Albendazole anthelmintic for Cestode/Tapeworm Infections (Neurocysticercosis, Hydatid Disease)

Albendazole anthelmintic for Cestode/Tapeworm Infections (Neurocysticercosis, Hydatid Disease)

Albendazole ( C12H15N3O2S ) is used in the treatment of tissue infections caused by the larval forms of certain cestodes (tapeworms) including neurocysticercosis caused by ysticercus cellulosae, the larval form of Taenia solium (pork tapeworm). Albendazole also is used for the treatment of hydatid disease caused by the larval form of Echinococcus granulosus (dog tapeworm). Other anthelmintics (usually praziquantel or nitazoxanide) are used for the treatment of intestinal infections caused by adult forms of cestodes.

Neurocysticercosis
Albendazole is used for the treatment of parenchymal neurocysticercosis resulting from active lesions caused by Cysticercus cellulosae, the larval form of Taenia solium (pork tapeworm), preferably in combination with corticosteroids. Symptoms commonly associated with neurocysticercosis include headaches, seizures, or other CNS effects thought to result from expanding active cysticercal lesions or edema surrounding individual degenerating cysts in brain parenchyma. Therefore, important measures of response to antineurocysticercal therapy include resolution of CNS symptoms and radiologic response.

The manufacturer states that safety and efficacy of albendazole in patients with neurocysticercosis caused by T. solium was demonstrated by analysis of 3 sets of data, including a compilation of data from published reports of albendazole use in neurocysticercosis, data from US compassionate use patients, and data from one limited clinical study. In studies of patients with susceptible neurocysticercal lesions (i.e., nonenhancing cysts with no surrounding edema on contrast-enhanced computerized tomography) receiving albendazole, the number of cysts was reduced by 74-88%, and resolution of all active cysts occurred in 40-70% of patients. Combining two of the data sets (the report compilation and the US compassionate use data), the manufacturer states that about 41% of patients experienced a cure (no symptoms of neurocysticercosis), about 50% of patients were considered to be improved, and 9% experienced no change. Corticosteroids are used concomitantly to reduce the frequency and severity of adverse nervous system effects (CSF reaction syndrome), associated with albendazole therapy for neurocysticercosis. Anticonvulsant therapy also may be necessary.

Use of anthelmintics (albendazole or praziquantel) in the treatment of cysticercosis is controversial since efficacy has not been proven in controlled studies. Initial treatment of parenchymal disease with seizures should focus on symptomatic treatment with anticonvulsants. Obstructive hydrocephalus is treated with surgical removal of the obstructing cyst or CSF diversion and prednisone; arachnoiditis, vasculitis, or cerebral edema is treated with corticosteroids (prednisone or dexamethasone) used in conjunction with albendazole or praziquantel. Even when corticosteroids are used, any cysticercocidal drug may cause irreparable damage when used to treat ocular or spinal cysts, and ophthalmic exams should be performed before treatment to rule out intraocular cysts

Hydatid Disease
Albendazole is used for the treatment of cystic hydatid disease (unilocular hydatid disease) of the liver, lung, and peritoneum, caused by the larval form of the dog tapeworm (Echinococcus granulosus). Surgery is considered to be the treatment of choice for hydatid disease, when medically feasible, but perioperative administration of an anthelmintic drug (e.g., albendazole, mebendazole, praziquantel) may be indicated in patients undergoing surgical removal of cysts to minimize the risk of intraoperative dissemination of daughter cysts. Percutaneous drainage with ultrasound guidance plus albendazole therapy has been effective for the management of hepatic hydatid cyst disease.

Albendazole is absorbed to a greater extent, and achieves higher plasma concentrations (as its active metabolite) than mebendazole, and some clinicians consider albendazole to be a drug of choice for treatment of hydatid cyst disease caused by E. granulosus. Risks associated with surgery include operative morbidity, cyst recurrence, and anaphylaxis or dissemination of infection resulting from spillage of fluid from the cysts. Preoperative administration of albendazole may inactivate protoscolices and minimize the possibility of recurring cysts, and postoperative treatment with the drug may prevent secondary dissemination of the cestode that can occur after spontaneous or operative rupture and spillage of cyst contents. Optimal cysticidal effect of albendazole is achieved preoperatively or postoperatively when the drug is administered in three 28-day courses of therapy. Also, some clinicians have recommended administration of albendazole in patients with inoperable, widespread, or numerous E. granulosus cysts, or in patients with complex medical problems who are not eligible for surgery.

The manufacturer states that because of the low incidence of hydatid disease, safety and efficacy of albendazole in patients with hydatid disease caused by E. granulosus was demonstrated by combining data from accumulated clinical reports in small series of patients. Four sets of data were considered, including data from European compassionate use patients, an analysis of data from published studies, data from Australian compassionate use patients (not evaluable), and data from US compassionate use patients. About 80-90% of patients receiving albendazole in three 28-day cycles had noninfectious cyst contents. About 30-31% of evaluable patients with hydatid disease receiving albendazole experienced a clinical cure (i.e., disappearance of cysts), and improvement (i.e., a reduction in cyst diameter of at least 25%) was observed in about 40-42% of evaluable patients. About 24% of patients receiving albendazole experienced no change or were considered to be worse.

Although albendazole has been used to treat alveolar hydatid disease, another form of hydatid cyst disease caused by Echinococcus multilocularis, surgical excision of the larval mass is the recommended and only reliable treatment for this infection. Continuous albendazole or mebendazole therapy reportedly has been associated with clinical improvement in nonresectable cases, but the manufacturer states that efficacy of albendazole in the treatment of alveolar hydatid disease caused by E. multilocularis has not been clearly demonstrated in clinical studies.