1. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Chapter 7 Opioid (Narcotic) Analgesics and Antagonists

2. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Opioid (nonnarcotic) analgesics are used to manage dental pain in patients who cannot tolerate NSAIDS or when NSAIDs are contraindicated.  Opioid analgesics are divided into three groups—opioid agonists, mixed opioids, and antagonists. 2

3. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Mechanism of Action  Opioid analgesics bind to several different opioid receptors in the CNS and spinal cord to produce therapeutic and adverse effects.  These drugs alter the patient’s perception or reaction to pain.  Opioids can be complete agonists, partial agonists, agonist-antagonists, or antagonists at the receptor site. 3

4. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Mechanism of Action  Stimulation of μ receptors produces analgesia, sedation, miosis, pruritus, respiratory depression, euphoria, physical dependence, constipation.  Stimulation of κ receptors produces analgesia, sedation, and myosis.  Stimulation of δ is thought to produce analgesia.  Stimulation of σ receptors produces autonomic stimulation, dysphoria, hallucinations, nightmares, and anxiety.  Stimulation of ε receptors produces analgesia. 4

5. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Pharmacokinetics  Most opioid analgesics are well absorbed from the gastrointestinal tract.  Absorption also occurs from the lungs, nasal and oral mucosa, and the skin.  Opioids are bound to plasma protein to varying degrees and are also distributed to the placenta.  These drugs are metabolized in the liver and undergo variable first-pass metabolism.  These drugs are excreted by the kidneys. 5

6. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Pharmacologic Effects  These drugs produce varying degrees of analgesia depending on the strength of the individual drug.  Morphine is the opioid agonist by which all others are measured.  Opioid analgesics produce euphoria and sedation at usual therapeutic doses.  Opioid analgesics depress the cough center in the medulla and produce an antitussive effect.  Opioid analgesics increase smooth muscle tone and decrease propulsive contractions and motility. This effect makes them useful for treating diarrhea. 6

7. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Adverse Reactions  Adverse reactions are an extension of the opioids’ pharmacologic effects.  Adverse reactions are proportional to opioid analgesic strength.  Adverse reactions are many and include respiratory depression, nausea and emesis, constipation, myosis, urinary retention, CNS depressant effects, and histamine release. 7

8. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics 8

9. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Addiction  The degree of addiction is related to opioid analgesic strength.  Addiction is usually not a problem in dentistry because the duration of action is short and weaker opioids are used.  The rate of development of tolerance is related to the strength of the opioid and the frequency of use. 9

10. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Overdose and Withdrawal  The major symptoms of opioid analgesic overdose include respiratory depression, pinpoint pupils, and coma.  Withdrawal occurs with the abrupt discontinuation of opioid analgesics.  Symptoms include yawning, lacrimation, perspiration, rhinorrhea, gooseflesh, irritability, nausea, vomiting, tachycardia, tremors, chills.  Addiction, overdose, and withdrawal can be treated with opioid antagonists. 10

11. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Red Flags of Addiction  Asks for the opioid analgesic by name and says that this is the only drug that works for them  Patient claims allergies to NSAIDs or lower potency opioid analgesics  Calls with a request for an opioid analgesic just as the office is closing or after hours  Cancels dental appointment but still requests the opioid analgesic even though they will be “out of town on business”  Continually changing practitioners 11

12. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Red Flags of Addiction  Claims a “low pain threshold”  Experiences pain for days after scaling and root planing  Needs refills several days after an uncomplicated dental procedure 12

13. Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Opioid Analgesics  Allergic Reactions  The most common allergic reactions are skin rash and urticaria.  They are due to the histamine-releasing properties of opioid analgesics.  Drug Interactions  Opioid analgesics produce additive CNS depressant effects when given with other drugs that depress the CNS. 13