Effects of antidepressants on physical health ranked for first time

Side effects of different antidepressants have been ranked for the first time, revealing huge differences between drugs.

Academics looked at the impact medications had on patients in the first eight weeks after starting treatment, with some causing patients to gain up to 2kg in weight or vary heart rate by as much as 21 beats every minute.

Around eight million people in the UK take antidepressants.

Researchers warned the gulf in side effects could affect people's health and whether they could stick to their prescription.

They said nobody reading this should stop their treatment, but have called for antidepressants to be closely matched to the needs of each person.

Dr Toby Pillinger says: Sarah should have an antidepressant that avoids weight gain, such as agomelatine, sertraline or venlafaxine rather than amitriptyline or mirtazapine which are more likely to increase weight.

Dr Toby Pillinger says: John should avoid drugs such as venlafaxine, amitriptyline or nortriptyline which raise blood pressure, and would be better suited to citalopram, escitalopram and paroxetine.

Dr Toby Pillinger says: For Jane, some antidepressants are linked to higher cholesterol, including venlafaxine, duloxetine and paroxetine, so she might steer clear of those. Citalopram or escitalopram are more neutral on cholesterol and could suit her better.

It is too simplistic to say there are good and bad antidepressants, the researchers say. Even though amitriptyline increases weight, heart rate and blood pressure it also helps with pain and struggling to sleep.

Overall, the most prescribed class of antidepressants - SSRIs such as paroxetine, citalopram, escitalopram and sertraline - tended to have fewer physical side effects.

Fluoxetine - an SSRI that is also called Prozac - was linked to a drop in weight and higher blood pressure, in the study.

Prof Andrea Cipriani from the University of Oxford said it was "impossible" to say how many of the millions of people being prescribed antidepressants should be on a different drug.

However, he said there had been a push for "generic, cheap medications" that meant 85% of antidepressant prescriptions in the UK were for just three drugs: the SSRIs citalopram, sertraline and fluoxetine.

He said implementing the findings of this report would see "the 85% reduce dramatically" with "more people accessing better treatments".

The researchers are developing a free online tool to help doctors and patients choose the right drug.

However, that would still require a significant change in culture within the NHS.

The study also only analysed what happened eight weeks after starting treatment. Dr Pillinger said "complimentary data" meant they expected the short-term changes "will persist" but this still needs to be properly tested.

Dr Prasad Nishtala, from the University of Bath which was not involved in the study, said the findings were "novel and valuable".

He said: "In a real-world setting, where patients often receive antidepressants for months or years, the cumulative risks are likely to be higher, particularly among those with chronic depression."