The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.
Letter to the Editor
Editor, – I suggest that the article 'Anticholinergic drugs for overactive bladder' (Aust Prescr 2006;29:22-4) gives insufficient prominence to the inevitable occurrence of cognitive impairment from antimuscarinic drugs. There is overwhelming evidence that all antimuscarinic drugs cause cognitive impairment even in healthy people,1 and this is frequently clinically significant in older people.234 Any possibility that a treatment will worsen patients' mental function has profound implications and must be regarded with the utmost seriousness.
The therapeutic margin is narrow, or non-existent, and individual variations in blood concentrations and response mean that in practice it will be difficult to achieve a consistently favourable therapeutic effect. Many other commonly used drugs also have antimuscarinic effects so interactions are likely to be frequent. I suggest the average practitioner has insufficient knowledge of these interactions to successfully avoid them.5
Pioneer Valley Private Hospital
North Mackay, Qld
- Robbins TW, Semple J, Kumar R, Truman MI, Shorter J, Ferraro A, et al. Effects of scopolamine on delayed-matching-to-sample and paired associates tests of visual memory and learning in human subjects: comparison with diazepam and implications for dementia. Psychopharmacology (Berl) 1997;134:95-106.
- Ancelin ML, Artero S, Portet F, Dupuy AM, Touchon J, Ritchie K. Non-degenerative mild cognitive impairment in elderly people and use of anticholinergic drugs: longitudinal cohort study. BMJ 2006;332:455-9.
- Lu CJ, Tune LE. Chronic exposure to anticholinergic medications adversely affects the course of Alzheimer disease. Am J Geriatr Psychiatry 2003;11:458-61.
- Tune LE, Egeli S. Acetylcholine and delirium. Dement Geriatr Cogn Disord 1999;10:342-4.
- Guay DR. Clinical pharmacokinetics of drugs used to treat urge incontinence. Clin Pharmacokinet 2003;42:1243-85.