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GPs warned off-label antidepressant prescribing ‘lacks evidence’



Researchers have urged GPs to be cautious about prescribing off-label antidepressants, after a study found nearly half of drugs prescribed off-label did not have any clear evidence to support their use

The study of 174 primary care doctors in Canada showed that around a third of all prescriptions for antidepressants over a 12-year period were off-label.

Of these, 45% lacked strong scientific evidence to support their use for the indication they were prescribed for, with trazodone for insomnia being the most frequently prescribed drug with no supporting evidence.

Just 16% of prescriptions were backed up by scientific evidence, including amitriptyline for pain, escitalopram for panic disorders and venlafaxine for obsessive compulsive disorders.

Around 40% of prescriptions had evidence to support the off-label prescription of another drug in the same class.

The researchers said the vast number of available drugs can make it difficult GPs to remember which drugs are appropriate for which indications, but also that contraindications and a lack of effective treatments for symptom-based conditions could mean they are turning to off-label antidepressants as a last resort.

‘When evidence to support efficacy is lacking, physicians should exercise caution, prescribe conservatively, and inform patients of this information via a shared decision making process,’ the researchers said.

‘These findings highlight an urgent need to produce more evidence on the risks and benefits of off-label antidepressant use and to provide physicians with this evidence at the point of prescribing.’

Writing in a linked editorial, Professor Bruce Guthrie, professor of primary care, and Dr Daniel Morales, GP and discovery fellow, both from the University of Dundee, said ‘off-label prescribing is common and is often poorly supported by evidence or relies heavily on extrapolating evidence from one situation to another’.

But they also highlighted that ‘these pitfalls are not confined to off-label drugs’ and cautioned that ‘patients and prescribers should be cautious about all extrapolations of evidence whether the proposed treatment is “on-label” or “off-label”.’

They noted that the UK GMC says GPs must be able to justify their decisions on prescribing drugs ‘regardless of whether they are licensed or unlicensed’.

BMJ 2017; available online 21 February