Platelet aggregation inhibitors
Platelet aggregation inhibitors, also called antiplatelet drugs, are "drugs or agents which antagonize or impair any mechanism leading to blood platelet aggregation, whether during the phases of activation and shape change or following the dense-granule release reaction and stimulation of the prostaglandin-thromboxane system."[1]
Classification
Adenosine diphosphate (ADP) blockers
These drugs bind to and block the purinergic P2Y12 receptors. These receptors are G-protein-coupled receptors and are subreceptors of purinergic P2Y receptor.
Purinergic P2Y Receptor Antagonists
The purinergic P2Y receptor antagonists include the thienopyridines clopidogrel (a prodrug), ticlopidine, and the prodrug prasugrel.[2]
Additional antagonists are cangrelor and ticagrelor. Cangrelor is quick acting and reversible. Ticagrelor is an adenosine analog that reversibly binds to the purinergic P2Y12 receptor and also does not require conversion to an active form.
Cyclooxygenase-1 blockers
Cyclooxygenase-1 blockers include aspirin.
Glycoprotein IIb/IIIa inhibitors
Inhibitors of the platelet glycoprotein GPIIb-IIIa complex (GPIs) include the monoclonal antibody abciximab and the small-molecule agents tirofiban and eptifibatid.
Protease-activated receptors (PAR-1) antagonists
Vorapaxar
Thromboxane-A synthase inhibitors
This includes dipyridamole.
Effectiveness
A recent review conducted by the National Institute for Health Research Health Technology Assessment programme concluded:[3]
- "The most cost-effective treatment for patients with ischaemic stroke/TIA is clopidogrel followed by MRD + ASA followed by ASA."
- "For patients with MI, ASA followed by clopidogrel."
- "For patients with established peripheral arterial disease or multivascular disease, clopidogrel followed by ASA."
"The available evidence demonstrates that the use of clopidogrel plus aspirin is associated with a reduction in the risk of cardiovascular events and an increased risk of bleeding compared with aspirin alone. Only in patients with acute non-ST coronary syndrome benefits outweigh harms" according to the Cochrane Collaboration.[4]
Drug toxicity
Drug toxicity, specifically hemorrhage, is increased if clopidogrel is combined with aspirin.[5]
References
- ↑ Anonymous (2024), Platelet aggregation inhibitors (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Sudlow CL, Mason G, Maurice JB, Wedderburn CJ, Hankey GJ (2009). "Thienopyridine derivatives versus aspirin for preventing stroke and other serious vascular events in high vascular risk patients.". Cochrane Database Syst Rev (4): CD001246. DOI:10.1002/14651858.CD001246.pub2. PMID 19821273. Research Blogging.
- ↑ Greenhalgh J, Bagust A, Boland A, Martin Saborido C, Oyee J, Blundell M et al. (2011). "Clopidogrel and modified-release dipyridamole for the prevention of occlusive vascular events (review of Technology Appraisal No. 90): a systematic review and economic analysis.". Health Technol Assess 15 (31): 1-178. DOI:10.3310/hta15310. PMID 21888837. Research Blogging.
- ↑ Squizzato A, Keller T, Romualdi E, Middeldorp S (2011). "Clopidogrel plus aspirin versus aspirin alone for preventing cardiovascular disease.". Cochrane Database Syst Rev 1: CD005158. DOI:10.1002/14651858.CD005158.pub3. PMID 21249668. Research Blogging.
- ↑ Shehab, Nadine; Laurence S. Sperling, Scott R. Kegler, Daniel S. Budnitz (2010-11-22). "National Estimates of Emergency Department Visits for Hemorrhage-Related Adverse Events From Clopidogrel Plus Aspirin and From Warfarin". Arch Intern Med 170 (21): 1926-1933. DOI:10.1001/archinternmed.2010.407. Retrieved on 2010-11-23. Research Blogging.