Cilostazol

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.

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.

Description

Cilostazol is a platelet aggregation inhibitor with cerebral vasodilating activity, indicated for use in stroke and myocardial infarction. In patients with cerebral thrombosis, transient ischemia and cerebral arteriosclerosis, cilostazol significantly inhibits ADP-, collagenand epinephrine-induced platelet aggregation. Side effects include headache and tachycardia.

Chemical properties

Colourless Needles

Originator

Otsuka (Japan)

The Uses of Cilostazol

antibacterial; LD50(iv) 280mg/kg(mouse)

The Uses of Cilostazol

A potent phosphodiesterase III A (PDE3A) inhibitor (IC50=0.2uM) and inhibitor of adenosine uptake. Has antimitogeni, antithrombotic, vasodilatory and cardiotonic properties in vivo. Also affects lipid levels in vivo

The Uses of Cilostazol

An inhibitor of phosphodiesterase III

Indications

Indicated for the alleviation of symptoms of intermittent claudication (pain in the legs that occurs with walking and disappears with rest).

Background

Cilostazol is a quinolinone derivative and antiplatelet agent with vasodilating properties that has been used in the symptomatic treatment of intermittent claudication in patients with peripheral ischaemia. It is marketed under the brand name Pletal by Otsuka Pharmaceutical Co.. Cilostazol works by inhibiting both primary and secondary aggregation and reducing calcium-induced contractions.

What are the applications of Application

Cilostazol is a PDE inhibitor, antimitogenic, antithrombotic, and cardiotonic agent

Definition

ChEBI: A lactam that is 3,4-dihydroquinolin-2(1H)-one in which the hydrogen at position 6 is substiuted by a 4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy group.

brand name

Pletal (Otsuka);Reta.

General Description

Cilostazol is a potent cyclic nucleotide phosphodiesterase inhibitor. It is mainly used as antiplatelet agent.

Biological Activity

Potent phosphodiesterase III A (PDE3A) inhibitor (IC 50 = 0.2 μ M) and inhibitor of adenosine uptake. Has antimitogenic, antithrombotic, vasodilatory and cardiotonic properties in vivo . Also affects lipid levels in vivo .

Mechanism of action

Cilostazol exhibits greater selectivity than dipyridamole as an inhibitor of PDE3A. The drug does not affect the other PDEs (PDEs 1, 2, or 4). Cilostazol reversibly inhibit platelet aggregation induced by a number of stimuli, such as thrombin, ADP, collagen, or stress from exercise. Additionally, cilostazol inhibits adenosine uptake, leading to increased activity of adenosine at A1 and A2 receptors.

Pharmacokinetics

Cilostazol reduces the 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.

Clinical Use

Cilostazol, a quinolinone derivative, is a potent orally active antiplatelet drug approved for the treatment of intermittent claudication (a peripheral artery disease resulting from blockage of blood vessels in the limbs).

Drug interactions

Potentially hazardous interactions with other drugs
Anagrelide: avoid concomitant use. Antibacterials: concentration increased by clarithromycin and erythromycin - consider reducing cilostazol dose.
Antifungals: concentration possibly increased by ketoconazole and itraconazole - consider reducing cilostazol dose.
Antivirals: concentration possibly increased by boceprevir, ritonavir and telaprevir - reduce cilostazol dose to 50 mg twice daily.
Calcium-channel blockers: concentration increased by diltiazem - consider reducing cilostazol dose.
Ulcer-healing drugs: concentration increased by omeprazole - consider reducing cilostazol dose.

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.

Metabolism

Cilostazol is rapidly absorbed after oral administration, particularly with a high-fat meal, which greatly increases its bioavailability to approximately 90%. It is extensively metabolized in the liver by various cytochromes. The most important cytochromes appear to be CYP3A4 and, to lesser extent, by CYP2C19, with an elimination half-life of approximately 11 to 13 hours. Among the various metabolites produced (11 metabolites are known), the two major metabolites are 3,4-dehydrocilostazol and 4′-trans-hydroxycliostazol. These two metabolites are pharmacologically active. Studies indicate that the concomitant administration of cilostazol with CYP3A inhibitors can greatly increase cilostazol blood concentrations, and a dose reduction may be required. Similar results are seen when CYP2C19 is inhibited, leading to decreased formation of 4-trans-hydroxycliostazol and significant increases in cilostazol and 3,4-dehydrocilostazol.

storage

Store at RT

References

1) Schror (2002) The pharmacology of cilostazol; Diabetes Obes. Metab., 4 S14