OPIOID/ Analgesic সম্পর্কে জানি

পোস্ট টি ভালো লাগলে আপনার বন্ধুদের সাথে শেয়ার করুন
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OPIOID/ Analgesic সম্পর্কে জানি

Strong: Morphine, Methadone, Meperidine, Moderate, Codeine, Oxycodone

Weak: propoxyphene, Mixed (Agonists-antagonists), Buprenorphine, Nalbuphine

Antagonists: Naloxone, Naltrexone

Clinical Uses:

Analgesia- Fentanyl, morphine

Cough Suppression- Codeine, Dextromethorphan

Antidiarrheal- Diphenoxylate, Loperamide

Acute pulmonary edema- Morphine

Anesthesia- Fentanyl

Opioid Dependence- Methadone

Pharmacokinetis:

  • Well absorbed orally
  • Morphine, hydromorphone, oxymorpine, undergo first-pass metabolism
  • Cross placental barrier and effect fetus, cause respiratory depression, physical dependence in neonates.

Metabolism: By hepatic enzymes, inactivated by glucuronide conjugates before elimination from kidneys-.

*morphine-6-glucuronide (analgesic)

*Morphien-3-glucuronide (neuroexciatory)

Mechanism of Action: Opioids produce analgesia by binding to specific G protein coupled receptors in brain & spinal cord.

Mechanism Of Action:

  • Receptors: µ, Ȣ, K receptors

All 3 subtypes are involved in antinociception and analgesic mechanisms at both spinal and supraspinal levels.

  • µ receptors- respiratory depressant+ GI
  • Ȣ receptors- development of tolerance
  • Kreceptors- involved in sedation+ GI

Opioid peptides:

  • β- endorphin, (µ, receptors)
  • Enkephalins (Ȣ receptors)
  • Dynorphins (K receptors)
  • Modulate transmission in brain, spinal cord, adrenal medulla and neural plexus of gut.
  • All 3 receptors are in high concentration in dorsal horn of spinal cord.
  • Direct application of opioid agonists at spinal cord produce regional analgesia.
  • Respiratory depression, nausea, vomiting, sedation from supraspinal action.

Ionic Mechanisms:

  • Presynaptic level close voltage gated Ca+ channels, and reduce transmission.
  • Post synaptic level open K+ channels (inhibit post synaptic neurons)

Effects:

  • Analgesia

Most powerful analgesics, Morphine, methadone, meperidine, fentanyl, heroin

  • Sedation and euphoria
  • Respiratory depression

Action at medulla lead to respiratory depression

  • Antitussive Effects

Suppression of the cough reflex

  • Nausea & vomiting

Activation of chemoreceptor trigger zone

Side Effect:

  • GI effects

Constipation with decreased intestinal peristalsis

  • Smooth muscles

cause contraction of biliary track SM, ureter and bladder tone, ted, Uterine tone (prolong labor)

  • Meiosis
  • Tolerance
  • Dependence

আরও পড়ুনঃ জেনে নিন কোন ড্রাগের সাথে কোন ড্রাগ নেয়া ঠিক না।

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