Volume 176 - Issue 6
Pharmacological treatment of cognitive deficits in Alzheimer's disease
Authors: Henry Brodaty, Jane R Hecker, John A Snowdon and David J Ames
Med J Aust 2002; 176 (6): 297. || doi: 10.5694/j.1326-5377.2002.tb04419.x
Published online: 18 March 2002
Published online: 18 March 2002
In reply: We thank Lam for pointing out an error in the referencing in Box 3 of our article1 regarding the figures for adverse events for donepezil. The correct reference was number 48 in our list, not 49, and was to Rogers, Farlow, Doody et al,2 not to Rogers and Friedhoff,3 as suggested by Lam. The other references in Box 3 were given as 20, 21, 23 and 48, but should have been listed as 19, 20, 21 and 47, respectively.
Secondly, issue is taken with the rates of 17%, 17% and 10% for nausea, diarrhoea and vomiting, respectively, in people taking donepezil. We agree with the overall tenor of this letter that rates of side effects are generally lower in everyday practice.
The figures we quoted for adverse events are higher than the 11%, 10% and 5% cited in the Australian Product Information for donepezil,4 as the article by Rogers and colleagues2 refers to rates of adverse events experienced by those on the 10 mg dose, after a forced titration after only one week on 5 mg. We presented data for adverse events at the 10 mg dose, as this was the dose recommended for donepezil given the findings of greater benefit on the higher dose. The Australian Product Information does not indicate whether the rates of adverse events refer to the 5 mg or 10 mg dose.
Usual clinical practice, which is to start with 5 mg daily and increase to 10 mg after 4–6 weeks, results in fewer adverse events. The figures of 11.3% for nausea, 7% for diarrhoea and less than 5% for vomiting presented in the Nordic study,5 in which over 80% of patients were taking 10 mg of donepezil daily, with a more flexible titration schedule, appear to be more realistic.
References
- Brodaty H, Ames D, Boundy KL, et al. Pharmacological treatment of cognitive deficits in Alzheimer's disease [review]. Med J Aust 2001; 175: 324-329.
- Rogers SL, Farlow MR, Doody RS, et al. A 24-week, double-blind, placebo-controlled trial of donepezil in patients with Alzheimer's disease. Neurology 1998; 50: 136-145. i1146943
- Rogers S, Friedhoff L. Long-term efficacy and safety of donepezil in the treatment of Alzheimer's disease: an interim analysis of the results of a US multicentre open label extension study. Eur Neuropsychopharmacol 1998; 8: 67-75. i1146945
- Australian-approved Product Information for Donepezil. Sydney: Pfizer Pty Limited, 10 December 2001.
- Winblad B, Engedal MD, Soininen H, et al. A 1-year, randomized, placebo-controlled study of donepezil in patients with mild to moderate AD. Neurology 2001; 57: 489-495. i1146950