Doctors have long known that antidepressants can have side effects on cardiovascular and metabolic health.
But a major analysis by a team of UK researchers has, for the first time, compiled data from more than 150 clinical trials to compare the physical side effects of dozens of antidepressants.
The study, published in The Lancet this week, details how each medication can affect weight, blood pressure, heart rate, cholesterol, and other areas of health.
The end result is something like a “sports league table” for 30 different antidepressants, based on their side effect profiles, says lead author Dr. Toby Pillinger, a psychiatrist at King’s College London.
“This has never been done on this scale before, and no one has ever assigned specific numbers to the amount of weight you’ll gain or the increase in your cholesterol,” he says.
The findings are based on existing data, mainly from 8-week drug studies, which in total represent more than 58,000 patients.
The most commonly prescribed antidepressants in the US — selective serotonin reuptake inhibitors, or SSRIs, like Zoloft and Prozac — tend to have fewer physical side effects, according to the analysis.
Other medications, particularly some of the older ones, showed more significant impacts.
For example, a person taking nortriptyline, a tricyclic antidepressant, may, on average, have a heart rate increase 20 beats higher than the SSRI fluvoxamine. For other medications, the expected weight change can be 1.8 kg (4 pounds) gain or loss.
Pillinger says the intention is not to highlight certain antidepressants as better than others.
“It may be that a medication that’s really bad for one person is actually really good for another. I think that’s the message, rather than naming and shaming certain medications,” he says.
Pillinger hopes the data can help prescribers and their patients make individualized decisions about the best medication.
In fact, he and his colleagues have created a free digital tool that’s already being used by doctors worldwide to create a “menu” of options, based on the patient’s underlying health and the side effects they’d most like to avoid.
Dr. Nina Kraguljac, a professor at Ohio State University who was not involved in the research, says the study was well done — and largely reassuring.
“What surprised me about this study is that the side effects aren’t that severe,” says Kraguljac, who also chairs the Research Council of the American Psychiatric Association.
However, she emphasizes that “side effects alone should not guide a clinical decision,” since the study’s results ultimately reflect an average, not the individual patient.
“Side effects don’t occur in all patients and aren’t necessarily a reason to prevent people from taking the medications,” she says.
The study has some notable limitations.
Although many people take these medications for months or years, the data largely come from 8-week randomized clinical trials, which are the most common.
And some important side effects — that lead some people to stop taking antidepressants — were not assessed, says Dr. David Hellerstein, a professor of psychiatry at Columbia University.
He points out that impacts on sexual function, gastrointestinal problems, and “emotional blunting” — a feeling that emotions are being muted — are common complaints that weren’t analyzed.
Most of the side effects detailed in the study are already well known, though he believes the work will still be “a useful reference” for patients and prescribers.
“Overall, most of these medications seem quite safe on many physical parameters, especially the newer ones like SSRIs and SNRIs (serotonin-norepinephrine reuptake inhibitors),” he says.
But for some groups of people, side effects can be significant, he warns, “and may affect the doctor’s choice of medication or the patient’s preference”.
And, he notes, side effects aren’t always a disadvantage.
Hellerstein has a patient who had lost a significant amount of weight due to depression, meaning an antidepressant that also led to extra weight gain would actually be “healthy”.
“I would say that’s not a side effect. It’s a treatment benefit,” he says.
Source: npr.org by Will Stone