A Systematic Review on the Effect of Common Medications on Platelet Count and Function: Which Medications Should Be Stopped Before Getting a Platelet-Rich Plasma Injection?

Background: Platelet-rich plasma (PRP) exerts its effect through the release of growth factors and cytokines from the platelet concentrate. Certain medications may affect platelet count or function, resulting in decreased efficacy of PRP injections. Purpose: To systematically review the literature regarding common medications and their effects on platelets to establish guidelines for which medications should be stopped before obtaining a PRP injection. Study Design: Systematic review; Level of evidence, 2. Methods: This review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A search for studies assessing the effect of common medications on platelet count or platelet function was performed of the PubMed, Cochrane Library, Web of Science, and OpenGrey databases. Inclusion criteria were as follows: drug studied was aspirin, acetaminophen, a nonsteroidal anti-inflammatory drug (NSAID), a statin, or gabapentin; human participants; and article in the English language. Risk of bias was assessed using the Cochrane Risk of Bias tool and the Risk of Bias in Non-randomised Studies-of Interventions tool. Results: A total of 1711 studies were identified through the initial search, with 20 studies meeting all inclusion criteria. No studies involving gabapentin met all inclusion criteria. Patients treated with aspirin (268 patients) or acetaminophen (13 patients) showed a significant decrease in platelet aggregation. Statin therapy (73 patients) did not result in a significant decrease in platelet aggregation. Patients who took NSAIDs (172 patients) demonstrated significantly decreased platelet aggregation only when treated with nonselective formulations. Those treated with cyclooxygenase (COX)-2-selective NSAIDs showed no significant difference in platelet aggregation. Treatment with aspirin, acetaminophen, statins, or NSAIDs did not lead to a significant decrease in platelet count. Conclusion: Aspirin, acetaminophen, and nonselective NSAIDs should be considered for suspension before a PRP injection because of their potential to diminish the effects of the injection. COX-2-selective NSAIDs and statins do not need to be withheld before a PRP injection.