Transcript ppchapter20pharmacology

CHAPTER
20
Nonopioid Analgesics,
Nonsteroidal
Antiinflammatories,
and Antigout Drugs
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20-2
Inflammation
• The inflammatory process is a normal
response to injury.
• Inflammation is considered the first
step in the process of healing.
• Inflammation can become
exaggerated, which leads to further
tissue damage.
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20-3
Inflammation
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20-4
Antiinflammatory Drug Action
• Steroidal antiinflammatory drugs
decrease inflammation by inhibiting
cyclooxygenase enzymes. (look at
article on COX-1 and COX-2)
• Nonsteroidal antiinflammatory drugs
decrease inflammation by inhibiting
prostaglandin synthesis.
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20-5
Nonopioids
• There are three groups within this
class distinguished by their
pharmacologic action:
– Salicylates
– Traditional NSAIDs
– COX-2 selective inhibitors
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20-6
Salicylates
• Aspirin and salicylic acid are the main
salicylates:
– Oldest and most frequently used
nonopioid analgesics
– Used as analgesics, antipyretics, and
antiinflammatories
– Discovered from Native Americans’ use
of willow tree bark
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20-7
Salicylates
• Salicylates produce analgesia and
antipyresis by affecting the hypothalamic
centers in the brain.
• Aspirin is a potent inhibitor of
prostaglandin synthesis, which decreases
inflammation.
• Salicylates block COX-1:
– Protective environment in stomach is altered
– Gastric ulcers can result
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20-8
Salicylates
• Aspirin:
– Helps reduce risk of reinfarction
– Prevents heart disease
• Salicylate intoxication:
– Nausea, vomiting, salicylism
• Aspirin should not be given to children with
chickenpox or flu symptoms:
– Reye’s syndrome
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20-9
Salicylates
• Aspirin:
– Used for mild to moderate pain, osteoarthritis,
and rheumatoid arthritis
– Reduces inflammation
• Aspirin safe for use in adults and children.
– Available in a variety of formulations:
• Capsules
• Tablets
• Solutions
• Gums
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20-10
Salicylates
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20-11
Acetaminophen
• Acetaminophen is effective in treating
headaches, fever, and minor
musculoskeletal pain.
– Inhibits prostaglandin synthetase
– Considered an aspirin substitute
– Does not have antiinflammatory
properties
– Not useful in the treatment of arthritis
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20-12
Acetaminophen
• Acetaminophen is available in a
variety of formulations:
– Suppository
– Solution
– Elixir
– Suspension
– Syrup
• It is available without a prescription
• Toxicity may develop from chronic use.
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20-13
Acetaminophen
• Treatment for overdose includes:
– Gastric aspiration and lavage
– Maintenance of fluid balance
– Activated charcoal
– N-acetylcysteine
• Because acetaminophen is available in
several OTC combination treatments,
toxicity is a concern.
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20-14
NSAIDs
• All NSAIDs interact with cyclooxygenases.
• Available primarily for oral administration.
• Older NSAIDs are nonselective. Newer
NSAIDs are selective COX-2 inhibitors:
– Reduce inflammation
– Pain relief not superior to older NSAIDs
– Lower incidence of ulcers and gastric
bleeding
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20-15
NSAIDs
• All antiinflammatory drugs may produce:
– Nausea, GI distress, and ulceration
– Vertigo, vomiting, mental confusion, and
headaches
• Overdose of NSAIDs is similar to salicylate
overdose.
– No specific antidote for NSAID poisoning
• NSAID use is discouraged in elderly
patients.
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20-16
NSAIDs
• Every OTC product with an NSAID should
include a warning for severe stomach bleeding
in people who:
–
–
–
–
Are aged 60 years or older
Have had stomach ulcers or bleeding problems
Take a blood thinning or steroid drug
Take other drugs containing prescription or
nonprescription NSAIDs
– Have three or more alcoholic drinks a day while
using the product
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20-17
Gout
• Gout is an inflammatory disease caused
by uric acid crystal formations in the joints
and soft tissue.
• Some foods with high purine content
precipitate gouty attacks.
• Inflammation of the joint is caused by
phagocytes trying to remove the uric acid
deposits.
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20-18
Drugs Useful in Treating Gout
• Drugs that are useful in the treatment of
gout either relieve the acute inflammatory
response or reduce uric acid levels.
• Colchicine alters the phagocytes’ ability to
attack the uric acid crystals.
• Colchicine causes nausea, vomiting,
diarrhea, and hematuria.
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20-19
Drugs Useful in Treating Gout
• Two major classes of drugs used in
long-term prophylaxis of gout:
– Hypouricemic agents
• Allopurinol
• Febuxostat
– Uricosuric agents
• Probenecid
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20-20
Drugs Useful in Treating Gout
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20-21
Drug Interactions
• Antiinflammatory drugs and nonopioid
analgesics undergo a variety of drug
interactions due to displacement on the
protein binding site.
• Aspirin may cancel the uricosuric effect of
probenecid.
• Rifampin and acetaminophen given
concurrently increase the risk of liver
toxicity.
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20-22
Preferred Therapy
• Aspirin:
– Fever, headaches, inflammation including
arthritis, prophylaxis of heart attack or stroke
• Ibuprofen:
– Aches, pains, inflammation
• Acetaminophen:
– Fever and headache, aspirin substitute
• Colchicine, allopurinol, and probenecid:
– Gout
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