MECHANISM: Decrease in arteriolar resistance via vasodilation. This arterial vasodilation goes unmatched by the venous circulation, which CCB do not effect. This is a disproportionate change in resistance increasing hydrostatic pressure in the capillary circulation and causing fluid to shift into the interstitium. Hence, edema!
Domenic A. Sica. Calcium channel blocker-related periperal edema: can it be resolved? J Clin Hypertens (Greenwich) 2003 Jul-Aug; 5(4): 291-4, 297.