Question

Describe mechanism of action, indications, dosage, and side effects of the following drugs:
Cilostazol.

Hint:

Cilostazol is effective for intermittent claudication but should be avoided in patients with heart failure due to its potential to worsen symptoms.

Answer 1

Step 1: Mechanism of Action.
Cilostazol is a phosphodiesterase III inhibitor that works by inhibiting the enzyme phosphodiesterase III. This inhibition increases cyclic AMP (cAMP) levels within the platelets and smooth muscle cells, leading to vasodilation and inhibition of platelet aggregation. Cilostazol thus improves blood flow by preventing platelet clumping and dilating blood vessels, particularly in the lower extremities.

Step 2: Indications.
Cilostazol is primarily indicated for the treatment of intermittent claudication (IC) in patients with peripheral arterial disease (PAD). It is used to improve walking distance and relieve symptoms of pain and discomfort caused by reduced blood flow in the legs.

Step 3: Dosage.
The typical dosage of cilostazol is 100 mg twice daily, taken orally. Dosage adjustments may be necessary in patients with renal or hepatic impairment. Cilostazol should be taken on an empty stomach, 30 minutes before or 2 hours after meals, to optimize absorption.

Step 4: Side Effects.
The common side effects of cilostazol include:
1. Headache: A frequent side effect, especially during the initiation of treatment.
2. Diarrhea: This is another common side effect of cilostazol.
3. Palpitations or Tachycardia: Some patients may experience an increase in heart rate.
4. Peripheral edema: Swelling in the legs or feet can occur.
5. Dizziness: Light-headedness or dizziness may occur, particularly in older patients.
It is contraindicated in patients with congestive heart failure (CHF) due to the risk of exacerbating the condition.