Public Health Outcomes May Differ After Switching from Brand-Name to Generic Angiotensin II Receptor Blockers

Generic substitution of amlodipine is not associated with increased risk of mortality or adverse cardiovascular events: An observational cohort study

This study aims to assess clinical outcomes following switching from originator to generic amlodipine. This population-based, matched, cohort study included users of originator amlodipine using claims data during 2018-2020 from a health system in Tianjin, China, in which usage of generic amlodipine was promoted by a drug procurement policy, the national volume-based procurement. Non-switchers refer to those remained on originator after the policy, while pure-switchers were those who switched to and continued using generic amlodipine, and back-switchers were those switched to generic amlodipine but then back to the originator. Propensity score matching generates comparable non-switchers and pure-switchers pairs, and non-switchers and back-switchers pairs. The primary outcome was major adverse cardiovascular events (MACEs), defined as all-cause mortality, stroke, and myocardial infarction during follow-up (April 1, 2019 to December 30, 2020). Secondary outcomes included heart failure, atrial fibrillation, and adherence to amlodipine. The hazard ratio (HR) for each clinical outcome was assessed through Cox proportional hazard regression. In total, 5943 non-switchers, 2949 pure-switchers, and 3061 back-switchers were included (mean age: 62.9 years; 55.5% men). For the matched pairs, pure-switchers (N = 2180) presented no additional risks of clinical outcomes compared to non-switchers (N = 4360) (e.g., MACEs: 2.86 vs. 2.95 events per 100 person-years; HR = 0.97 [95%CI: 0.70-1.33]). Back-switchers (N = 1998) also presented no additional risk compared to non-switchers (N = 3996) for most outcomes except for stroke (HR = 1.55 [95%CI: 1.03-2.34]). Pure-switchers and back-switchers all had better amlodipine adherence than non-switchers. Generic substitution of amlodipine is not associated with increased risk of cardiovascular events or all-cause mortality, but improves medicine adherence.

Clinical equivalence of generic and brand-name drugs used in cardiology: what do we know?

The problem of using generics in the treatment of patients with cardiovascular diseases remains relevant for more than a decade. The concern of doctors, pharmacists and patients is not diminishing with the constant rise in cardiovascular morbidity and mortality worldwide. Based on a systematic review of 186 publications, physicians identified concerns about the quality, reliability and replaceability of original drugs; pharmacists have shown the highest level of generic approval. Patients distrust of generics was revealed, caused by a lack of information, concerns about packaging, and negative experience of replacing the original drug. Three meta-analyzes compared generic and original drugs of cardiovascular groups in terms of efficacy and safety. A 2008 meta-analysis (47 studies, 9 classes of cardiovascular drugs) assessed the effect on mild outcomes, a 2016 meta-analysis (74 studies, 7 classes of drugs) also assessed side effects. The cumulative effect revealed a small and nonsignificant difference, which indicated that there was no superiority of original drugs over generics; there were no differences in the frequency and severity of side effects between generics and original drugs. A 2020 meta-analysis (72 studies, 9 drug classes) assessed the frequency of hospital admissions (including emergency department consultations, hospitalizations) and found a significant increase in the risk for generics for any reason (14%), but not for cardiac vascular diseases. A review of 8 cohort studies evaluating antihypertensive drugs for long-term cardiovascular outcomes, duration of retention, and substitution effect did not find significant differences between generics and brands. In a systematic review of studies comparing warfarin and generics, there were no significant differences in international normalized ratio and the incidence of thromboembolic and hemorrhagic complications; however, in one study, the frequency of hospital visits was 10% higher for generics. A systematic review of studies comparing clopidogrel versus generics shows drug comparability for major cardiovascular events and mortality. A review of 5 cohort studies evaluating originator statins and generics showed comparable rates of all-cause mortality and major cardiovascular events, except for one study with conflicting results. Meta-analyzes and large observational studies indicate that generics are not the worst efficacy, sometimes even surpass that of original drugs and can be justifiably used in clinical practice.