People prescribed different antidepressants can experience significantly different side-effects, including weight changes, heart rate shifts, and blood pressure variations, according to new UK research.
The large-scale review, led by King’s College London and the University of Oxford, analysed data from 151 clinical studies involving more than 58,000 participants. It compared the physical effects of 30 antidepressants, revealing notable variations between drugs.
For example, patients taking maprotiline gained about 2kg on average within eight weeks, while those on agomelatine lost around 2.5kg. Nearly half of those on maprotiline or amitriptyline experienced weight gain, whereas more than half on agomelatine lost weight.
The study also identified a 21-beat-per-minute difference in heart rate between people taking fluvoxamine and nortriptyline, and an 11 mmHg difference in blood pressure between nortriptyline and doxepin.
Dr Toby Pillinger from KCL said that while antidepressants benefit many people, the drugs “are not identical,” urging for treatment guidelines to reflect their differing physical effects. He noted that SSRIs — the most commonly prescribed class — tend to cause fewer physical side-effects, but other types may require closer monitoring.
Prof Andrea Cipriani of Oxford added that the findings highlight the need for “shared decision making” between patients and clinicians, ensuring treatment choices reflect individual health profiles, preferences, and values.
