Acute effect of ketanserin on the leg perfusion assessed by Doppler pressure measurements and 201Tl scintigraphy in patients with intermittent claudication.

Ketanserin, a serotonin2-receptor blocker, was administered intravenously (10 mg) to 10 patients suffering from unilateral intermittent claudication in a double-blind, placebo-controlled, cross-over design. The acute effect of the drug was studied by doppler systolic pressure (SP) measurements at arm and ankle at rest (10 min after injection) and after exercise, and by radioactive thallium (201Tl) stress scintigraphy of the legs. Resting ankle-arm SP ratio was significantly higher after ketanserin compared with placebo. This was due to a lowered systemic SP with unchanged ankle SP. This difference was not seen after exercise. In addition, the drug did not influence significantly the postexercise accumulation of thallium in the distal leg on the affected or healthy side, although the difference between these two became significantly larger in favour of the healthy leg. Thus, acute administration of ketanserin improves peripheral hemodynamics in claudicating patients at rest, but muscle exercise abolishes this response. A beneficial effect of ketanserin in intermittent claudication cannot be anticipated from these results.