PURPOSE: This review aims to gather existing literature on the clinical effects of ticagrelor after inhibiting adenosine uptake.
METHODOLOGY: The current study reviewed literature related to the effects of ticagrelor on adenosine metabolism. The review also examined the drug's biological effects and clinical characteristics to see how it could be used in a clinical setting.
RESULTS: Many studies have shown that ticagrelor can inhibit equilibrative nucleoside transporter 1 (ENT1). This inhibition leads to intracellular adenosine uptake, increased adenosine half-life and plasma concentration levels and an enhanced adenosine-mediated biological effect.
CONCLUSIONS: Based on the studies reviewed, it was found that ticagrelor essentially inhibits adenosine absorption of adenosine into cells through ENT1, which increases the concentration in the blood and subsequently increases the protection of the heart muscle by adenosine. It also prevents platelet aggregation, and extends the biological effects of coronary arteries. Moreover, it leads to a lower mortality rate in acute coronary syndrome (ACS) patients.
METHODOLOGY: We performed a systematic review of randomized controlled trials (RCTs) to compare the effectiveness and safety of ticagrelor vs. clopidogrel in elderly patients with CHD. We selected eligible RCTs based on specified study criteria following a systematic search of PubMed and Scopus databases from January 2007 to May 2021. Primary efficacy outcomes assessed were major adverse cardiovascular events (MACEs), myocardial infarction (MI), stent thrombosis (ST), and all-cause death. The secondary outcome assessed was major bleeding events. We used RevMan 5.3 software to conduct a random-effects meta-analysis and estimated the pooled incidence and risk ratios (RRs) with 95% confidence intervals (CIs) for ticagrelor and clopidogrel.
RESULTS: Data from 6 RCTs comprising 21,827 elderly patients were extracted according to the eligibility criteria. There was no significant difference in the MACE outcome (incidence: 9.23% vs. 10.57%; RR = 0.95, 95% CI = 0.70-1.28, p = 0.72), MI (incidence: 5.40% vs. 6.23%; RR = 0.94, 95% CI= 0.69-1.27, p = 0.67), ST (incidence: 2.33% vs. 3.17%; RR = 0.61, 95% CI= 0.32-1.17, p = 0.13), and all-cause death (4.29% vs. 5.33%; RR = 0.86, 95% CI = 0.65-1.12, p = 0.25) for ticagrelor vs. clopidogrel, respectively. In addition, ticagrelor was not associated with a significant increase in the rate of major bleeding (incidence: 9.98% vs. 9.33%: RR = 1.37, 95% CI = 0.97-1.94, p = 0.07) vs. clopidogrel.
CONCLUSIONS: This study did not find evidence that ticagrelor is significantly more effective or safer than clopidogrel in elderly patients with CHD.