Clinical Practice with Antidementia Drugs in a Geriatric Clinic
Thipparut Rungsanpanya MD*, Weerasak Muangpaisan MD*, Roongnirand Praditsuwan MD*
Affiliation : * Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Background : Cholinesterase inhibitors and N-methyl-D-aspartate antagonist have been used increasingly for patients with
dementia. However, these products are relatively costly and have been linked to many adverse events. Only a few surveys
of prescribing patterns of drugs for dementia have been conducted in developing countries, while the proportion of dementia
patients is expected to become higher in these regions. We aim to evaluate the utilization patterns, adverse events, and cost
of antidementia drugs in a geriatric clinic at Siriraj hospital.
Material and Method: Data was obtained from the medical records of dementia patients who were newly diagnosed between
January 2007 and December 2009 in the Geriatric clinic, Siriraj hospital, Bangkok. The diagnosis was based on DSM-IV
(Diagnostic and Statistical Manual of Mental Disorders-IV) criteria.
Results : Ninety-six elderly patients were diagnosed with dementia during the studied period. Eighty patients (83.3%) with
the average age of 80.6 (SD = 7) years received antidementia drugs. Donepezil was the most frequently prescribed
drug (70%), followed by rivastigmine (22.5%). Concomitant use of interacting drugs was noted in 41.3% of patients.
The average prescribed daily dose of rivastigmine, galantamine and memantine were lower than their effective defi ned
daily dose. The highest average cost per year was galantamine (60,020.5 baht/year) and the lowest one was memantine
(45,857.7 baht/year). Among cholinesterase inhibitors receivers, 43.5% had at least one adverse event. Thirty-seven percent
of these were gastrointestinal side effects. Only 12.5% of memantine-receivers developed adverse events. One-year drug
discontinuation rates were 26.1% and 12.5% in cholinesterase inhibitor and memantine groups, respectively. From
multivariate logistic regression analysis, the only factor associated with adverse drug events was the presence of behavioral
and psychological symptoms.
Conclusion : The majority of dementia patients in our study were prescribed antidementia drugs. Half of them developed
adverse events, but one-year drug discontinuation was relatively low. The average daily doses were lower than recommended
doses. Future prospective studies should be performed to determine the cost-effectiveness and establish evidence-based
practice guideline for management of dementia patients.
Keywords : Adverse drug event, Cholinesterase inhibitor, Dementia, Geriatric, Prescribing pattern
