People who use older generation antidepressant drugs may be at an increased risk of developing heart disease, the results of a new study indicate.
However, there is no increased heart risk associated with newer antidepressants, such as SSRIs (selective serotonin re-uptake inhibitors). SSRIs, which include Prozac and Seroxat, are the most commonly used type of antidepressants.
UK researchers followed the progress of almost 15,000 people over the age of 35. Anyone with a history of confirmed heart disease was excluded.
Participants were asked a range of questions on demographics and lifestyle, such as smoking, alcohol intake and physical activity.
The researchers also assessed psychological distress using a questionnaire that enquired about symptoms of anxiety and depression in the last four weeks. In a separate visit, nurses collected information on medical history, including psychiatric hospital admissions, and medication, and took blood pressure readings.
During an average of eight years follow-up, there were 1,434 heart disease-related events, of which one in four were fatal. Of the study participants, 2.2%, 2% and 0.7% reported taking tricyclic antidepressants, SSRIs or other antidepressants respectively.
After adjusting for various confounding factors, including indicators of mental illness, the researchers found there was a 35% increased risk of heart disease associated with tricyclic antidepressants. The use of SSRIs was not associated with any increased risk, nor did the researchers find any significant associations between antidepressant use and deaths from any cause.
"Our findings suggest that there is an association between the use of tricyclic antidepressants and an increased risk of cardiovascular disease (CVD) that is not explained by existing mental illness. This suggests that there may be some characteristic of tricyclics that is raising the risk. Tricyclics are known to have a number of side-effects - they are linked to increased blood pressure, weight gain and diabetes and these are all risk factors for CVD," explained lead researcher, Dr Mark Hamer of University College London.
He emphasised that patients who are already taking antidepressants should not cease taking their medication suddenly, but should consult their GPs if they are worried.
"There are two important points to be made. First, tricyclics are the older generation of antidepressant medicines and we found no excess risk with the newer drugs (SSRIs).
Secondly, people taking the antidepressants are also more likely to smoke, be overweight, and do little or no physical activity. By giving up smoking, losing weight, and becoming more active, a person can reduce their risk of CVD by two to three-fold, which largely outweighs the risks of taking the medications in the first place. In addition, physical exercise and weight loss can improve symptoms of depression and anxiety," Dr Hamer said.
He pointed out that the majority of previous work in this area has focused on patients who already had heart problems, however this one looked at a healthy population.
"Given that antidepressants, such as SSRIs, are now prescribed not only for depression, but for a wide range of conditions such as back pain, headache, anxiety and sleeping problems, the risks associated with antidepressants have increasing relevance to the general population," Dr Hamer added.
Details of these findings are published in the European Heart Journal.
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