Interaction between clopidogrel and proton-pump inhibitors and management strategies in patients with cardiovascular diseases

Are We Optimizing the Use of Dual Antiplatelet Therapy in Patients Hospitalized with Acute Myocardial Infarction?

BACKGROUND

Dual antiplatelet therapy (DAPT) is a mainstay treatment for hospital survivors of an acute myocardial infarction (AMI). However, there are limited data on the prescribing patterns of DAPT among patients hospitalized with AMI during recent years.

OBJECTIVE

To examine decade-long trends (2001-2011) in the use of DAPT versus antiplatelet monotherapy and patient characteristics associated with DAPT use.

METHODS

The study population consisted of 2389 adults hospitalized with an initial AMI at all 11 central Massachusetts medical centers on a biennial basis between 2001 and 2011. DAPT was defined as the discharge use of aspirin plus either clopidogrel or prasugrel. Logistic regression analysis was used to identify patient characteristics associated with DAPT use.

RESULTS

The average age of the study population was 65 years, and 69% of patients were discharged on DAPT. The use of DAPT at the time of hospital discharge increased from 49% in 2001 to 74% in 2011; this increasing trend was seen across all age groups, both sexes, types of AMI, and in those who underwent a PCI. After multivariable adjustment, patients 65-74 years old (adjusted odds ratio (aOR) = 0.53, 95% CI: 0.36-0.80) and those who underwent coronary artery bypass surgery (aOR = 0.11, 95% CI: 0.07-0.18) were less likely to have received DAPT, while men (aOR = 14.60, 95% CI: 10.66-19.98) and those who underwent cardiac catheterization and stenting (aOR = 14.60, 95% CI: 10.66-19.98) were significantly more likely to have received DAPT at discharge than respective comparison groups.

CONCLUSIONS

Between 2001 and 2011, the use of DAPT increased markedly among patients hospitalized with AMI. However, a significant proportion of patients were not discharged on this therapy. Greater awareness is needed to incorporate DAPT into the management of patients hospitalized with AMI.

East Asian perspective on the interaction between proton pump inhibitors and clopidogrel

Both proton pump inhibitors (PPIs) and clopidogrel are widely prescribed in the Asia-Pacific population. PPIs are the mainstay therapeutic agents for prophylaxis against aspirin gastropathy and for acid-related disorders including gastroesophageal reflux disease. They are also co-prescribed with oral anticoagulant agents and with dual-antiplatelet therapy for the treatment and prevention of gastrointestinal bleeding. Clopidogrel belongs to the drug class of thienopyridines and is currently the most widely prescribed oral anticoagulant agent either alone or in combination with aspirin. Platelet inhibition by clopidogrel is prone to significant inter-individual variability and is believed to be affected by several factors such as genetics and drug-drug interactions. Since it was first reported in 2009, the potential for drug-drug interactions between PPIs and clopidogrel has remained headline news, and its significance in clinical practice is the subject of an ongoing debate. For East Asian patients in particular, the clinical relevance of the interaction between PPIs and clopidogrel remains unclear because of conflicting data, as well as underrepresentation of East Asian subjects in landmark trials. Increased CYP2C19 genetic polymorphisms in individuals from Asia-Pacific countries only fuel the confusion. Recent studies in East Asian cohorts suggests that the potential of PPIs to attenuate the efficacy of clopidogrel could be minimized by the use of newer PPIs with weaker affinity for the CYP2C19 isoenzyme, namely, pantoprazole, dexlansoprazole, and rabeprazole. This review aims to help clinicians choose the most appropriate PPI for co-prescription with clopidogrel in patients from Asia-Pacific countries.

The decline effect in cardiovascular medicine: is the effect of cardiovascular medicine and stent on cardiovascular events decline over the years?

The term decline effect is referred to a diminution of scientifically discovered effects over time. Reasons for the decline effect are multifaceted and include publication bias, selective reporting, outcomes reporting bias, regression to the mean, scientific paradigm shift, overshadowing and habituation, among others. Such effects can be found in cardiovascular medicines through medications (e.g., aspirin, antithrombotics, proton pump inhibitor, beta-blockers, statins, estrogen/progestin, angiotensin converting enzyme inhibitor etc.), as well as with interventional devices (e.g., angioplasty, percutaneous coronary intervention, stents). The scientific community should understand the various dimensions of the decline effects, and effective steps should be undertaken to prevent or recognize such decline effects in cardiovascular medicines.

Risk of adverse cardiovascular outcomes and all-cause mortality associated with concomitant use of clopidogrel and proton pump inhibitors in elderly patients

OBJECTIVE

To examine the effect of concomitant use of clopidogrel and PPIs in a national sample of elderly Medicare beneficiaries (age ≥65 years).

METHODS

A nested case-control design was employed. A cohort of Medicare beneficiaries who initiated clopidogrel and did not have any gap of ≥30 days between clopidogrel fills between July 1, 2006 and December 31, 2008 was identified from a 5% national sample of Medicare claims data. Within this cohort, cases (beneficiaries who experienced any major cardiovascular event [MCE] [acute myocardial infarction, stroke, coronary artery bypass graft, or percutaneous coronary intervention] or all-cause mortality) and controls (beneficiaries who did not experience any MCE or all-cause mortality) were identified from inpatient and outpatient claims. Cases and controls were matched on age and the time to first clopidogrel fill. Conditional logistic regression was performed on the matched sample to evaluate the association between concomitant use of clopidogrel and PPIs and adverse health outcomes (MCEs and all-cause mortality).

RESULTS

A total of 43,159 clopidogrel users were identified. Among them, 15,415 (35.7%) received clopidogrel and a PPI concomitantly at any time during the study period, 3502 (8.1%) experienced a MCE, 7306 (17.1%) died, and a total of 9908 (22.8%) experienced the primary composite outcome (any MCE or all-cause mortality) during follow-up. The odds ratio (OR) for the primary composite outcome was 1.26 (95% confidence interval [CI]: 1.18-1.35). Secondary analyses indicated that elderly patients using clopidogrel and a PPI concomitantly were more likely to experience all-cause mortality (OR: 1.40; 95% CI: 1.29-1.53) as compared to those receiving clopidogrel only, but not MCEs (OR: 1.06; 95% CI: 0.95-1.18).

CONCLUSIONS

Concomitant use of clopidogrel and PPIs was associated with a slightly increased risk of all-cause mortality but not MCEs.

Spaced administration of PA32540 and clopidogrel results in greater platelet inhibition than synchronous administration of enteric-coated aspirin and enteric-coated omeprazole and clopidogrel

BACKGROUND

A common regimen for patients requiring dual-antiplatelet therapy who are at risk for gastrointestinal complications is the synchronous administration of enteric-coated (EC) aspirin, a proton pump inhibitor, and clopidogrel, although proton pump inhibitors have the potential for pharmacodynamic interaction with clopidogrel. Spaced administration of a clopidogrel and a single-tablet formulation of aspirin and immediate-release omeprazole (PA32540) was considered as an alternative that might reduce this potential pharmacodynamic interaction.

METHODS AND RESULTS

A randomized, open-label, crossover study was conducted in healthy subjects (n = 30). Two 7-day treatments were separated by 14-day washout periods: (a) PA32540 + clopidogrel (300 mg loading/75 mg maintenance) 10 hours later and (b) synchronous dosing of clopidogrel + EC aspirin (81 mg) + EC omeprazole (40 mg). The primary end point was the inhibition of platelet aggregation (20 μM adenosine diphosphate, maximal extent) after 7 days. CYP2C19 and ABCB1 genotypes were determined. Inhibition of platelet aggregation was greater with spaced PA32540 + clopidogrel therapy vs synchronous clopidogrel + EC aspirin + EC omeprazole therapy (P = .004). There was no difference in day 7 arachidonic acid-induced aggregation. The effect of spacing on pharmacodynamics was independent of genotype.

CONCLUSIONS

PA32540 and clopidogrel spaced 10 hours apart had greater antiplatelet effects than did synchronously administered EC aspirin (81 mg), clopidogrel (75 mg), and EC omeprazole in healthy volunteers. These finding are directly relevant to the treatment for patients with high gastrointestinal risk who require dual-antiplatelet therapy and gastroprotection.