What is cilostazol, and how does it work (mechanism of action)?
Cilostazol is a medication for the treatment of intermittent claudication, a condition caused by narrowing of the arteries that supply the legs with blood. Patients with intermittent claudication develop pain when they walk because not enough oxygen-containing blood reaches the active leg muscles. Cilostazol reduces the pain of intermittent claudication by dilating the arteries, thereby improving the flow of blood and oxygen to the legs. (It does this by decreasing the action of an enzyme, phosphodiesterase III.) It also reduces the ability of blood to clot. Cilostazol enables patients with intermittent claudication to walk longer and faster before developing pain. Cilostazol has a different mechanism of action than pentoxifylline (Trental), the other drug approved for intermittent claudication. (Pentoxifylline improves blood flow by making it easier for red blood cells to pass through vessels. It also decreases the viscosity of blood.). The FDA approved cilostazol in January 1999.
What brand names are available for cilostazol?
Pletal
Is cilostazol available as a generic drug?
Yes
Do I need a prescription for cilostazol?
Yes
What are the side effects of cilostazol?
The most common adverse effects of cilostazol are:
- headache,
- abdominal pain,
- diarrhea,
- abnormal stool,
- upper respiratory tract infections,
- runny nose,
- nausea,
- fluid retention,
- dizziness and
- abnormal heartbeats.
Other important side effects which have also been reported with cilostazol include a reduction in numbers of white blood cells and platelets. Severe skin reactions also have been reported.
Cilostazol inhibits the enzyme phosphodiesterase III. Other drugs that inhibit this enzyme have caused death in individuals with heart failure. Therefore, individuals with heart failure should not use cilostazol.
What is the dosage for cilostazol?
The dose is 100 mg twice daily. Cilostazol should be taken at least half an hour before or two hours after dinner and breakfast to prevent food from affecting its absorption.

SLIDESHOW
How to Lower Blood Pressure: Exercise and Tips See SlideshowWhich drugs or supplements interact with cilostazol?
Erythromycin (E.E.S, Erythrocin), omeprazole (Prilosec) and diltiazem (Cardizem) increase the concentration of cilostazol by blocking the action of enzymes that destroy cilostazol. Though not specifically studied, a similar interaction could occur with ketoconazole (Nizoral), itraconazole (Sporanox), fluconazole (Diflucan), miconazole (Monistat), fluvoxamine (Luvox), fluoxetine (Prozac), nefazodone (Serzone) and sertraline (Zoloft). Diltiazem (Cardizem) and omeprazole (Prilosec) also increase concentrations of cilostazol.
Higher concentrations of cilostazol could increase the possibility of toxic effects. Therefore, a dose of 50 mg twice daily should be considered when drugs that may increase the concentration of cilostazol also are being used.
Combining pletal with other drugs that interfere with the blood clotting process may increase the likelihood of bleeding.
A high fat meal increases the absorption of cilostazol. Grapefruit juice could increase the concentration of cilostazol. Therefore, grapefruit juice should not be taken by patients on cilostazol.
Is cilostazol safe to take if I'm pregnant or breastfeeding?
The use of cilostazol in pregnancy has not been adequately studied.
Cilostazol has not been adequately studied in women who are breastfeeding.
Summary
Cilostazol (Pletal) is a drug prescribed to improve walking speed and distance in individuals with intermittent claudication. Side effects, drug interactions, warnings and precautions, and pregnancy safety should be reviewed prior to taking this medication.
Related Disease Conditions
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Gangrene
Gangrene may result when blood flow to a tissue is lost or not adequate to keep the tissue alive. There are two types of gangrene: wet and dry. All cases of wet gangrene are infected by bacteria. Most cases of dry gangrene are not infected. If wet gangrene goes untreated, the patient may die of sepsis within hours or days. Dry gangrene usually doesn't cause the patient to die. Symptoms of dry gangrene include numbness, discoloration, and mummification of the affected tissue. Wet gangrene symptoms include swelling, pain, pus, bad smell, and a black appearance of the affected tissue. Treatment depends upon the type of gangrene and how much tissue is compromised by the gangrene.
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Peripheral Vascular Disease
Peripheral vascular disease (PVD) refers to diseases of the blood vessels (arteries and veins) located outside the heart and brain. While there are many causes of peripheral vascular disease, doctors commonly use the term peripheral vascular disease to refer to peripheral artery disease (peripheral arterial disease, PAD), a condition that develops when the arteries that supply blood to the internal organs, arms, and legs become completely or partially blocked as a result of atherosclerosis. Peripheral artery disease symptoms include intermittent leg pain while walking, leg pain at rest, numbness in the legs or feet, and poor wound healing in the legs or feet. Treatment for peripheral artery disease include lifestyle measures, medication, angioplasty, and surgery.
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Claudication
Intermittent claudication, or pain and cramping in the lower leg is caused by inadequate blood flow to the leg muscles. This lack of blood flow causes a decrease in oxygen delivered to the muscles of the legs. Claudication is generally felt when walking and decreases with rest. In severe cases, claudication may be felt at rest. Narrowing of arteries cause claudication. Treatment includes exercise, medication, and in some cases surgery.
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
REFERENCE:
FDA Prescribing Information