 

It is crucial to take albendazole precisely as prescribed by the healthcare provider and complete the entire treatment course, even if symptoms improve. Skipping doses or stopping treatment early may result in incomplete treatment and increase drug resistance risk. 

If you have difficulty swallowing the tablets or capsules, they may be crushed and mixed with food or liquid. However, it is essential to check with the healthcare provider or pharmacist before altering the form of the medication. 

If a dose is missed, it is recommended to take it as soon as possible. However, if the next scheduled dose is missed, it should be skipped and the following dose should be taken at the appropriate time. It is important to avoid taking a double dose of the medication to compensate for the missed dose.

Patient Information Leaflet

Patient information leaflet 

Generic Name: albendazole 

Pronounced: [ al-BEN-da-zole ] 

Why do we use albendazole? 

albendazole is an anthelmintic medication used to treat a variety of parasitic infections, including: 

• Intestinal parasites: albendazole treats infections caused by intestinal parasites such as tapeworm, roundworm, and hookworm. 
• Neurocysticercosis: albendazole is also used to treat neurocysticercosis, a parasitic brain infection caused by the pork tapeworm’s larvae. 
• Hydatid disease: albendazole is used to treat hydatid disease, a parasitic infection caused by the larval stage of the dog tapeworm. 
• Strongyloidiasis: albendazole can treat strongyloidiasis, a parasitic infection caused by the roundworm Strongyloides stercoralis. 
• Cutaneous larva migrans: albendazole may also be used to treat cutaneous larva migrans, a skin infection caused by the larvae of dog and cat hookworms. 

albendazole works by interfering with the parasite’s ability to absorb glucose, which is necessary for survival. This leads to the death of the parasite and eventual elimination from the body.