For all those taking medication for heart problems, a study recently showed that common medicines used to treat high blood pressure and angina (chest pain) is linked to a high risk of out-of-hospital sudden cardiac arrest.
Sudden cardiac arrest is the number one cause of about half of the cardiac deaths in Europe and one in five natural deaths. The condition where the heart stops pumping blood, after a cardiac arrhythmia, it can become lethal in minutes if untreated.
The European Sudden Cardiac Arrest network (ESCAPE-NET) presented the results of the study which was was set up to find the causes of arrhythmias so that it could be prevented. Dr Hanno Tan, ESCAPE-NET project leader and cardiologist, Academic Medical Centre, Amsterdam, Netherlands, urged caution when interpreting these results. He said, “The findings need to be replicated in other studies before action could be taken by doctors or patients.”
The study examined if nifedipine and amlodipine, dihydropyridines widely used for high blood pressure and angina, are linked with out-of-hospital cardiac arrest. The nifedipine doses most often used and studied in this investigation are 30 mg and 60 mg (90 mg is available but infrequently used) and the amlodipine doses are 5 mg and 10 mg. Standard practice is to start with a lower dose, then give a higher dose if blood pressure or chest pain are not sufficiently reduced.
Current use of high-dose (>60 mg/day), but not low-dose (<60 mg/day), nifedipine was significantly associated with an increased risk of out-of-hospital cardiac arrest compared to non-use of dihydropyridines, with an odds ratio of 1.5 in ARREST and 2.0 in DANCAR. High-dose nifedipine was also associated with an increased risk of out-of-hospital cardiac arrest when compared with any dose of amlodipine, with odds ratios of 2.3 and 2.2 in the ARREST and DANCAR registries, respectively. There was no risk associated with amlodipine.
These findings may be surprising given that both drugs have been in use for many years and in many patients.