Cilostazol

Cilostazol is a phosphodiesterase type 3 inhibitor. It widens arteries and makes platelets less sticky, which can improve blood flow to the leg muscles. Intermittent claudication is the cramping calf, thigh or buttock pain that comes on with walking and eases with rest, caused by narrowed leg arteries. The UK SmPC licenses the medicine to increase both the maximum and the pain-free walking distance in people with claudication who have no pain at rest and no tissue breakdown (Fontaine stage II peripheral arterial disease). It is a second-line option, meant for when stopping smoking, supervised exercise and other measures have not helped enough.

Two strengths can be selected, 50 mg and 100 mg, and both come in 30, 60, 90, 120, 180 or 360 tablets. At the standard dose of 100 mg twice a day, 60 tablets cover roughly a month. The 50 mg tablet is mainly used where a lower dose is required because of interacting medicines. The tablets supplied are an imported generic, so packaging may not match UK packs.

The SmPC recommends 100 mg twice daily, taken 30 minutes before breakfast and before the evening meal; taking it with food raises blood levels and the likelihood of side effects. The dose is reduced to 50 mg twice daily for people also taking strong CYP3A4 inhibitors, such as some macrolide antibiotics, azole antifungals and protease inhibitors, or strong CYP2C19 inhibitors such as omeprazole. Benefit may take several weeks to appear; the patient should be reassessed after three months and treatment stopped if walking has not improved. Lifestyle changes, cholesterol-lowering treatment and antiplatelet therapy should continue alongside it.

Generic cilostazol 50 mg and 100 mg tablets hold UK marketing authorisations, for example from Viatris, and are prescription-only medicines (POM). NICE technology appraisal TA223 does not recommend Cilostazol for intermittent claudication, although people already on it may carry on if they and their clinician agree. Treatment should be started by a doctor experienced in managing claudication, and the prescriber decides whether it is appropriate.

The medicine must not be used in heart failure, in severe kidney impairment (creatinine clearance 25 ml/min or less), in moderate or severe liver impairment, or during pregnancy. It is also ruled out where there is a tendency to bleed, such as an active stomach ulcer, a haemorrhagic stroke in the past six months, proliferative diabetic retinopathy or poorly controlled blood pressure. Other exclusions include a history of ventricular tachycardia or fibrillation, a prolonged QTc interval, severe tachyarrhythmia, unstable angina, or a heart attack or coronary procedure within six months. It should not be combined with two or more other antiplatelet or anticoagulant medicines, such as aspirin, clopidogrel, warfarin, apixaban or rivaroxaban.

Headache affects more than three in ten users and is a common reason for stopping. Diarrhoea and loose or abnormal stools each occur in over 15%. Palpitations, a fast heartbeat, dizziness, ankle swelling (oedema) and nosebleeds or bruising are also reported. These effects are often mild and may settle, sometimes with a lower dose. Chest pain, fainting, unusual bleeding or black stools need prompt medical attention, so tell your doctor about any of these while taking Cilostazol.