Cilostazol
Pletal
Phosphodiesterase-3 inhibitor — antiplatelet + vasodilator
Inhibits PDE3 → ↑ cAMP → antiplatelet + arterial vasodilation. Improves claudication walking distance.
Indications
- •Intermittent claudication (peripheral artery disease)
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Claudication | 100 mg PO BID (50 mg if on CYP3A4/2C19 inhibitors) | — |
Pharmacokinetics
Onset weeks for claudication benefit. Half-life ~11 h. Hepatic CYP3A4/2C19.
Side effects
- !Headache, palpitations, diarrhea
- !Contraindicated in heart failure (class effect of PDE3 inhibitors → ↑ mortality)
Contraindications
- ×Heart failure of ANY severity (PDE3 inhibitors ↑ mortality — class effect)
- ×Active bleeding
Clinical pearls
- ★ASRA neuraxial: hold ~2 days before neuraxial procedure.
- ★CONTRAINDICATED in any degree of heart failure (like all PDE3 inhibitors — milrinone/inamrinone).
Other drugs in Antiplatelets
- Aspirin
Irreversibly acetylates COX-1 → blocks thromboxane A2 for the platelet's lifespan (~7–10 days). Antiplatelet effect at low dose; analgesic/anti-inflammatory at high dose.
- Clopidogrel
Prodrug → active metabolite (CYP2C19) irreversibly blocks the platelet P2Y12 ADP receptor for the platelet lifespan.
- Prasugrel
Prodrug → active metabolite irreversibly blocks P2Y12. More potent + more consistent than clopidogrel (not CYP2C19-limited), but more bleeding.
- Ticagrelor
Directly and REVERSIBLY inhibits P2Y12 (not a prodrug, not thienopyridine). Faster onset/offset than clopidogrel.
- Ticlopidine
Irreversibly blocks P2Y12. Largely replaced by clopidogrel due to hematologic toxicity.
- Abciximab
Fab fragment that irreversibly blocks the platelet GP IIb/IIIa receptor → prevents fibrinogen cross-linking (final common pathway of aggregation).
- Eptifibatide
Reversibly blocks GP IIb/IIIa (final common pathway of platelet aggregation). Short-acting.
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
- •ASRA regional anesthesia in the anticoagulated patient guidelines, 2018
