Albendazole bioavailability

Nagy J, Schipper HG, Koopmans RP, Butter JJ, Van Boxtel CJ, Kager PA. Effect of grapefruit juice or cimetidine coadministration on albendazole bioavailability. Am J Trop Med Hyg 2002 66(3) 260-263. 

Albendazole is now the preferred drug, but when it is not appropriate or available, praziquantel has similar efficacy. Indications for praziquantel are similar to those for albendazole. The praziquantel dosage is 100 mg/kg/d in three divided doses for 1 day, then 50 mg/kg/d to complete a 2- to 4-week course. Clinical responses to therapy vary from dramatic improvements of seizures and other neurologic findings to no response and even progression of the disease. Praziquantel —but not albendazole—has diminished bioavailability when taken concurrently with a corticosteroid. Recommendations on use of both antihelminthics and corticosteroids in neurocysticercosis vary. 

Kohri, N., Y. Yamayoshi, H. Xin, K. Iseki, N. Sato, S. Todo, and K. Miyazaki. 1999. Improving the oral bioavailability of albendazole in rabbits by the solid dispersion techniiiG arm Pharmacol 51 159-164. 

Merino, G., Alvarez, A.L, Redondo, P.A., Garcia, J.L., Larrode, O.M., and Prieto, J.G. (1999) Bioavailability of albendazole sulphoxide after netobimin administration in sheep effects of fenbendazole coadministration. Research in Veterinary Science, 66 (3), 281—283. 

Inducers of hepatic CYPs such as carbamazepine and phenobarbital reduce the bioavaUabihty of praziquantel. Dexamethasone reduces the bioavailability of praziquantel, but the mechanism is not understood. Under certain conditions, praziquantel may increase the bioavailability of albendazole. 

Interestingly, the drug s bioavailability gets enhanced in the presence of fat e.g., the presence of 40g fat helps to enhance the plasma concentrations of albendazole to nearly five fold in comparison to that observed in the fasting subjects . 

Mebendazole, ttabendazole and albendazole aie benzimidazoles given orally. They have a wide range of action, especially against intestinal nematodes. Mebendazole and albendazole have few side-effects, probably because they have low systemic bioavailability. 

Levamisole may markedly decrease the bioavailability of albendazole sulfoxide, but albendazole has no clinically significant effects on levamisole pharmacokinetics. 

Albendazole does not alter the bioavailability of praziqoanteL Praziquantel markedly increases the bioavailability of albendazole sulfoxide in fasted subjects, but much less so when albendazole is given with a meal, as recommended. None of these changes appears to have adverse consequences. 

Garefa-Rodriguez, J. J., Torrado, J., and Bolas, F. (2001). Improving bioavailability and anthelmintic activity of albendazole by preparing albendazole-cyclodextrin complexes. Parasite, 8, S188-S190. 

Mukherjee, T., Plakogiannis, F.M., 2010. Development and oral bioavailability assessment of a supersaturated self-microemulsifying drug delivery system (SMEDDS) of albendazole. J. Pharm. Pharmacol. 62, 1112—1120. 

An active substance, although initially released from its dosage form (and dissolved), may become unavailable for absorption due to reactimis with other medicines or food components [4]. An example is the formation of insoluble complexes of tetracycline with calcium or aluminium ions from antacids or milk products. Interaction (chelation or binding) with iron ions leads to a reduced absorption for a variety of active substances such as doxycycline, penicillamine, methyldopa and ciprofloxacin. The absorption of active substances showing pH-dependent dissolution behaviour may be influenced by medicines that influence the gastric pH, such as H2-antagonists, proton pump inhibitors and antacids. Antimycotic active substances such as ketoconazole or itraconazole dissolve better in acidic fluids. Therefore their bioavailability may be increased by the concomitant use of an acidic drink like cola, whereas the concomitant use of antacids or proton pump inhibitors is likely to reduce the bioavailability. Concomitant use of milk may increase the dissolution of acidic active substances, whereas fats from food may increase the bioavailability of lipophilic active substances like albendazole and griseofulvin. 

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