Chapter 6
Nonopiod (Nonnarcotic) Analgesics
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Nonopioid Analgesics
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Pain is an unpleasant sensory or
emotional experience arising from actual
or potential tissue damage.
A person’s response to pain is based on
their perception of pain.
Both perception and reaction to pain are
often psychologically based.
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Salicylates
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Acetylsalicylic acid (aspirin) is the most
common salicylate used today.
Aspirin is the most useful salicylate for
treating pain.
Aspirin works by inhibiting prostaglandin
synthesis.
It primarily inhibits the enzyme
cyclooxygenase (COX).
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Salicylates
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Aspirin is rapidly and almost completely absorbed
from the stomach and small intestine.
It reaches its peak effects in 30 minutes when
taken on an empty stomach.
Buffered tablets reach their peak effect in 20
minutes.
Most aspirin is coated because it is irritating to the
stomach.
Aspirin can be administered rectally.
Aspirin demonstrates zero-order kinetics.
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Salicylates
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Pharmacologic Effects
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Analgesic
• It is used to treat mild to moderate pain, including
dental pain.
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Antipyretic
• Aspirin reduces fever because of its ability to inhibit
prostaglandin synthesis in the hypothalamus.
• Aspirin reduces fever by inducing peripheral
vasodilation and sweating.
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Salicylates
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Pharmacologic Effects
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Antiinflammatory
• This effect is also from aspirin’s ability to block
prostaglandin synthesis.
• Aspirin reduces redness and swelling at the inflamed
area.
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Antiplatelet
• Aspirin irreversibly binds to platelets.
• Aspirin inhibits both prostacyclin and thromboxane
A2 depending on the dose used. This helps prevent
blood from clotting.
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Salicylates
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Adverse Reactions
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Aspirin’s adverse reactions are many. These
reactions have limited aspirin’s everyday use.
The many adverse reactions of aspirin include:
• Gastrointestinal – They are a direct result of direct
gastric irritation and blockage of prostaglandins.
• Bleeding – Bleeding time is prolonged because of
aspirin’s effects on platelets and prostaglandins.
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Salicylates
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Adverse Reactions
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Reye syndrome
 Hepatotoxicity
 Renal toxicity
 Hypersensitivity
• Patients with asthma are at a higher risk for
hypersensitivity or allergic reactions.
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Salicylates
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Salicylates
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Uses
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Mild to moderate pain
 Fever
 Inflammation
 Prevention of stroke or heart attack
 Antiplatelet effects
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Nonsteroidal Antiinflammatory
Drugs (NSAIDs)
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NSAIDs are among the most useful drugs available to
treat dental pain.
Several of these drugs are available without a
prescription.
As with aspirin, NSAIDs work by inhibiting the enzyme
cyclooxygenase.
Most NSAIDs demonstrate peak effects within 1-2
hours.
Food reduces the rate but not the extent of NSAID
absorption.
Pharmacologic effects are similar to aspirin and
include analgesic, antipyretic, and antiinflammatory
actions.
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NSAIDs
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Adverse Reactions
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As with aspirin, adverse reactions include
gastrointestinal effects, renal effects, and
hypersensitivity reactions.
 NSAIDs can cause central nervous system
effects including sedation, dizziness,
confusion, depression, and headache.
 NSAIDs reversibly inhibit platelet aggregation.
This effect only remains as long as the drug is
in the body.
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NSAIDs
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NSAIDs
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NSAIDs
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Therapeutic Uses
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Medical
• Osteoarthritis, rheumatoid arthritis, general pain and
inflammation, fever, dysmenorrhea
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Dental
• General dental pain and inflammation
• Often better than opioid analgesics
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NSAIDs
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Cyclooxygenase II (COX) Specific Agents
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COX II is only synthesized when inflammation is
present.
Blocking COX II receptors only should decrease
the risk for adverse effects. Blocking COX I
appears to be responsible for adverse effects.
These drugs were thought to be less irritating to the
stomach.
However, these drugs can cause significant
cardiovascular and gastrointestinal toxicity.
They offer no advantage over nonselective
NSAIDs.
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Acetaminophen
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Acetaminophen is not related to salicylates or
NSAIDs.
It is rapidly and completely absorbed from the
gastrointestinal tract.
It achieves peak levels in 1-3 hours.
Acetaminophen is metabolized by the liver.
If large doses are ingested, an intermediate
metabolite, N-acetyl-p-benzoquinonamine is
formed. This metabolite is toxic.
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Acetaminophen
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Acetaminophen has both analgesic and
antipyretic effects.
Therapeutic doses have no effect on the
cardiovascular and respiratory system.
It does not have any real gastrointestinal
effects.
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Acetaminophen
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Adverse Effects
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Hepatotoxicity
• Can occur after the ingestion of a single toxic dose
(20-25 gm) or after long term use of therapeutic
doses.
• Children are at high risk for hepatotoxicity because
they are often given doses that are not age- and
weight-appropriate.
• Signs and symptoms include nausea, vomiting,
abdominal pain, anorexia.
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Nephrotoxicity
• It has been associated with long-term use.
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Acetaminophen
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Chronic large doses of alcohol can
increase the risk for hepatotoxicity.
Acetaminophen is used for its analgesic
and antipyretic effects.
It is useful in patients with aspirin or
NSAID hypersensitivity.
It is useful for children because it is not
known to cause Reye syndrome.
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