People taking certain types of antidepressants may gain up to 2 kg (4.5 lb) in weight during the first two months of treatment, while patients taking other drugs may lose the equivalent or more, according to an extensive review of potential side effects.
The study, conducted by researchers from King's College London and the University of Oxford, found that while some antidepressants can cause noticeable changes in body weight, heart rate and blood pressure, others do not cause such physical changes.
The researchers are calling for an update to antidepressant treatment guidelines to reflect these findings.
Antidepressants are medications that can help with mental health conditions such as depression and anxiety and are recommended to be taken for two years in most cases.
The study included an analysis of data from 151 clinical trials of antidepressants that compared the physical health effects of 30 different antidepressants in more than 58,000 people.
The researchers found marked differences in side effects between the different medications, even though most of the studies analyzed included only eight weeks of antidepressant use.
For example, the difference in average weight change between some drugs was up to 4 kg: this is equivalent to a weight loss of approximately 2.5 kg with agomelatine compared with a weight gain of approximately 2 kg with maprotiline. Weight gain occurred in nearly half of people prescribed drugs such as maprotiline or amitriptyline, while more than half of those taking agomelatine experienced weight loss.
The study also found a 21 beats per minute difference in heart rate between people taking fluvoxamine and nortriptyline. A blood pressure difference of 11 mmHg was found between nortriptyline and doxepin. Art.
Dr Toby Pillinger, clinical lecturer at KCL, said: “Antidepressants are some of the most widely used medicines in the world. Although many people benefit from them, the drugs are not identical – some can cause significant changes in weight, heart rate and blood pressure over a relatively short period of time.”
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“Our results show that SSRIs [selective serotonin reuptake inhibitors]which are the most prescribed type of antidepressants tend to have fewer physical side effects, which is encouraging. But for others, more careful monitoring of physical health may be warranted. The goal is not to discourage use, but to empower patients and physicians to make informed choices and encourage personalized care.”
Andrea Cipriani, professor of psychiatry at the University of Oxford, said: “Our findings highlight the importance of shared decision-making, a collaborative process through which doctors support patients in making decisions about their treatment by bringing together their preferences, personal circumstances, goals, values and beliefs. This should be the way forward in the NHS and around the world.”
