Marras C et al. – This study found no specific beneficial effect of treatment with brain penetrant dihydropyridines on delaying parkinsonism progression milestones. Dihydropyridine calcium channel blockers are unlikely to have a clinically significant effect on the course of parkinsonism, particularly Parkinson's disease, in the doses used to treat hypertension.

• Data were obtained from Ontario's health care administrative databases.
• Within a cohort of hypertensive individuals over the age of 65 who developed parkinsonism, the authors examined the effect of the length of exposure to less brain penetrant dihydropyridines (amlodipine) and more brain penetrant dihydropyridines (e.g. nifedipine, felodipine) on parkinsonism milestones as measured by time to requiring drug treatment for parkinsonism, nursing home admission and death.

• Among 4733 hypertensive individuals with parkinsonism, longer treatment with any dihydropyridine was associated with a decreased risk of each of the three outcomes.
• There was no difference, however, between amlodipine (adjusted HRs 0.46 (0.42, 0.50) for initiation of drug treatment, 0.68 (0.63, 0.73) for application for nursing home admission and 0.75 (0.70, 0.80) for death) and non-amlodipine dihydropyridines (adjusted HRs 0.45 (0.39, 0.53), 0.74 (0.67, 0.81) and 0.74 (0.64, 0.85) for the three milestones respectively.