Analgesics

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Chapter 26
Analgesics
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Types of Pain (acute, chronic)
Neuropathic
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Therapeutic Management of Pain
Acupuncture Electro- acupuncture
Nerve Blocks
Drugs
Irritants Heating Cooling Lotions Radiations
Non-Narcotics NSAIDs
Narcotics Opiates
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Opium ??

• Poppy Plant (Papaver somniferum??)
• Cultivated in
• Middle East (Afghanistan and Pakistan)
• Thailand
• South America and Mexico
• Incision of the poppy seed pod reveals a
• substance that turns into a brown gum that
• is crude opium.

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Fresh capsule of opium poppy
Cut capsule showing latex exuding from cut
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Morphine ??

• Actions
• CNS
• analgesia ????
• chronic continuous dull pain superior to acute
• discontinuous sharp pain
• relief of pain without the loss of consciousness
• accompanied with sedation and euphoria ??
• easy to fall asleep

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• respiration depression ????
• reducing the sensitivity of respiratory center to
  CO2
• the most common cause of death in acute overdose
• depression of cough reflex ??
• Stimulate some certain parts of cerebra
• miosis ?? pin-point pupils
• nausea and vomiting

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Peripheral effects

• Gastrointestinal tract
• decreasing motility of smooth muscle and
  increasing tone
• inhibiting gastric secretion
• inhibiting center and leading to dull in
  awareness
• of defecation ????
• constipation ??
• Biliary tract
• sphincter of oddi constrict biliary
  colic ???
• Uterus prolong labor

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• Renal urinary retention???
• sphincter of urinary bladder tension ?
• cardiovascular system
• postural hypotension??????
• vasodilatation ????
• the release of histamine
• cerebral vessels dilatation and CSF pressure
  increase
• respiratory depression and CO2 retention
• Immune system
• Both cell immunity and humoral immunity are
  inhibited

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Opioid Receptors

• µ analgesia, respiratory depression ,
• euphoria , dependence ,immunity
  inhibiton
• ? analgesia , dysphoria ????, mania,
• miosis ????
• d analgesia
• s

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morphine decreases the release of substance P
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• Therapeutic uses of morphine
• analgesia ?? various cause of pains
• especially when other analgesics are ineffective
• biliary colic ???, renal colic??? M (-)
• cardiac asthma ?????
• sedation?? and euphoria??, removing tension
• reducing the sensitivity of respiratory center to
  CO2
• dilating blood vessels, mitigating heart burden
• cough codeine (???)
• diarrhea

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• Adverse effects
• nausea and vomitting, constipation, pressure
  increase in the biliary tract
• tolerance and physical dependence
• withdrawal syndrome ?????
• acute poisoning
• respiratory depression , pin-point pupils
• antagonizer- naloxone ???
• Contraindication of morphine
• relieving expulsive pain, breast feeding
  women, newborn, bronchial asthma, craniocerebral
  trauma ?????

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SYMPTOMS OF WITHDRAWAL
Picture from www.schoolscience.co.uk/.../4/
biology/medicines/drugs4.html
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• Synthesized analgesics
• Pethidine ??? (dolantin, ???)
• Actions
• mainly activate m receptor
• Therapeutic uses substitute of morphine
• analgesia ??
• the same analgesic effect as morphine
• cardiac asthma ?????
• pre-anesthesia medication and artificial
  hibernation
• physical dependence!

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• fentanyl ???
• mainly activate m receptor
• 80 times the analgesic potency of morphine
• used as preoperative medication
• rapid onset and short duration of action
• (15 to 30 minutes)
• combined with droperidol ?????
• neurolepticanalgesia ??????

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• pentazocine ????
• an agonist on ? and a partial agonist at µ
  receptors
• producing less euphoria?? than morphine
• high doses increase blood pressure and can cause
  hallucinations??, tachycardia and dizziness
• mainly used in chronic pains
• belonging to nonrestrictive analgesics
• rotundine ???
• mainly used in chronic dull pain???? and
  visceralgia???
• no addiction???

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• Opioid receptor antagonist
• naloxone???, naltrexone???
• competitive µ, d, ? receptors antagonists
• rapidly reversing respiratory depression and
  blood pressure fall of opioid overdose
• used in emergency treatment of opioid overdose