Clinical evidence of interaction between clopidogrel and proton pump inhibitors

Retrospective Analysis of Potential Adverse Drug Interactions in the Drugs Prescribed to the Elderly at a Tertiary Health Care Center in Raipur, Chhattisgarh, Central India

Background The elderly population differs from adults in having various physiological changes and multiple diseases, which demand the use of multiple medications. The practice of polypharmacy in the elderly leads to numerous harmful effects like adverse drug reactions, adverse drug-drug interactions (DDIs), poor compliance, etc. Methodology This study collected 295 case files of elderly patients retrospectively in the Departments of General Medicine, Cardiology and Nephrology after obtaining Institute Ethics Committee approval to look for the potential adverse DDIs with their severity according to the clinical significance. Results and interpretation The total number of adverse DDIs identified was 156, the maximum in Category 'C.' Salbutamol plus carvedilol/propranolol, ramipril plus telmisartan and ivabradine plus diltiazem were the adverse DDIs categorized under severity 'X'. The identified DDIs were categorised according to the mechanism such as increased bleeding risk, hypokalemia, hyperkalaemia, reduced effect of drugs and increased effect of drugs.  Conclusion Polypharmacy can lead to several adverse consequences in the elderly, of which adverse DDIs play a crucial role in harmful health outcomes. This study brings out the significance of predicting drug interactions beforehand which can reduce the risk of bleeding and other risks of hyper/hypokalaemia, hyponatremia and hypoglycaemia.

An Updated Review of Genetic Associations With Severe Adverse Drug Reactions: Translation and Implementation of Pharmacogenomic Testing in Clinical Practice

Adverse drug reactions (ADR) remain the major problems in healthcare. Most severe ADR are unpredictable, dose-independent and termed as type B idiosyncratic reactions. Recent pharmacogenomic studies have demonstrated the strong associations between severe ADR and genetic markers, including specific HLA alleles (e.g., HLA-B*15:02/HLA-B*57:01/HLA-A*31:01 for carbamazepine-induced severe cutaneous adverse drug reactions [SCAR], HLA-B*58:01 for allopurinol-SCAR, HLA-B*57:01 for abacavir-hypersensitivity, HLA-B*13:01 for dapsone/co-trimoxazole-induced SCAR, and HLA-A*33:01 for terbinafine-induced liver injury), drug metabolism enzymes (such as CYP2C9*3 for phenytoin-induced SCAR and missense variant of TPMT/NUDT15 for thiopurine-induced leukopenia), drug transporters (e.g., SLCO1B1 polymorphism for statin-induced myopathy), and T cell receptors (Sulfanilamide binding into the CDR3/Vα of the TCR 1.3). This mini review article aims to summarize the current knowledge of pharmacogenomics of severe ADR, and the potentially clinical use of these genetic markers for avoidance of ADR.

Comparison Between Aspirin and Clopidogrel in Secondary Stroke Prevention Based on Real-World Data

Background

Clopidogrel was thought to be superior to aspirin for secondary prevention of vascular diseases in clinical trials. In this study we assessed the safety and efficacy of clopidogrel versus aspirin in real‐world practice by using the Taiwan Stroke Registry.

Methods and Results

Patients with ischemic stroke (2006–2016) on aspirin or clopidogrel for secondary stroke prevention were identified in the Taiwan Stroke Registry. Stroke recurrence and mortality rates in patients receiving aspirin (N=34 679) were compared with those receiving clopidogrel (N=7611) during a 12‐month follow‐up period. Propensity score matching and conditional Cox proportional hazards regression model were applied to control confounding factors with 6443 patients in each group. After propensity score matching, stroke recurrence rates were comparable between groups, with 223 patients in the aspirin (3.46%) and 244 in the clopidogrel group (3.79%) (hazard ratio=1.13, 95% confidence interval=0.89–1.43, P=0.311). However, the mortality rate was significantly higher in the clopidogrel group (362 patients, 5.62%) than in the aspirin group (302 patients, 4.69%) (hazard ratio=1.30, 95% confidence interval=1.07–1.58, P=0.008). Results were consistent before and after propensity score matching.

Conclusions

Clopidogrel was as effective as aspirin for prevention of recurrent stroke in real‐world practice. However, the mortality rate was significantly higher in the clopidogrel than in the aspirin group.

The effect of proton pump inhibitors on fracture risk: report from the Canadian Multicenter Osteoporosis Study

A large Canadian cohort was studied over 10 years to see if proton pump inhibitor (PPI) use increased the risk of sustaining a fragility fracture. We found an increased risk of fracture in individuals who used PPIs. The risk remained after controlling for other known fracture risk factors.

INTRODUCTION

Multiple retrospective studies have linked proton pump inhibitor use with increased risk of fragility fracture. We prospectively studied the association between PPI use and fracture in a large cohort over a 10-year period while controlling for known fracture risk factors.

METHODS

We studied 9,423 participants in the Canadian Multicenter Osteoporosis Study. The cohort was formed in 1995-1997 and followed for 10 years with monitoring for incident nontraumatic fracture and PPI use. Cox regression analyses were used to assess the association between PPI use and incident fracture risk.

RESULTS

PPI use, coded as a time-dependent variable, was associated with a shorter time to first nontraumatic fracture, hazard ratio (HR)=1.75 (95% confidence interval (CI) 1.41-2.17, p<0.001). After controlling for multiple risk factors, including femoral neck bone density, the association remained significant, HR=1.40 (95% CI 1.11-1.77, p=0.004). Similar results were obtained after controlling for bisphosphonate use, using PPI "ever" use, or when the outcome was restricted to hip fracture.

CONCLUSIONS

In this large prospective population-based cohort study, we found an association between PPI use and increased risk of fragility fracture. Although the increased risk found was modest, this finding is important, given the high prevalence of PPI use and the excess morbidity and mortality associated with osteoporosis-related fractures.

Effects of pantoprazole on dual antiplatelet therapy in stable angina pectoris patients after percutaneous coronary intervention

BACKGROUND

Our aim was to prospectively assess the potential influence of pantoprazole therapy on the antiplatelet effects of acetylsalicylic acid (ASA) and clopidogrel (CLO) in stable angina pectoris (SAP) patients after percutaneous coronary intervention (PCI).

METHODS

Forty-four patients with SAP (CCS I-III) and successful PCI with stent implantation were enrolled into the study. The patients were divided into group proton pump inhibitors (PPI): 23 patients with indications for PPI (F/M = 9/14; age = 64 ± 9; standard therapy + 20 mg pantoprazole) and the control group (group C): 21 patients (F/M = 6/15; age = 64 ± 8; standard therapy). The platelet function analysis in whole blood based on impedance aggregometry (ASPI, COL, ADP, TRAP tests) using Multiplate--V2.02.11 was performed 18-24 h after the PCI + CLO loading dose (600 mg) and 30 days after PCI.

RESULTS

Both baseline patient characteristics and clinical outcomes were comparable between the study groups. There were no differences in the mean values of the platelets (PTL) tests measured at the 30(th) day after PCI between both groups (PPI vs. C: ASPI: 24.6 ± 10.0 vs. 42.1 ± 14.8 U, COL: 32.9 ± 8.6 vs. 34.0 ± 7.7 U, ADP: 26.8 ± 12.4 vs. 30.4 ± 8.1 U, TRAP: 78.7 ± 16.6 vs. 78.1 ± 22.6 U, p = ns). The mean delta values of the PTL tests (18-24 h post-PCI/30 days post-PCI) were also comparable between the groups. The PTL aggregometry results were related to time (ADP, ASPI, TRAP vs. time, p = 0.001; COL vs. time, p = 0.03)--the baseline values of ADP, ASPI, COL and TRAP tests were smaller than those measured after the one-month observation.

CONCLUSION

Pantoprazole treatment does not impair the efficacy of dual antiplatelet therapy in patients with SAP after PCI.

Clopidogrel and proton pump inhibitors - where do we stand in 2012?

Clopidogrel in association with aspirine is considered state of the art of medical treatment for acute coronary syndrome by reducing the risk of new ischemic events. Concomitant treatment with proton pump inhibitors in order to prevent gastrointestinal side effects is recommended by clinical guidelines. Clopidogrel needs metabolic activation predominantly by the hepatic cytochrome P450 isoenzyme Cytochrome 2C19 (CYP2C19) and proton pump inhibitors (PPIs) are extensively metabolized by the CYP2C19 isoenzyme as well. Several pharmacodynamic studies investigating a potential clopidogrel-PPI interaction found a significant decrease of the clopidogrel platelet antiaggregation effect for omeprazole, but not for pantoprazole. Initial clinical cohort studies in 2009 reported an increased risk for adverse cardiovascular events, when under clopidogrel and PPI treatment at the same time. These observations led the United States Food and Drug Administration and the European Medecines Agency to discourage the combination of clopidogrel and PPI (especially omeprazole) in the same year. In contrast, more recent retrospective cohort studies including propensity score matching and the only existing randomized trial have not shown any difference concerning adverse cardiovascular events when concomitantly on clopidogrel and PPI or only on clopidogrel. Three meta-analyses report an inverse correlation between clopidogrel-PPI interaction and study quality, with high and moderate quality studies not reporting any association, rising concern about unmeasured confounders biasing the low quality studies. Thus, no definite evidence exists for an effect on mortality. Because PPI induced risk reduction clearly overweighs the possible adverse cardiovascular risk in patients with high risk of gastrointestinal bleeding, combination of clopidogrel with the less CYP2C19 inhibiting pantoprazole should be recommended.