Long-term treatment with tacrine (THA) in Alzheimer's disease--evaluation of neuropsychological data.

Long-term effects of tacrine (THA) on cognitive functions of very mild AD patients were studied. The stability of possible positive changes following prolonged treatment and the effect of increased dose was also studied. Three patients were treated with tacrine (80 mg/day) and the effect on cognitive functions was measured with a neuropsychological test battery. Two of the patients (Pats 1 and 4) showed clear positive changes in all parameters measured. The third patient (Pat 5) did not show as clear positive responses. The effect of the initial treatment dose diminished over time. After raising the dose two of the patients showed improvement in cognitive tests reaching their initial level of performance or even better in most of the tests. This positive effect was not as clear in patient 5. After 13 months of tacrine all patients still showed positive changes in some of the tests. Compared to a hypothetical progression curve for untreated AD patients the patients treated with tacrine seemed to have slower progression. In conclusion, it seems that long-term positive effects on cognitive functions of AD patients can be reached with tacrine and it seems to be possible to slow down the progression of the disease. However, to reach long-term positive effects increasing doses seem to be needed. AD patients seem to differ in their response to tacrine.