Pharmacodynamic effects of standard dose prasugrel versus high dose clopidogrel in non-diabetic obese patients with coronary artery disease

Oral drug dosing following bariatric surgery: General concepts and specific dosing advice

Bariatric or weight‐loss surgery is a popular option for weight reduction. Depending on the surgical procedure, gastric changes like decreased transit time and volume and increased pH, decreased absorption surface in the small intestine, decreased exposure to bile acids and enterohepatic circulation, and decreased gastrointestinal transit time may be expected. In the years after bariatric surgery, patients will also substantially lose weight. As a result of these changes, the absorption, distribution, metabolism and/or elimination of drugs may be altered. The purpose of this article is to report the general influence of bariatric surgery on oral drug absorption, and to provide guidance for dosing of commonly used drugs in this special population. Upon oral drug administration, the time to maximum concentration is often earlier and this concentration may be higher with less consistent effects on trough concentrations and exposure. Additionally, prescription of liquid formulations to bariatric patients is supported by some reports, even though the high sugar load of these suspensions may be of concern. Studies on extended‐release medications result in an unaltered exposure for a substantial number of drugs. Also, studies evaluating the influence of timing after surgery show dynamic absorption profiles. Although for this group specific advice can be proposed for many drugs, we conclude that there is insufficient evidence for general advice for oral drug therapy after bariatric surgery, implying that a risk assessment on a case‐by‐case basis is required for each drug.

Platelet reactivity and clinical outcomes in acute coronary syndrome patients treated with prasugrel and clopidogrel: a pre-specified exploratory analysis from the TROPICAL-ACS trial

Aims

The value of platelet function testing (PFT) in predicting clinical outcomes and guiding P2Y12-inhibitor treatment is uncertain. In a pre-specified sub-study of the TROPICAL-ACS trial, we assessed ischaemic and bleeding risks according to high platelet reactivity (HPR) and low platelet reactivity (LPR) to ADP in patients receiving uniform prasugrel vs. PFT-guided clopidogrel or prasugrel.

Methods and results

Acute coronary syndrome patients with PFT done 14 days after hospital discharge were included with prior randomization to uniform prasugrel for 12 months (control group, no treatment modification) vs. early de-escalation from prasugrel to clopidogrel and PFT-guided maintenance treatment (HPR: switch-back to prasugrel, non-HPR: clopidogrel). The composite ischaemic endpoint included cardiovascular death, myocardial infarction, or stroke, while key safety outcome was Bleeding Academic Research Consortium (BARC) 2–5 bleeding, from PFT until 12 months. We identified 2527 patients with PFT results available: 1266 were randomized to the guided and 1261 to the control group. Before treatment adjustment, HPR was more prevalent in the guided group (40% vs. 15%), while LPR was more common in control patients (27% vs. 11%). Compared to control patients without HPR on prasugrel (n = 1073), similar outcomes were observed in guided patients kept on clopidogrel [n = 755, hazard ratio (HR): 1.06 (0.57–1.95), P = 0.86] and also in patients with HPR on clopidogrel switched to prasugrel [n = 511, HR: 0.96 (0.47–1.96), P = 0.91]. In contrast, HPR on prasugrel was associated with a higher risk for ischaemic events in control patients [n = 188, HR: 2.16 (1.01–4.65), P = 0.049]. Low platelet reactivity was an independent predictor of bleeding [HR: 1.74 (1.18–2.56), P = 0.005], without interaction (Pint = 0.76) between study groups.

Conclusion

Based on this substudy of a randomized trial, selecting prasugrel or clopidogrel based on PFT resulted in similar ischaemic outcomes as uniform prasugrel therapy without HPR. Although infrequent, HPR on prasugrel was associated with increased risk of ischaemic events. Low platelet reactivity was a strong and independent predictor of bleeding both on prasugrel and clopidogrel.

A comparison of cangrelor, prasugrel, ticagrelor, and clopidogrel in patients undergoing percutaneous coronary intervention: A network meta-analysis

BACKGROUND

Newer P2Y12 inhibitors have more rapid onset of platelet inhibition compared with clopidogrel, especially the intravenous P2Y12 inhibitor cangrelor. Direct comparisons between cangrelor and oral P2Y12 inhibitors ticagrelor and prasugrel do not exist. Thus, we performed a network meta-analysis to directly and indirectly compare different P2Y12 inhibitors in patients undergoing percutaneous coronary intervention (PCI).

METHODS

MEDLINE/PubMed and ClinicalTrials.gov were searched for randomized controlled trials (RCTs) that compared at least two P2Y12 inhibitors including cangrelor, clopidogrel, prasugrel, and ticagrelor. Network meta-analysis with a Bayesian approach was performed to directly and indirectly compare the effects of the aforementioned P2Y12 inhibitors on clinical outcomes. Odds ratios with credible intervals (OR [CrIs]) were generated with random-effects models to compare outcomes.

RESULTS

This analysis included 15 RCTs with 54,025 patients randomized to cangrelor (n=12,475), clopidogrel (n=26,903), prasugrel (n=7455), or ticagrelor (n=7192) at time of PCI. Patients had a mean age of 63±10, 74% were male, and 82% underwent PCI for acute coronary syndrome. No significant differences between cangrelor and clopidogrel were found with respect to cardiovascular death (OR 1.01 [CrI 0.23-4.39]), myocardial infarction (OR 0.94 [CrI 0.69-1.25]), major adverse cardiac events (OR 0.91 [CrI 0.69-1.18]), stent thrombosis (OR 0.66 [CrI 0.37-1.19]), or major bleeding (OR 1.52 [CrI 0.79-2.98]). Rank probability data suggested that ticagrelor and prasugrel were better than cangrelor for reducing ischemic events, though these differences were not significant.

CONCLUSION

Despite rapid platelet inhibition provided by cangrelor, newer oral P2Y12 inhibitors such as ticagrelor and prasugrel have comparable clinical outcomes.

Obesity and Antiplatelets-Does One Size Fit All?

Antiplatelet therapy has become a cornerstone in the management of many vascular diseases. With growing antiplatelet options, attention has focused on their comparative effectiveness in specific patient populations. Perhaps one of the least defined factors influencing efficacy of these agents is body mass and obesity. Evidence from preclinical models established that obesity promotes inflammation that in turn enhances platelet reactivity. Thus, adiposity has the potential to diminish or alter the therapeutic effect of antiplatelet therapy. Pharmacodynamic analyses suggest a potential need for dose adjustments of antiplatelet therapy in obese patients. Yet, obese patients paradoxically have better outcomes after acute coronary syndromes. In this review, we identify a critical need for clinical studies with outcome data to enable the development of recommendations for optimal antiplatelet regimens in obese individuals. Until such data exists, healthcare providers should be aware of the potential impact of obesity on the efficacy of anti-platelet therapy.

Mean platelet volume and high-residual platelet reactivity in patients receiving dual antiplatelet therapy with clopidogrel or ticagrelor

OBJECTIVE

High on-treatment platelet reactivity (HRPR) is associated with a two- to ninefold increased risk of recurrent ischemic events among patients receiving dual antiplatelet therapy (DAPT) for coronary artery disease. However, its determinants are still poorly understood. The aim of the present study was to assess the impact of mean platelet volume (MPV) on platelet reactivity in patients receiving DAPT after an acute coronary syndrome or PCI.

METHODS

Patients treated with DAPT (acetylsalicylic acid [ASA] and clopidogrel or ticagrelor) were scheduled for platelet function assessment at 30 - 90 days post-discharge. By whole blood impedance aggregometry, HRPR was considered for ASPI test > 862 aggregation units (AU)*min (for ASA) and ADP test values ≥ 417 AU*min (for ADP-antagonists).

RESULTS

Our population is represented by a total of 487 patients on DAPT, divided according to MPV tertiles (< 10.4 fl; 10.4 - 11.29 fl; ≥ 11.3 fl). Larger-sized platelets were associated with use of statins (p < 0.001) and beta-blockers (p = 0.03), higher hemoglobin levels (p = 0.002) and lower platelets count (p < 0.001). Higher platelet reactivity was observed at ASPI test in patients with higher MPV (r = 0.12, p = 0.008), but not for ADP-mediated aggregation (r = -0.007, p = 0.88). However, a low prevalence of HRPR was observed with ASA, with no impact of MPV tertiles (1.2 vs 1.1 vs 1.6%, p = 0.70, adjusted OR [95% CI] = 1.05 [0.51 - 1.77], p = 0.87). MPV did not influence the prevalence of HRPR for ADP-antagonists (25.9 vs 1 vs 26.5%, p = 0.89; adjusted OR [95% CI] = 1.1 [0.84 - 1.45], p = 0.50) with similar results among the 259 patients receiving clopidogrel (adjusted OR [95% CI] = 1.15 [0.82 - 1.62], p = 0.43) and the 228 patients on ticagrelor (adjusted OR [95% CI] = 1.46 [0.84 - 2.55], p = 0.18).

CONCLUSION

In patients receiving DAPT, MPV does not affect the response to major antiplatelet therapies. In fact, MPV elevation does not influence the risk of HRPR with clopidogrel, ticagrelor or ASA.