BMJ: No evidence that
smoking
cessation
drug
linked to
increased risk of suicidal behaviour or traffic accidents.
Previous reports of a link may not have taken full account of
underlying risk factors, say researchers
There is no strong evidence that the popular smoking cessation
drug varenicline is associated with increased risks of suicidal
behaviours, criminal offending, transport accidents, traffic
-
related offences, and psychoses, finds a study in
The BMJ
this
week
.
The findings are based on over 69,000 individuals i
n Sweden
who were prescribed varenicline between 2006 and 2009.
Previous reports suggesting a link may not have taken full
account of underlying risk factors, say the authors.
Varenicline is widely prescribed for the treatment of nicotine
dependence, but
reports that it may be linked with increased
risks of suicidal behaviour, depression, psychoses and violence
have led regulatory agencies in Europe and the US to issue
warnings.
Varenicline use has also been restricted or prohibited for
several transportation industry professions, including pilots, air
traffic controllers, truck and bus drivers, and certain military
personnel, due to reports of increased traffic accidents.
However, these increased risks are based on post
-
marketing
surveillance and individual case reports, and are not consistent
with observational studies and trials that have found no
association between varenicline and depression, suicidality, or
violence.
To address these inconsistencies, researchers at the
Karolinska
Institutet
in Swede
n and
the University of Oxford in
the UK examined associations between varenicline and a range
of adverse outcomes in 69,757 individuals aged 15 and over
who were prescribed varenicline between 2006 and 2009.
They performed several analyses, adjusting for
known risk
factors such as age, sex and pre-existing psychiatric disorders,
and also studied rates of adverse events in the same individual
during periods of medication and non
-
medication, a novel
approach in this area.
National registers were used to
collate information on criminal
convictions, psychiatric conditions, suicidal behaviour, transport
accidents and traffic offences, and substance abuse.
The results show that varenicline was not associated with
significant increases in suicidal behaviour,
criminal offending,
transport accidents, traffic offences, or psychoses.
However, a small increased risk of mood and anxiety conditions
during periods of medication was found in individuals with pre
-
existing psychiatric disorders, which the authors say
“r
equires
confirmation
using other study designs.
”
The authors suggest that their findings may be generalizable to
other high income countries like the UK and USA due to similar
prescribing patterns and rates of these outcomes.
Although this is an obser
vational study so no definitive
conclusions can be drawn, the authors state that their results
“provide no evidence for a causal association between varenicline and criminal offending, transport accidents, traffic
offences, or psychoses.”