Isradipine Versus Placebo in Early Parkinson Disease: A Randomized Trial

The Parkinson Study Group STEADY-PD III Investigators


Studies suggest that dihydropyridine calcium-channel blockers may be associated with reduced risk for Parkinson disease (PD).


To assess the effect of isradipine, a dihydropyridine calcium-channel blocker, on the rate of clinical progression of PD.


336 patients were randomly assigned (mean age, 62 years [SD, 9]; 68% men; disease duration, 0.9 year [SD, 0.7]; mean UPDRS part I to III score, 23.1 [SD, 8.6]); 95% of patients completed the study. Adjusted least-squares mean changes in total UPDRS score in the antiparkinson medication ON state over 36 months for isradipine and placebo recipients were 2.99 (95% CI, 0.95 to 5.03) points versus 3.26 (CI, 1.25 to 5.26) points, respectively, with a treatment effect of −0.27 (CI, −3.02 to 2.48) point (P = 0.85). Statistical adjustment for antiparkinson medication use did not change the findings. Secondary outcomes showed no effect of isradipine treatment. The most common adverse effects of isradipine were edema and dizziness.


Long-term treatment with immediate-release isradipine did not slow the clinical progression of early-stage PD.



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