Last week I blogged about a study that showed how some dementia drugs may help reduce the progression of the disease and delay admission to care homes for people with the condition.

This new systematic review carried out by a research team from Harvard Medical School investigates the potential side effects of two dementia drugs:

1. Memantine
2. Cholinesterase inhibitors

The outcomes investigated are:

• Falls
• Syncope (Temporary loss of consciousness caused by a fall in blood pressure)
• Fracture
• Accidental injury

Researchers carried out a systematic search on a range of databases to find randomised controlled trials and extension studies of cholinesterase inhibitors and memantine that reported falls, syncope, and related events in cognitively impaired older adults living in the community and in nursing homes. They found 54 studies to include in their analysis.

The results showed that, when compared with placebo:

• Memantine use was associated with fewer fractures (OR=0.21, 95% CI=0.05-0.85)
• Memantine use was associated with no effect on falls (OR=0.92, 95% CI=0.72-1.18), syncope (OR=1.04, 95% CI=0.35-3.04) and accidental injury (OR=0.80, 95% CI=0.56-1.12).
• Use of cholinesterase inhibitors was associated with greater risk of syncope (odds ratio (OR)=1.53, 95% confidence interval (CI)=1.02-2.30)
• Use of cholinesterase inhibitors was associated with no effect on falls (OR=0.88, 95% CI=0.74-1.04), fracture (OR=1.39, 95% CI=0.75-2.56) and accidental injury (OR=1.13, 95% CI=0.87-1.45)
• There was no differential effect according to type and severity of cognitive impairment, residential status, or length of follow-up, although because of underreporting and small number of events, a potential benefit or risk cannot be excluded.

The authors concluded that:

Memantine may have a favorable effect on fracture, with no effects on other events. More research is needed to confirm the reduction in fractures observed for memantine.

Cholinesterase inhibitors may increase the risk of syncope, with no effects on falls, fracture, or accidental injury in cognitively impaired older adults.

Kim DH, Brown RT, Ding EL, Kiel DP, Berry SD. Dementia medications and risk of falls, syncope, and related adverse events: meta-analysis of randomized controlled trials. J Am Geriatr Soc. 2011 Jun;59(6):1019-31. doi: 10.1111/j.1532-5415.2011.03450.x. Epub 2011 Jun 7. [PubMed abstract]