Download Dr. Sitar's presentation

Daniel S. Sitar, BScPharm, PhD, FCP
Professor Emeritus
University of Manitoba
May 3, 2010
OBJECTIVES
y The
will
know th
the d
drugs
Th audience
di
ill k
available without prescription to
manage modest pain conditions
y The
Th audience
di
will
ill understand
d
t d th
the
differences among them that may
affect choice
y The
Th audience
di
will
ill k
know which
hi h
preparations they should not use
y The audience will be aware of the fact
th t brand
that
b
d name d
drugs are nott always
l
the same when purchased in Canada vs
the USA
OVER-THE-COUNTER DRUGS
y Acetylsalicylic acid
y (Aspirin in many other countries)
y Acetaminophen
y (Paracetamol in the UK)
y Ibuprofen
y Naproxen
y Combination products
ANALGESIC PROPERTIES
All of these over-the-counter
drug preparations are analgesic,
anti-inflammatory and antipyretic
EXCEPT
Acetaminophen
PAIN MANAGEMENT
Health and Welfare Canada 1984
DOSE INGESTION PRINCIPLE
y The faster you can get the drug into the
intestines the more rapid will be the
onsett off analgesic
l
i efficacy
ffi
y Cold
C ld solutions
l ti
accelerate
l
t gastric
t i emptying
t i
y Absorption with an empty stomach will
provide the fastest onset of analgesia
ACETYLSALICYLIC ACID
Plain vs. Enteric-Coated Acetylsalicylic Acid
Biopharm Drug Disposit 1986;7:21
SALICYLATE INGESTION ISSUES
y Take with a glass of cold water
y (6 – 8 oz)
y For recurrent pain,
pain a single starting
dose of 650 mg should be the minimum
ingestion
y Do not take enteric-coated salicylate
for acute pain conditions
y A dose of 975 mg every 12 hours is a
reasonable dose strategy to treat
chronic pain that is responsive to
acetylsalicylic acid
NEW EVIDENCE FOR
SALICYLATE EFFICACY
y A single 1000-mg dose of aspirin is an
effective treatment of acute migraine
headaches for more than half of people
who take it
y Compared
C
d with
ith placebo,
l
b aspirin
i i
reduced associated symptoms of
nausea vomiting,
nausea,
vomiting photophobia
photophobia, and
phonophobia
Cochrane Database Syst Rev. Posted online April 14, 2010.
ACETAMINOPHEN
Lack of acetaminophen ceiling effect
on RIII nociceptive flexion reflex
(Eur J Clin Pharm 1998)
AU
UC of Analg
gesic Effecct
30
25
20
15
10
5
0
Placebo
500 mg
1000mg
Acetaminophen Dose (i.v.)
2000mg
ACETAMINOPHEN INGESTION
ISSUES
y A dose of 500 mg should be the lowest
ingested. No more than 1000 mg should
be ingested at any one time.
time
y Ingest with 6 – 8 oz of cold water
y For chronic pain, dose ingestion should
be repeated every 6 hours
y In contrast to salicylate,
y
, efficacy
y is not
significantly prolonged by increasing
the dose
IBUPROFEN
IBUPROFEN DOSE ISSUES
y The starting dose should be 200 – 400
mg every 4 – 6 hours, but no more than
1200 mg/day
/d
y Only half of the dose contains active
drug
y Take with a glass of cold water
(6 – 8 oz))
y Less effective for pain states that do
nott have
h
an iinflammatory
fl
t
componentt
NAPROXEN
NAPROXEN DOSE ISSUES
y This drug has only recently become
available without a prescription in
Canada
y Do not take more than one tablet every
12 hours without consulting
g a physician
p y
y Take with a glass of cold water
((6 – 8 oz))
y In contrast to ibuprofen, all of the drug
in this preparation is active
Bandolier website
OTC DRUG PREPARATIONS NOT
TO BE USED
y No ibuprofen with low dose
acetylsalicylic acid
y No over-the-counter analgesic
preparations containing codeine
y No concurrent use of different NSAIDs
y If you are taking low-dose
acetylsalicylic
t l li li acid
id ffor cardiovascular
di
l
prophylaxis, the only safe analgesic is
acetaminophen
RECOMMENDED COMPUTER
WEBSITE
y ***Bandolier
http://www.medicine.ox.ac.uk/bandolier/booth/painpag/index2.html
y Health Canada
y Not user friendly
y FDA
y Not user friendly
COMORBIDITIES THAT COMPLICATE
PAIN MANAGEMENT
y High blood pressure
y Blood coagulation modifiers
y Heart failure
y Kidney
Kid
di
disease
y Please see your health care worker for
acceptable pain management strategies.
Acetaminophen is likely to be the first drug
chosen
SUMMARY DRUG FACTS
y Ibuprofen is a mixture of two chemicals, only
y
y
y
y
one of which reduces pain. Some people can
convert the inactive form to the active form
Acetaminophen will not work well for pain
caused by inflammation
Caffeine will increase the efficacy of OTC
drugs sold to treat pain
Different drugs have different durations of
action
ti
For persistent pain, drug doses should be
taken at scheduled times and not only
y when
pain is severe.
Caffeine as a Co-analgesic
• Caffeine will increase the analgesic effect of all
nonopioid analgesic drugs
• The required dose for a co
co-analgesic
analgesic effect is 60
60-120
120
mg
• Patients who ingest foods and beverages that contain
caffeine may already be benefiting from the coanalgesic
g
effect
• Caffeine withdrawal is a major contributor to sudden
onset of headache
COMBINATION DRUG
PRODUCTS
y These are usually marketed as brand
names
y The same brand in Canada may
ma not
have the same ingredients as that
marketed in the USA – e.g.
g Excedrin®
y READ THE LABEL FOR THE LIST OF INGREDIENTS
y The only rational combinations are any
of the dr
drugs
gs mentioned toda
today with
ith
caffeine or acetaminophen with any
one of the other NSAIDs +/- caffeine