1.1. Adults
Platelet aggregation inhibitors (PAIs) are FDA-approved to reduce thrombotic cardiovascular events in patients with a history of ischemic stroke, or to prevent stroke in patients with predisposing factors for atherosclerosis or symptomatic cerebrovascular disease. Cilostazol is FDA approved to reduce symptoms of intermittent claudication. PAIs work by interfering with pathways that promote normal platelet function: inhibiting cyclooxygenase-1 (e.g., aspirin); inhibiting adenosine uptake into platelets, resulting in increased cyclic-3’,5’-adenosine monophosphate (cAMP) and adenosine levels (e.g., dipyridamole); inhibiting the adenosine diphosphate (ADP) P2Y12 receptor on the platelet surface and blocking activation of the glycoprotein GP IIb/IIIa complex (e.g., clopidogrel, prasugrel, ticagrelor); or inhibiting phosphodiesterase III (e.g., cilostazol) [1-8].
Aspirin is also available as combination therapy with dipyridamole, pairing two antiplatelet agents with different mechanisms of action for secondary stroke prevention.1,2,8 Maximum recommended adult dosages for PAIs are summarized in Tables 1 and 2. Medication profiles identifying patients prescribed dosages exceeding these recommendations will be reviewed.
| Drug Name | Dosage Form/Strength | Treatment Indication | Maximum Recommended Dosage |
|---|---|---|---|
| cilostazol (generics) | 50 mg, 100 mg tablets | intermittent claudication | 100 mg twice daily |
| clopidogrel (Plavix, generics) | 75 mg, 300 mg tablets | ACS, including UA/NSTEMI and STEMI | Initial: 300 mg loading dose, followed by 75 mg once daily for up to 12 months in combination with aspirin, followed by aspirin indefinitely |
| Rate reduction of MI and stroke in patients with recent MI or stroke, or established peripheral vascular disease | 75 mg/day | ||
| dipyridamole (generics) | 25 mg, 50 mg, 75 mg tablets | prevention of postoperative thrombotic complications in patients with prosthetic heart valves | 400 mg/day (divided doses, in combination with warfarin) |
| prasugrel (Effient, generics) | 5 mg, 10 mg tablets | ACS in patients to be managed with PCI | following a 60 mg loading dose, 10 mg/day+ in combination with aspirin |
| ticagrelor (Brilinta) | 60 mg, 90 mg tablets | reduce risk of death, MI, and stroke in patients with ACS, history of MI, or acute ischemic stroke/ high risk transient ischemic attack | following a 180 mg loading dose, 90 mg twice daily^ in combination with aspirin |
| reduce risk of first MI or stroke in patients with CAD at high risk of events | 60 mg twice daily in combination with aspirin |
Legend:
- ACS = acute coronary syndrome
- CAD = coronary artery disease
- MI = myocardial infarction
- NSTE-ACS = non-ST-elevation acute coronary syndrome
- NSTEMI = non-ST-elevation myocardial infarction
- PAD = peripheral arterial disease
- PCI = percutaneous coronary intervention
- STEMI = ST-elevation myocardial infarction
- TIA = transient ischemic attack
- UA = unstable angina
- + patients 75 years or older or weigh less than 60 kg may use prasugrel 5 mg/day as maintenance therapy in combination with aspirin to reduce bleeding risk
- ^ ticagrelor dosages are decreased to 60 mg twice daily after 12 months
| Drug Name | Dosage Form/ Strength | Treatment Indication | Maximum Recommended Dosage |
|---|---|---|---|
| dipyridamole/aspirin (generics) | 200 mg/25 mg extended-release capsule | secondary stroke prevention | 200 mg/25 mg twice daily |