Indications
Cilostazol is primarily indicated for the relief of symptoms associated with intermittent claudication, which is characterized by pain in the legs that arises during walking and subsides with rest. This condition results from reduced blood flow to the lower extremities.
Pharmacodynamics
The therapeutic effect of Cilostazol in treating intermittent claudication is evidenced by an increase in walking distance. By improving blood flow, Cilostazol helps alleviate leg pain that occurs due to this condition.
Absorption
Following oral administration, Cilostazol is absorbed into the system. The presence of a high-fat meal significantly enhances its absorption, with a noted increase of approximately 90% in the peak plasma concentration (Cmax) and a 25% rise in the area under the curve (AUC). The absolute bioavailability of Cilostazol, however, remains undetermined.
Metabolism
Cilostazol undergoes extensive hepatic metabolism, primarily involving the cytochrome P-450 enzymes 3A4 and, to a lesser extent, 2C19. Its metabolites are largely excreted via urine. Among these metabolites, two are active, with one responsible for approximately 50% of Cilostazol's pharmacologic effect, particularly its phosphodiesterase type III (PDE III) inhibitory action.
Mechanism of Action
Cilostazol functions as a selective inhibitor of cyclic AMP (cAMP) phosphodiesterase III, effectively reducing phosphodiesterase activity and preventing the degradation of cAMP. This mechanism results in elevated cAMP levels within platelets and blood vessels, thereby promoting the inhibition of platelet aggregation and facilitating vasodilation. Through these actions, Cilostazol enhances vascular health and supports optimal blood flow.
