MEDIA BRIEFING
23rd August 2005
Study shows aspirin and paracetamol reduce fever equally well
There is no significant difference in efficacy between
aspirin and paracetamol when they are used to treat fever and
other symptoms associated with viral upper respiratory tract infection
(URTI), according to a large international study(1).
This new, randomised, double-blind, placebo-controlled trial shows
that, at single doses of 500 and 1,000 mg, both aspirin and paracetamol
significantly reduce fever, headache and other symptoms in adults
with URTI with a similar frequency of adverse events.
The efficacy of aspirin and paracetamol was so impressive that
the study was ended prematurely because it was considered unethical
to deny such effective treatment to participants by giving them
a placebo.
This study clearly demonstrates that aspirin is highly effective
in relieving fever and other symptoms of URTI in adults, and that
it is well tolerated.
Why was the study carried out?
Aspirin and paracetamol are familiar household medicines
for the treatment of colds and minor pains but there are few scientific
comparisons of their effectiveness and tolerability. There is
a misconception that paracetamol is better at reducing fever and
has fewer side effects than aspirin, and that aspirin is a superior
analgesic. This study was conducted to provide scientific evidence
of the comparative efficacy and tolerability of these medicines
in relieving the common symptoms of viral URTI.
Who were the participants?
The participants were chosen to be representative of
people with a common cold. They were men and women aged between
18 and 65 who had a URTI and fever probably caused by a virus
and lasting for no more than 5 days. Their symptoms included headache,
aching, sore throat, cough, runny nose, chills and sweating. People
were excluded if they had more serious illness (such as bacterial
sinusitis or pneumonia) or were taking other medicines that might
affect their symptoms.
How was the study carried out?
392 participants were randomly assigned to one of the
treatments or placebo. Neither they nor the investigators were
aware of which intervention they took. The interventions were
single doses of placebo, aspirin 500 or 1,000 mg, or paracetamol
500 or 1,000 mg.
The main endpoint of the study was the total change in
fever over the first 4 hours following the dose. Other endpoints
included the extent and timing of fever relief and the severity
of other symptoms. Fever was measured every 30 minutes for 6 hours.
Participants noted the severity of other symptoms at 2, 4 and
6 hours. Adverse events were recorded throughout the study.
What was the main finding?
Both doses of aspirin and paracetamol reduced fever more
than placebo and these differences were statistically significant.
There was no difference between similar doses of aspirin and paracetamol.
What were the other findings?
The reduction in fever began 30 minutes after the dose and persisted
for at least 6 hours for both doses of aspirin and paracetamol.
The higher doses of each medicine achieved greater reductions
in fever than the lower doses. Aspirin 1,000 mg reached its peak
effect on fever (lowered by 1.67°C) more quickly than paracetamol
1000 mg (lowered by 1.71°C) (time to maximum temperature difference
174 vs. 213 minutes).
Both doses of aspirin and paracetamol reduced headache severity
throughout the study. Achiness and feverish discomfort were reduced
at all time points for the higher doses of both aspirin and paracetamol.
Neither medicine relieved sinus sensitivity and only aspirin 1,000
mg reduced the pain of sore throat. During the study, half of
participants assigned to placebo took 'rescue' medicine to relieve
their symptoms compared with only 5% who took aspirin or paracetamol
1,000 mg.
Tolerability
All treatments were well tolerated and all adverse events
were of mild to moderate intensity.
The overall frequency of adverse events in those who took placebo
was 21.8%; this compared with 15.4% for aspirin 500 mg and 12.7%
for paracetamol 500 mg, and 30.8% for aspirin 1,000 mg and 29.1%
for paracetamol 1,000 mg. These differences were not statistically
significant.
The frequency of adverse events that investigators believed could
be attributed to treatment was 5.1% with placebo, 10.3% for aspirin
500 mg, 11.4% for paracetamol 500 mg, 29.5% for aspirin 1,000
mg and 25.3% for paracetamol 1,000 mg. The differences between
the higher doses of each drug and placebo were statistically significant.
Adverse events included increased sweating and gastrointestinal
events but these were not significantly more common with either
drug than with placebo.
What does this study tell us?
Aspirin and paracetamol are both effective treatments
for fever and they also relieve other symptoms of viral URTI such
as headache. In both cases, a dose of 1,000 mg is more effective
than a dose of 500 mg. These medicines act quickly (within 30
minutes) and their effects last for at least 6 hours.
There is no difference in tolerability between aspirin and paracetamol.
Both treatments are well tolerated and adverse events of mild
to moderate intensity are more frequent with the higher doses
of each drug than with placebo.
- ENDS -
Reference
1. Bachert C, Chuchalin AG, Eisebitt R, Netayzhenko VZ,
Voelker M. Aspirin compared with acetaminophen in the treatment
of fever and other symptoms of upper respiratory tract infection
in adults: a multicentre, randomized, double-blind, double-dummy,
placebo-controlled, parallel-group, single-dose, 6-hour dose-ranging
study. Clin Ther 2005;27:993-1003
