Efficacy of tacrine and lecithin in mild to moderate Alzheimer's disease: double blind trial.

OBJECTIVE

To assess the efficacy of tacrine and lecithin in treating Alzheimer's disease over nine months.

DESIGN

Double blind randomised controlled trial.

SETTING

Outpatients clinic of university department of geriatric medicine.

SUBJECTS

53 subjects (26 women, 27 men) with probable Alzheimer's disease. 41 completed the dose finding phase and were randomised to treatment. 32 (14 tacrine, 18 placebo) completed nine months' treatment.

INTERVENTIONS

Lecithin and tacrine or lecithin and placebo for 36 weeks.

MAIN OUTCOME MEASURES

Scores on neuropsychological tests sensitive to deficits in the cholinergic system; mini-mental state score; behaviour change; mood; functional state; and stress in carers.

RESULTS

The tacrine and placebo groups were similar except that the tacrine group had a longer duration of disease (mean 5.4 v 2.5 years in placebo group; P = 0.003). Only 17 of the 32 patients could tolerate the maximum dose of tacrine (100 mg). No significant difference was found between the groups for any of the tests after nine months' treatment except for the digit backwards test, which is insensitive to cholinergic deficit. Analysis of subjects taking the maximum dose of tacrine and of subjects with mild dementia also found no differences.

CONCLUSIONS

Tacrine produces no clinically relevant improvement over 36 weeks at the doses tolerated by these patients.