Little is known about the effects of antidepressants on health issues such as insomnia and migraine. Yet they’re still prescribed by some doctors to treat these conditions.
A new study found that around a third of antidepressants are prescribed for “off-label” use (aka not for its intended purpose).
Off the back of this, experts have argued that there’s a lack of scientific evidence to suggest antidepressants effectively treat alternate health complaints such as PMT, insomnia and nerve pain.
In light of the study’s findings, a UK-based GP said that while they highlight a need for more research in this area, in many cases, doctors simply have to weigh up the risk versus benefit of an individual taking medication and then act accordingly.
Antidepressant use has increased substantially in the UK and in other western countries such as Canada and the USA.
The number of antidepressants dispensed in England increased by 3.9 million (6.8%) between 2014 and 2015 - more than any other class of prescription drugs.
A team of researchers decided to examine off-label prescriptions for antidepressants and assess the level of scientific support for them.
The term “off-label” refers to when a drug is prescribed for a different condition, given to a different patient group (e.g. children) or in a different dose or formulation than in the approved label.
Using data from an electronic prescribing system, they tracked over 100,000 antidepressant prescriptions written by 174 doctors for over 20,000 adults between 1 January 2003 and 30 September 2015 in Quebec, Canada.
Tricyclic antidepressants (TCAs) had the highest prevalence of off-label indications and were commonly used for treating insomnia.
Meanwhile 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 16% were directly supported by strong scientific evidence backing the drug’s use for the health issue.
For 40% of off-label prescriptions, there was no strong evidence backing the drug’s use for the illness, but there was strong evidence for another drug in the same class.
For the remaining 44% of off-label prescriptions, neither the prescribed drug nor any other drugs in the class had strong evidence for the indication.
Researchers said the results “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”.
In a linked editorial, researchers at the University of Dundee said research shows that off-label prescribing is common and often poorly supported by evidence.
They recommended that, for all prescribing, patients should be given enough information to allow them to make an informed decision to take a medicine (or not).
In response to the findings, Dr Helen Webberley, GP for Oxford Online Pharmacy, told The Huffington Post UK: “It’s not unusual to use off-label antidepressants in the UK, we often use amitryptiline for nerve pain and SSRI antidepressants to treat PMT for example, both are extremely effective, though untested in this indication.
“The GMC guidelines suggest the prescription of unlicensed medicines when clinically appropriate, for example if there is no suitable licensed treatment available, or if the licensed treatment is temporarily unavailable.
“GPs are advised to weigh up all of the options when choosing to prescribe an off license medication and to base decisions on past experience of the medicine’s safety and efficacy, which in some cases may be limited.
“Studies such as this are essential in highlighting the fact that more research is needed. Though in many cases, it is a balance of risk versus benefit that dictates the course of action taken by the GP.”