Published today on bmj.com a new study discovered, the new generation antidepressants, selective serotonin reuptake inhibitors (SSRIs) are linked with an incremental risk of various severe adverse outcomes in older individuals in comparison with older tricyclic antidepressants (TCAs)
When prescribing drugs to older people, the risks and benefits of different antidepressants should be carefully assessed, the authors said.
Antidepressants, particularly SSRIs, are used by many older people, where depression is a common condition. However little is known about the safety of these drugs.
Researchers from the Universities of Nottingham and East Anglia, investigated the association between antidepressant treatment and the risk of various potential life threatening outcomes in older people.
Between 1996 and 2007, researchers identified 60,746 UK patients aged 65 and over with a newly diagnosed depression. Many also had other conditions, such as heart disease and diabetes while also taking multiple medications.
Patients were monitored until the end of 2008. During which 54,038 (89%) received a minimum of one prescription for an antidepressant, out of the prescriptions 55% were for SSRIs, 32% for TCAs, 0.2% for monoamine oxidase inhibitors (MAOIs), and 13.5% for other antidepressants.
The use of antidepressants was analyzed against various detrimental outcomes including, all-cause mortality, attempted self harm or suicide, heart attack, stroke, falls, fractures, epilepsy or seizures, and hyponatraemia (high salt levels in the blood).
Accommodating for factors which could influence the results, such as sex, severity of depression, other illnesses and use of other medications, they found that compared to TCAs, SSRIs and drugs in the association of other antidepressants were linked with an increased risk or several adverse outcomes.
In comparison to TCAs, SSRIs were connected with a higher risk of all-cause mortality, stroke, falls, fracture, epilepsy or seizures, and hyponatraemia. The other group of antidepressants were connected with a higher risk of all-cause mortality, attempted suicide or self harm, stroke, fracture, and epilepsy or seizures.
Patients who were depressed but not taking antidepressants had a 7% risk of dying (absolute risk of all-cause mortality) some time within the next year. Similar risks were 8.1% for patients taking TCAs, 10.6% for SSRIs, and 11.4% for the other group of antidepressants. Stroke risks for one year were 2.3%, 2.6% and 3.0% in comparison to 2.2% for the patients not on antidepressants, and the risk for fractures were 2.2%, 2.7%, and 2.8% in comparison to 1.8%.
Trazodone, mirtazapine, venlafaxine in addition with individual drugs were connected with the highest risks for several outcomes.
In the first 28 days of starting an antidepressant, and the first 28 days after stopping the outcome rates were highest.
TCAs were prescribed at lower doses than SSRIs and other antidepressants, which the authors say “could in part explain our findings.” Warning that differences between patients being prescribed different antidepressant medication, could possibly account for some of the connections seen in the study and suggest further research is needed to validate these findings.
They concluded that the risks and benefits of different antidepressants should be strategically evaluated when prescribing these drugs.
Professor Ian Hickie from the University of Sydney says in an accompanying editorial that, despite some limitations,
“the study has clear implications for more informed prescribing and enhanced clinical monitoring. Given the potential harms, the decision to prescribe for an older person with depression should not be taken lightly.”
Written by Grace Rattue