Since AZCERT's initial launch in 1999, it has advanced educational and research efforts by developing resources for medical professionals, researchers and consumers. AZCERT has developed and applied a systems-based approach to reduce harm from medications and drug-drug interactions (DDIs) with a special focus on drugs that prolong the QT interval and cause sudden death. AZCERT's risk-stratification process includes monitoring of scientific articles in the published medical literature, information in the official drug label, reports submitted to its website and data in the FDA's Adverse Event Reporting System (AERS) using Oracle's Empirica software. Using this process, AZCERT maintains lists of drugs at www.CredibleMeds.org that cause QT prolongation and TdP. Educational programs are conducted to reduce prescribing and administration of drugs that can cause harm to patients. AZCERT's process for adverse drug event causality analysis (ADECA) assesses the relative risk of drugs that cause TdP and is described here. Four categories of risk are specified to place drugs into different lists. ‘Drugs with risk’ have a well-established risk of TdP when taken at recommended dosages. ‘Conditional risk’ applies to drugs for which their TdP risk depends on specific conditions, such as overdose or drug-drug interactions (DDIs). Drugs that are kown to prolong QT, but do not meet the evidence requirements for TdP causality are classified as having a ‘possible risk’ of TdP. The drugs on these three lists are combined and certain cardiac stimulant drugs are added to create a fourth list of drugs that should be avoided, if at all possible, in patients with the inherited long QT syndrome, a rare but potentially lethal disorder. Medications on all four lists and others that come under review are continuously monitored for emerging evidence and the lists are updated approximately every 30 days. The web-based drug lists receive approximately 70,000 unique visitors from over 60 countries each month and the website serves as a unique global resource that is highly valued for its positive impact on clinical prescribing. A major hospital system, the Mayo Clinic in Rochester, MN has incorporated the CredibleMeds drug list into an electronic prescribing alert system to identify patients at risk for sudden death. The lists of drugs have also been a valuable resource for clinical investigations and for drug regulators. extracted a list of non-cardiac drugs that prolong QT from the CredibleMeds.org website in order to examine all-cause mortality in a population-based, case–control study. They found an approximately threefold greater risk of death (95% CI 1.6–4.7) among patients who had been treated with the non-cardiac, QT-prolonging drugs listed in the CredibleMeds.org database. On the basis of this analysis, the investigators estimated that the use of these drugs causes >15,000 deaths annually in the USA and Europe. More recently, van der Sijs and colleagues investigated whether physicians who had prescribed two drugs from the CredibleMeds.org lists and then ignored a DDI alert for QT prolongation subsequently ordered an ECG for the patient. The researchers found that 33% of patients did not have an ECG; however excessive QT prolongation (>75 ms increase) was seen in 31% of those who did have an ECG. cite the importance of the CredibleMeds.org lists for their drug safety programme and pharmacovigilance efforts. The Medical Letter and international regulatory agencies cite the drug lists as resources when evaluating the safe use of medicines. For example, New Zealand’s federal Medicines Safety Authority cites the QTdrugs.org lists on CredibleMeds.org as resources for the Authority’s evaluation of the safety of antidepressants that prolong the QT interval. CredibleMeds is maintained by its founder, Dr. Raymond Woosley, and an all volunteer team of scientists and communication specialists. A management team is developing a financial plan for sustainable funding from charitable contributions, subscriptions and grants. Expansion of the current focus on drug-induced arrhythmias will include lists of drugs that cause liver or kidney injury. The long range goal for the organization is to develop partnerships in order to incorporate the drug lists generated by CredibleMeds into clinical decision support systems that save lives.
