Take personalised approach to antidepressants to minimise side effects

Guidelines should be updated to reflect differing physical side effects of antidepressants, and decisions about which drug to use should be made by the doctor and patient on an individual basis, UK researchers have concluded.

Researchers have for the first time put together a detailed comparison of the side effects associated with different antidepressants, highlighting a large variation in their impact on the body. Some antidepressants lead to substantial changes in weight, blood pressure and heart rate, the large analysis found.

The ranking of the side effects reported in The Lancet should encourage more personalised prescribing based on individual needs, the researchers from Kings College London said.

Related Article: Mythbuster: ‘Talking therapy is a waste of time, I need antidepressants’

To assess the differences, the team looked at data from 151 clinical trials and 17 US Food and Drug Administration (FDA) reports involving over 58,000 participants taking 30 different antidepressants.

They found marked variation including a 4 kg difference in weight change from an approximate 2.5 kg weight loss associated with agomelatine to a 2kg weight gain from maprotiline.

Overall, some antidepressants such as maprotiline and amitriptyline were associated with weight gain in almost half of individuals prescribed them, while others including agomelatine were associated with weight loss in 55% of patients.

For heart rate, the impact of the drugs varied by 20 beats-per-minute (BPM) from around an eight BPM decrease for fluvoxamine and a 14 BPM increase for nortriptyline.

When it came to blood pressure, the analysis showed a 10 mmHg variation from an approximate 7 mmHg decrease for nortriptyline to a 5 mmHg increase for doxepin.

They also reported that most antidepressants did not show major effects on kidney or liver function, electrolyte levels, or heart rhythm.

Related Article: Provide better physical health support with psychiatric medications

The side effects were assessed in the first eight weeks of taking the drugs and it is not known if they persist or change over time with more research is needed to understand how antidepressants affect the body over longer time periods, they explained.

Guidelines should reflect the differing physical side effects of antidepressants, they concluded.

Study leader Dr Toby Pillinger, consultant psychiatrist at the South London and Maudsley NHS Foundation Trust, said: ‘While many people benefit from antidepressants, these drugs are not identical – some can lead to meaningful changes in weight, heart rate, and blood pressure in a relatively short period.

‘Our findings show that SSRIs, which are the most prescribed type of antidepressant, tend to have fewer physical side effects, which is reassuring. But for others, closer physical health monitoring may be warranted.’

Related Article: CPD: Depression in adults – diagnosis and treatment in primary care

He added: ‘The aim isn’t to deter use, but to empower patients and clinicians to make informed choices and to encourage personalised care.’

This article was initially published by our sister publication Pulse