Narcotic analgesic for dental students

1. NARCOTIC ANALGESICS
Dental Clinical Pharmacology
By
Taha Hussein Kadi , MSc
Lecturer of Pharmacology & Toxicology
UST

2. Narcotics analgesics
• Analgesics are drugs that relieve pain without
significantly altering consciousness. They
relieve pain without affecting its cause.
• Narcotics analgesics are often necessary to
treat acute dental pain, especially in patients
who can not tolerate NSAIDs or whose pain
truly does not respond to NSAID therapy.

3. Opioid-receptors
• There are three types of
opioid receptors: mu
(μ), delta (δ), and kappa
(K).
• Opioid-receptor agonists
produce analgesia by
acting primarily at μ-
receptors found in the
brain, brainstem, spinal
cord, and primary
afferent sensory
neurons.

4. Mechanism of Action
• Presynaptic μ-receptor activation
inhibits calcium influx into sensory
neurons, which decreases
neurotransmitter release.
• Postsynaptic μ-receptor activation
increases K+ efflux , which
decreases postsynaptic response to
excitatory neurotransmission.

6. Classification of opioids
1. Opioid agonists
A. Natural opium alkaloids:
Morphine, codeine.
B. Semisynthetic opiates:
hydromorphone, oxymorphone.
C. Synthetic opioids: Pethidine,
tramadol, methadone, fentanyl,
alfentanil, remifentanil.
2.Opioid agonist–antagonists:
Pentazocine.
3. Partial μ-receptor agonist:
Buprenorphine.
4. μ-receptor antagonist:
Naltrexone

7. PHARMACOLOGIC EFFECTS
• Analgesia – MODERATE TO SEVERE PAIN
• Sedation and Euphoria
• Cough Suppression
• Gastrointestinal Effects – Constipation

10. ADVERSE REACTIONS
• Respiratory Depression
– Not a problem with usual doses in normal patients.
• Nausea and vomiting
• Constipation
• Miosis
• Urinary Retention
• Central Nervous System Effects
– opioids may produce CNS stimulation, exhibited as anxiety,
restlessness, or nervousness.
• Cardiovascular Effects
– Bradycardia and even syncope may result.
• Histamine Release - Allergy

11. ADVERSE REACTIONS
• Addiction
– The two major signs of opioid addiction are
cravings “an intense and overwhelming desire for
the drug”
– A loss of control of the ability to stop using the
drug or to control the amount of drug.
– Tolerance is normally not a problem for those who
take opioid analgesics for no more than 1-3 days,
as is the case in managing dental-related pain.
NSAIDs should be used to control dental pain in
the addict.

12. Identification of an Addict
• Requests a certain drug and says it is better
• Claims many allergies and says lots of pain
medications do not work.
• Cancels dental appointments because he or she
claims to be going out of town on business
• Experiences pain for days after scaling and root
planning
• Moves from dental office to dental office
• Claims a “low pain threshold”
• Needs refills several days after a dental procedure
without complications

13. • Overdose
– The major symptom of opioid overdose is
respiratory depression.
– Opioid overdose is treated with an antagonist,
naloxone.
• Withdrawal
– After abrupt discontinuation of an opioid, a
withdrawal syndrome occurs. The symptoms
include yawning, lacrimation, perspiration,
rhinorrhea, irritability, nausea, vomiting,
tachycardia, tremors, and chills.