What are the side effects of albendazole?

Side Effects of Albendazole

Albendazole can cause serious side effects including bone marrow suppression, hepatotoxicity, and neurological symptoms, requiring careful monitoring especially during prolonged treatment courses. 1

Common Side Effects

• Gastrointestinal symptoms including abdominal pain (6% in hydatid disease), nausea (4-6%), and vomiting (4-6%) 1
• Headache (11% in neurocysticercosis patients) 1
• Dizziness and vertigo (approximately 1%) 1
• Fever (1% in hydatid disease) 1
• Reversible alopecia (2% in hydatid disease) 1

Serious Side Effects

Hepatotoxicity

• Elevated liver enzymes occur in approximately 16% of patients, especially during prolonged treatment 1, 2
• Most elevations resolve upon discontinuation of therapy 1
• Cases of acute liver failure and hepatitis have been reported 1, 3, 4
• Monitoring recommendations:
  • Check liver enzymes (transaminases) at the beginning of each 28-day treatment cycle 1
  • Monitor at least every 2 weeks during treatment 1
  • Consider discontinuing therapy if hepatic enzymes exceed twice the upper limit of normal 1

Hematologic Effects

• Bone marrow suppression, including leukopenia, granulocytopenia, pancytopenia, agranulocytosis, and thrombocytopenia 1
• Leukopenia occurs in up to 10% of patients 2
• Fatalities due to granulocytopenia or pancytopenia have been reported 1
• Patients with liver disease and hepatic echinococcosis are at increased risk for bone marrow suppression 1
• Monitoring recommendations:
  • Monitor blood counts at the beginning of each 28-day cycle 1
  • Continue monitoring every 2 weeks during therapy 1
  • Discontinue if clinically significant decreases in blood cell counts occur 1

Neurological Side Effects in Neurocysticercosis

• Treatment may cause exacerbation of neurological symptoms due to inflammatory reaction from parasite death 2
• Symptoms include headaches, seizures, increased intracranial pressure, and dizziness 2
• Between the second and fifth days of therapy, there is usually an exacerbation of neurological symptoms 2
• Preventive measures:
  • Concomitant steroid and anticonvulsant therapy is recommended 1
  • Oral or intravenous corticosteroids should be considered to prevent cerebral hypertensive episodes during the first week of treatment 1

Special Considerations

Pregnancy Risks

• Embryotoxicity and skeletal malformations were reported in animal studies 1
• Pregnancy testing is recommended for females of reproductive potential before starting therapy 1
• Females of reproductive potential should use effective contraception during treatment and for 3 days after the final dose 1

Risk Factors for Severe Side Effects

• Liver disease increases risk of both hepatotoxicity and bone marrow suppression 1
• Prolonged treatment courses (>14-28 days) increase risk of toxicity 5
• High doses may lead to neutropenia due to myelosuppression 5

Treatment Duration Considerations

• Short courses (1-3 days) for intestinal helminth infections generally have minimal side effects 2
• Longer courses for tissue parasites (neurocysticercosis, echinococcosis) require careful monitoring 2

Rare but Serious Side Effects

• Death related to albendazole-induced pancytopenia has been reported, particularly in patients with underlying liver disease 6
• Immune-mediated drug-induced liver injury has been reported, including in pediatric patients 7
• Hypersensitivity reactions, including rash and urticaria 1

Monitoring Recommendations

• For short courses (<14 days): routine monitoring may not be necessary 5
• For longer courses (>14 days): 2
  • Monitor complete blood counts at baseline and every 2 weeks
  • Monitor liver function tests at baseline and every 2 weeks
  • Discontinue therapy if significant abnormalities develop

Albendazole is generally well-tolerated for short-term use, but requires careful monitoring for longer treatment courses, particularly in patients with underlying liver disease or those receiving high doses 1, 5.