Albendazole dosage

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. 

The standard dosage, 25 mg/kg (maximum 1.5 g) twice daily, should be given after meals. Tablets should be chewed. For strongyloides infection, treatment is for 2 days. Cure rates are reportedly 93%. A course can be repeated in 1 week if indicated. In patients with hyperinfection syndrome, the standard dose is continued twice daily for 5-7 days. For cutaneous larva migrans, thiabendazole cream can be applied topically, or the oral drug can be given for 2 days (although albendazole is less toxic and therefore preferred). 

Albendazole is widely used in sheep and cattle for treating roundworms and flukes at oral dosages that range from 5 to 10 mg/kg bw. Albendazole and its sulfoxide metabolite exhibit teratogenic effects in animals. 

Netobimin is an albendazole prodrug intended for use in sheep and cattle. An oral dosage of 7.5 mg/kg bw is recommended for treatment of gastrointestinal infestations by roundworms and tapeworms, and 20 mg/kg bw for type II ostertag-iosis and adult flukes. Netobimin exhibits teratogenic effects in animals. 

Depending on the species, parbendazole, mebendazole, albendazole, oxfendazole, cambendazole, and febantel can be teratogenic in the parent form or indirectly from metabolite formation. Oxibendazole and fenbendazole in parent form are not teratogenic, although one of the metabolites of fenbendazole, a sulfoxide found in the milk of cows treated with fenbendazole, is teratogenic in the rat and sheep. Albendazole displays similar biotransformation pathways in cattle as it does in sheep, yet the bovine animal is refractory to its teratogenic effect at normal dosage rates. 

These pharmacokinetic interactions are established, and are likely to be clinically important when these anthelmintics are used to treat systemic worm infections. For these infections it may be necessary to increase the albendazole or mebendazole dosage in patients taking phenytoin, carbamazepine or phenobarbital. Monitor the outcome of concurrent use. The interactions are of no importance when these anthelmintics are used for intestinal worm infections (where their action is a local effect on the worms in the gut), which is the most common use of mebendazole in particular. 

There are numerous examples of medicinal products in which dissolution rate enhancing technologies are applied to increase the bioavailabiUty or absorption rate of an active substance. Cardiac glycosides should be given as micronised particles in a solid oral dosage form because otherwise their dissolution rate and hence their bioavaUability is too low. Piroxicam was shown to be absorbed faster when given as a cyclodextrin complex, which increases the dissolution rate. Similarly, the bioavailabiUty of albendazole as a cyclodextrin complex was increased compared to crystalline non-complexed albendazole, based on the same mechanism. And finally, the bioavailabiUty of amorphous chloramphenicol is higher than that of crystalline chloramphenicol. 

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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