Older people taking new generation antidepressants are at greater risk of suffering from falls and fractures, among other serious conditions such as stroke and epilepsy, according to researchers at The University of Nottingham.
Depression is a common condition in older people and antidepressants, particularly new generation selective serotonin reuptake inhibitors (SSRIs), are widely used. However, little is known about the safety of these drugs in older people, researchers said.
“We've found some evidence from our study that the older tricyclic antidepressants may be associated with lower risks of several adverse outcomes compared with newer antidepressants in older people diagnosed as having depression,” researchers said.
“This was an unexpected finding,” they continued, “and so further research using other data sources is needed to confirm these findings as well as provide more evidence on the benefits of different antidepressants in this group of people."
Researchers identified 60,746 UK patients aged 65 and over with a newly diagnosed episode of depression between 1996 and 2007. Many patients had other conditions, such as heart disease and diabetes, and were taking several medications.
Patients were tracked until the end of 2008. During this time, 89 percent received at least one prescription for an antidepressant, and almost 1.4 million prescriptions for antidepressants were received. Of these, 57 percent were for SSRIs, 31 percent for tricyclic antidepressants and 14 percent for other antidepressants.
Antidepressant use was then analysed against several adverse outcomes including all-cause mortality, attempted suicide or self harm, heart attack, stroke, falls, fractures, epilepsy or seizures and high salt levels in the blood (hyponatraemia).
After adjusting for factors that could affect the results, including age, sex, severity of depression, other illnesses and use of other medications, the team found that SSRIs and drugs in the group of other antidepressants were associated with an increased risk of several adverse outcomes compared with tricyclic antidepressants.
Those taking SSRIs were more likely to die, suffer a stroke, fall or fracture, have epilepsy or a seizure and have hyponatraemia. The group of other antidepressants were associated with an increased risk of mortality, attempted suicide or self-harm, stroke, fracture and epilepsy or seizures.
Among individual drugs trazodone, mirtazapine and venlafaxine carried the highest risk for some adverse outcomes, according to researchers. Rates of most adverse outcomes were highest in the 28 days after starting the antidepressant and also in the 28 days after stopping.
Researchers cautioned that differences between patients prescribed different antidepressant drugs may account for some of the associations seen in the study, underlining the need for further research to confirm the findings.