Pharmacological Treatments of Alzheimer's Disease: Current Medication, Future Trends

Alzheimer’s disease (AD) that is identified by progressive cognitive deficit and behavioral disturbances (BD) are the most common form of dementia. As the population is aging, patients with AD are becoming a serious burden for societies. In this study, current medication for cognitive deficit and behavioral disturbances are reviewed. Also the new treatment strategies for cognitive dysfunction and behavioral disturbances are surveyed. The method employed in this researh was a systematic bibliographic review, in which only the double-blind placebo-controlled studies or the clinically detailed enough open-labeled studies using validated scales were retained. The efficacy of cholinesterase inhibitors (Tacrine, Rivastigmine, Donapezil and Galantamine) has been demonstrated in several double blind placebo controlled clinical trials. They have shown a mild efficacy in mild to moderate AD. Memantine, a NMDA antagonist is the only drug that has demonstrated mild efficacy in moderate to severe AD in controlled clinical trial. Clinical trials surveying the efficacy of active and passive immunization against B amyloid protoin has halted due to serious adverse events. Studies of inducing neurogenesis in brain of AD patients are preliminary. Antipsychotics have shown efficacy for controlling BD of AD patients but they are associated with adverse events. Except for carbamazepine, there is not enough evidence for other anticanvulsants to be effective for behavioral disturbances of AD patients. A controlled clinical trial and some open studies have shown the efficacy of citalopram for BD. Further studies are needed to confirm the efficacy of other medications like trazadon, buspiron and beta blockers for BD. Cholinesterase inhibitors have demonstrated disappointing results. Memantine is only mildly effective for cognitive deficit. To date, no amyloid-modifying therapy has yet been successful in phase 3 clinical trials. Further studies are needed for more effective and safe cognitive enhancing agents. Antipsychotics, the usually employed medication for behavioral disturbances are associated with adverse events so looking for safer and effective medication in this regard is necessary.