[A version of this item appears in: Dementia: the Latest Evidence Newsletter (RWHT), Volume 1 Issue 12, July 2011].
Drugs prescribed commonly for conditions such as heart disease, depression and allergies are linked to a greater risk of death and risk of dementia (i.e. declining brain function). Approximately half of people over 65 are prescribed these drugs, and the level of risk appears to be greatest in patients taking multiple medications.
Researchers investigated medicines which influence the neurotransmitter acetylcholine as one of their side effects. Eighty drugs were rated for their “anticholinergic” activity and scored as “one” for a mild effect, “two” for moderate effect and “three” for severe effect. A combined score was calculated in 13,000 patients aged 65 or over, by simply adding together the scores for all the medicines taken.
Between 1991 and 1993, 20% of patients with a score of four or more died, whereas in people taking no anticholinergic drugs only 7% died. Patients with a score of five or more showed a 4% drop in ratings of brain function.
The drugs examined included:
Category One, Mild
- Codeine (painkiller).
- Warfarin (blood thinner).
- Timolol maleate (eye drops).
Category Three, Severe
- Piriton (antihistamine).
- Ditropan (incontinence drug).
- Seroxat (antidepressant).
These drugs did not necessarily cause death or reduced brain function, but the association is noteworthy.
Caution: People should not stop taking their medicines without first consulting their GPs.
Clinicians should review the medications taken by older patients, (whether prescribed or over the counter), and if possible avoid the prescription of multiple drugs with anticholinergic effects.
Further research into how anticholinergic drugs increase mortality and dementia risk is recommended. More recent research is desirable because recent practice and newer drugs have changed since the data used in this study was collected two decades ago.
Reductions in levels of the neurotransmitter acetylcholine are known to be implicated in dementia.
Gallagher, J. (2011). Common medicines for elderly linked to death. London: BBC News, June 24th 2011.
Fox, C. Richardson, K. [and] Maidment, I. [et al] (2011). Anticholinergic medication use and cognitive impairment in the older population: The Medical Research Council Cognitive Function and Ageing Study (CFAS). Journal of the American Geriatrics Society, June 24th 2011. (Click here to view the PubMed abstract).
For a quality review of this research, geared to the intelligent layman, see the following article from NHS Choices:
Study looks at medication risk for elderly. London: NHS Choices, June 24th 2011.