Fears over the use of antidepressants for other illnesses
Doctors and patients need more information on the risks and benefits of antidepressants for 'off-label' use, a new study warns today.
Off-label use occurs when a drug is prescribed for a different condition, given to a separate patient group, or in a different dose or formulation than on the approved label.
Antidepressant use has increased substantially in Ireland and other western countries. Around 2.5 million prescriptions for the drugs are now written in this country annually.
The study by researchers in McGill University, Montreal, Canada, found a third of antidepressants are prescribed for "off-label" conditions, most commonly pain, insomnia and migraine.
But it is unknown to what extent these prescriptions are supported by scientific evidence, the 'British Medical Journal' reported.
Using data from an electronic prescribing system, they tracked more than 100,000 antidepressant prescriptions written by 174 primary care physicians for more than 20,000 adults between January 1, 2003, and September 30, 2015.
Overall, 29pc of all antidepressant prescriptions were written for an off-label illness. Tricyclic antidepressants (TCAs) had the highest prevalence of use for off-label illness, while selective serotonin reuptake inhibitors (SSRIs) and serotonin-noradrenaline reuptake inhibitors (SNRIs) were less likely to be prescribed off-label.
Among all off-label antidepressant prescriptions only 16pc - 4,977 out of 31,319 - were directly supported by strong scientific evidence backing the drug's use for the condition.
For 40pc, there was no strong evidence backing the drug's use for the illness.
For the remaining 44pc of off-label prescriptions, neither the prescribed drug nor any other drugs in the class had strong evidence for the complaint.
Commenting on the study, Darragh O'Loughlin of the Irish Pharmacy Union said the extent of off-label prescribing was unknown in Ireland.
Pharmacists are not told if a medicine is used off-label and not informed on the prescription what condition the drugs are being prescribed for.
Doctors normally used off-label prescribing with the best of intentions after other treatments had failed, he pointed out.
"There is nothing intrinsically wrong using an off-label drug as long as doctors are using their best clinical judgment," he said.