[Donepezil as treatment of Charles Bonnet syndrome].

The treatment of the Charles Bonnet syndrome (CBS) can become extremely complex and must include all areas related to its etiopathogeny. Some aspects of the comprehensive treatment of the process include providing adequate information to the patient and his family, improving their quality of life, treating the cause whenever possible or the secondary anxiety syndrome.1,2 In what concerns the medical treatment there is a broad range of options which are efficient at different levels of the CBS pathogeny and the histological and biochemical changes that occur in differentiated synopsis, a key element in the pathogenesis of the process. The biochemical changes in the central nervous system such as acetylcholine reduction in the thalamus, are the basis of the treatment with donezepil hydrochloride,2,3 an inhibitor used in the treatment of slight to moderately severe Alzheimer disease (AD) found in the market under the brand name Aricept® (Pfizer S.A., Alcobendas, Madrid, Spain). Donezepil hydrochloride is a selective and reversible inhibitor of acetylcholinesterase, the cholinesterase which predominates in the brain. This inhibition can reach up to 77.3% in Alzheimer patients treated with 10 mg doses, with an efficacy ranging between 18% and 22%. However, the effects of this medication on the progression of the disease are not known.3 In CBS as well as in AD, treatment consists in an initial dose of 5 mg per day in a single take, which can be increased up to a maximum of 10 mg per day one month after beginning the treatment and after assessing patient response. Donezepil hydrochloride is not recommended for use in children (in exceptional CBS cases) and is contraindicated in pregnancy. However, it can be used in patients with moderate kidney or liver insufficiency. Table 1 lists the warnings, special precautions for use and adverse reactions of the drug, and Table 2 summarizes the interactions with other drugs. Paradoxically,