Merck Manual

Please confirm that you are a health care professional

honeypot link

Acquired Platelet Dysfunction


David J. Kuter

, MD, DPhil, Harvard Medical School

Last full review/revision Jun 2020| Content last modified Jun 2020
Click here for Patient Education

Acquired platelet dysfunction, which is common, may result from aspirin, other nonsteroidal anti-inflammatory drugs (NSAIDs), or systemic disorders.

Acquired abnormalities of platelet function are very common. Causes include

  • Drugs

  • Systemic disorders

  • Cardiopulmonary bypass

Acquired platelet dysfunction is suspected and diagnosed when unusual or prolonged bleeding is observed and other possible diagnoses (eg, thrombocytopenia, coagulation abnormalities) have been eliminated. Platelet aggregation studies are unnecessary.


Aspirin, other NSAIDs, inhibitors of the platelet P2Y12 adenosine diphosphate (ADP) receptor (eg, clopidogrel, prasugrel, ticagrelor), and glycoprotein IIb/IIIa receptor inhibitors (eg, abciximab, eptifibatide, tirofiban) may induce platelet dysfunction. Sometimes this effect is incidental (eg, when the drugs are used to relieve pain and inflammation) and sometimes therapeutic (eg, when aspirin or the P2Y12 inhibitors are used for prevention of stroke or coronary thrombosis).

Aspirin and NSAIDs prevent cyclooxygenase-mediated production of thromboxane A2. This effect can last 5 to 7 days. Aspirin modestly increases bleeding in healthy people but may markedly increase bleeding in older patients and those with underlying platelet dysfunction or a severe coagulation disturbance (eg, patients receiving heparin, patients with severe hemophilia). Clopidogrel, prasugrel, and ticagrelor all can markedly reduce platelet function and increase bleeding.

A number of other drugs can also cause platelet dysfunction (1).

Systemic disorders

Uremia prolongs bleeding via unknown mechanisms. If bleeding is observed clinically in uremic patients, bleeding may be reduced with vigorous dialysis, cryoprecipitate administration, or desmopressin infusion. If necessary, increasing the hemoglobin concentration to > 10 g/dL by transfusion or by giving erythropoietin also reduces bleeding.

Cardiopulmonary bypass

As blood circulates through a pump oxygenator during cardiopulmonary bypass, platelets may become dysfunctional, prolonging bleeding. The mechanism appears to be activation of fibrinolysis on the platelet surface with resultant loss of the glycoprotein Ib/IX binding site for von Willebrand factor. Regardless of platelet count, patients who bleed excessively after cardiopulmonary bypass are often transfused with platelets. Giving an antifibrinolytic agent during bypass may preserve platelet function and reduce the need for transfusion.

General reference

  • Scharf RE: Drugs that affect platelet function. Semin Thromb Hemost 38(8): 865–883, 2012. doi: 10.1055/s-0032-1328881 Epub 2012 Oct 30.

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Test your knowledge

Management of Adverse Effects of Cancer Therapy
Nausea and vomiting are common adverse effects of either the cancer itself or of the treatment for cancer. Several drugs are available to administer prior to chemotherapy for anticipatory nausea and vomiting. Of these drugs, which of the following is the most effective yet the most expensive? 
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest