BMJ: There is insufficient evidence to show that using nicotine
patches for four weeks before a quit attempt (known as “preloading”)
improves long-term smoking abstinence, finds a trial published by The
BMJ this week. The researchers found that nicotine preloading reduces
craving intensity and seems to make quitting easier, but that this
beneficial effect may have been masked by a concurrent reduction in the
use of varenicline in the period after quit day. As varenicline is the
most effective smoking cessation drug, this may have undermined the
benefit of preloading.
If it were possible to overcome this unintended
consequence, nicotine preloading “could lead to a worthwhile increase in
long term smoking abstinence,” they say.
Although there have been several new drugs for tobacco
cessation since the 1970s, treatment has remained largely the same, with
behavioural support to motivate and strengthen a person’s resolve to
remain abstinent and drugs to reduce the strength of urges to smoke
after quit day.
Some studies have suggested that using nicotine replacement
therapy before a quit attempt is more effective than when used in the
conventional way to support abstinence, while other studies suggest
preloading has no effect.
A research team from the UK Centre for Tobacco and Alcohol
Studies, led by Professor Paul Aveyard at the University of Oxford, set
out to examine the effectiveness of a nicotine patch worn for four weeks
before a quit attempt.
Their trial involved 1,792 nicotine dependent adults from
four cities across England, who smoked an average of 19 cigarettes a
day. Most were middle aged and had lower levels of education than the UK
average, half were male and a quarter were from minority ethnic groups.
Smokers were randomly assigned to two groups – half
received standard smoking cessation drug therapy and behavioural
support, while the other half received the same treatment plus a daily
nicotine patch to use for four weeks before quit day.
After nicotine preloading had ended, smokers could opt to
continue to use either nicotine replacement therapy or non-nicotine drug
therapy.
At six months, 18% of participants who used nicotine
patches before their quit attempt had stopped smoking compared with 14%
who received standard therapy.
At 12 months, the differences between the two groups were
modest with 14% of participants achieving abstinence in the nicotine
preloading group compared with 11% who had received standard therapy.
Prolonged abstinence from smoking was confirmed using a carbon monoxide breath test.
Use of varenicline after quit day differed between arms
(22% in the preloading arm and 30% in the control arm). After
statistically controlling for this, there was clearer evidence that
preloading increased the likelihood of achieving abstinence (a 4%
difference between arms).
While there was no excess of serious adverse events in the
trial, around 1 in 20 people experienced minor adverse events caused by
nicotine preloading, such as nausea and headaches.
This trial has both strengths and limitations, say the
authors. For example, it was considerably larger than previous studies
on this topic, thus achieving good precision, and the ‘open-label’
design makes the results easier to apply to clinical practice.
However, this design can be seen as a limitation because
the participants know which treatment group they are in and this may
have affected their expectations of success.
“Evidence was insufficient to confidently show that
nicotine preloading increases subsequent smoking abstinence,” they
conclude. “The beneficial effect may have been masked by a concurrent
reduction in the use of varenicline in people using nicotine preloading,
and future studies should explore ways to mitigate this unintended
effect.”
[Ends]
Journal: The BMJ