Indication |
For the reduction of symptoms of intermittent claudication (pain in the legs that occurs with walking and disappears with rest). |
Pharmacodynamics |
Cilostazol is a quinolinone derivative indicated for the
reduction of symptoms of intermittent claudication, as indicated by an
increased walking distance. Intermittent claudication is pain in the
legs that occurs with walking and disappears with rest. The pain occurs
due to reduced blood flow to the legs. |
Mechanism of action |
Cilostazol and several of its metabolites are cyclic AMP (cAMP)
phosphodiesterase III inhibitors (PDE III inhibitors), inhibiting
phosphodiesterase activity and suppressing cAMP degradation with a
resultant increase in cAMP in platelets and blood vessels, leading to
inhibition of platelet aggregation and vasodilation. |
Absorption |
Cilostazol is absorbed after oral administration. A high fat meal increases absorption, with an approximately 90% increase in Cmax and a 25% increase in AUC. Absolute bioavailability is not known. |
Volume of distribution |
Not Available |
Protein binding |
95-98% |
Metabolism |
Hepatic. Cilostazol is extensively metabolized by hepatic
cytochrome P-450 enzymes, mainly 3A4, and, to a lesser extent, 2C19,
with metabolites largely excreted in urine. Two metabolites are active,
with one metabolite appearing to account for at least 50% of the
pharmacologic (PDE III inhibition) activity after administration of
cilostazol. |
Route of elimination |
Cilostazol is extensively metabolized by hepatic cytochrome P-450
enzymes, mainly 3A4, and, to a lesser extent, 2C19, with metabolites
largely excreted in urine. Cilostazol is eliminated predominately by
metabolism and subsequent urinary excretion of metabolites. The primary
route of elimination was via the urine (74%), with the remainder
excreted in feces (20%). No measurable amount of unchanged cilostazol
was excreted in the urine, and less than 2% of the dose was excreted as
3,4-dehydro-cilostazol.
About 30% of the dose was excreted in urine as
4'-trans-hydroxy-cilostazol. |
Half life |
11-13 hours. |
Clearance |
Not Available |
Toxicity |
Information on acute overdosage with cilostazol in humans is
limited. The signs and symptoms of an acute overdose can be anticipated
to be those of excessive pharmacologic effect: severe headache,
diarrhea, hypotension, tachycardia, and possibly cardiac arrhythmias.
The oral LD50 of cilostazol is >5.0 g/kg in mice and rats and >2.0 g/kg in dogs. |
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