Analgesics (Part 1) PDF

Analgesics Dr. Nesreen El-Gayar  Outlines Analgesics. Opioids: ✓Morphine ✓Synthetic opioids.  Analgesics Drugs that relieve pain due to multiple causes  Analgesics Non Opioids Opioids NSAIDs Morphine Paracetamol...

Analgesics Dr. Nesreen El-Gayar  Outlines Analgesics. Opioids: ✓Morphine ✓Synthetic opioids.  Analgesics Drugs that relieve pain due to multiple causes  Analgesics Non Opioids Opioids NSAIDs Morphine Paracetamol Synthetic opioids Opioid Analgesics heroin needle Used in moderate to sever pain  Analgesic Ladder Strong Opioids NSAIDS + weak Opioids NSAIDS Opium Poppy  Opium Poppy Harvesting opium. Opium ‫االفيون‬ Morphine “Opium” is a Greek word meaning “juice,” or the exudate from the poppy “Opiate” is a drug extracted from the exudate of the poppy “Opioid” is a natural or synthetic drug that binds to opioid receptors producing agonist effects Opioid Analgesics Morphine - Like Drugs  GOD’S Medicine Analgesia Sedation Euphoria Antitussive Antidiarrheal  Morphine Morpheus God of Dreams Sedation Narcosis Sleep heroin needle Narcotic Analgesics  Narcotic A chemical agent that induces stupor, coma, or insensibility to pain Usually refers to Opioid Analgesics  Endogenous Opioid-peptides Endorphins Dynorphins Encephalin Analgesia - Euphoria Exogenous Endogenous Opioids Opioids (+) (+) Mu - Delta - Kappa Receptors  Uses Actions Adverse Effects & CI 1. Analgesic e.g. I. Main Effects Masks pain CI: acute Acute trauma. A. Analgesia undiagnosed Postoperative abdomen Cancer pain B. Sedation Sedation – C. Euphoria Narcosis 2. In Anesthesia Pre-anaesthesia Drug CVS surgery dependence  Uses Actions Adverse Effects & CI II. Inhibitory Effects A.  Cough center Delayed labor 3. Antitussive B.  Uterine tone Respiratory Replaced by  delayed labor depression Codeine & C. Respiratory center & asphyxia Dextromethorph → CO2 → Cerebral VD neonatorum an & ↑intracranial tension (less addictive) (ICT)  ICT CI: head injury  Uses Actions Adverse Effects & CI III. Stimulatory Meiosis 4. Antidiarrheal Nausea - vomiting Effects Loperamide Urine Retention A.  Oculomotor nucleus Diphenoxylate  meiosis (CI: enlarged prostate (less addictive, more B.  CTZ  vomiting Constipation widely used) C. Urinary & GIT ↓BP– itching –  Tone (wall & sphin.) bronchospasm (spasmogenic) but  peristalsis CI: Asthma D. Histamine release Tolerance develops to all effects except constipation and meiosis.  Classification of Opioid Analgesics 1. Strong 2. Moderate 3. Weak A. Pure Agonists Codeine Propoxyphene Morphine (Oral) (Oral) Fentanyl Analgesic. Analgesic Pethidine Antitussive. Heroin B. Partial agonists Buprenorphine  Pethidine [IM - Oral] Used in acute moderate & severe pain e.g, postoperative pain, or labor Pethidine differs from morphine in: 1. Less constipation 2. Less urinary retention (shorter acting). 2. Less respiratory depressant in neonates & does not delay labor  preferred during labor 3. Atropine-like action: dry mouth, blurred vision, ….....  Fentanyl More potent than morphine with rapid onset & shorter action. Uses 1.Analgesic in severe pain e.g. perioperative, labor & cancer pain. 2. In Anesthesia: as preanesthetic medication and anesthetic in CVS surgery (safer).  Buprenorphine (partial agonist) Advantages over Pure Agonists 1. Less addiction (less euphoria  less craving). 2. Less respiratory depression Uses (parentral, sublingual) 1. Analgesic in severe pain. 2. Treatment of opioid addicts  Acute Morphine Toxicity Coma Respiratory depression. Pin pointed pupil (diagnostic). Treatment Support respiration. Naloxone (IV): opioid antagonist  Drug Interactions of Opioids 1. Opioids + other CNS depressants (sedatives, alcohol, antidepressants & antipsychotics)  additive CNS depression. 2. Partial agonist + pure agonist  withdrawal syndrome &  analgesic effect.