Synthetic opioids

SYNTHETIC OPIOIDS

Codeine

  • Substitution of hydroxyl moiety with methyl group on 3 position 
  • Analgesic potency is one tenth the potency of morphine
  • Absorbed readily from GI tract,the absorption is more regular and predictable than morphine 
  • Metabolized like morphine through glucuronic acid
  • Physical dependence is necessity of drug so you don't go through withdrawal
  • Tolerance and physical dependence is protracted from morphine since potency of codeine is low
  • Withdrawal from codeine is mild in relation to morphine
  • Antitussive

Heroin (diacetylmorphine)

  • Substitution with acetyl groups at 3 and 6 hydroxy positions 
  • Analgesic potency is 3 to 4 times more of morphine
  • Most lipophilic of all the OPIOIDs
  • Morphine is the least lipophilic of all the OPIOID
  • Crosses the blood brain barrier rapidly (morphine crosses slowly)
  • Hydrolyzed to mono acetyl morphine, then to morphine making more of the drug in the brain making it 3 to 4 times more potent withdrawal symptoms of heroin similar to morphine, but more intense (rebound effect, mydriasis, diarrhea, vasoconstriction, dysphoria etc.)

Hydromorphone

  • Substituted with  ketone at 6 hydroxyl position of morphine
  • Strong agonist
  • Highly potent
  • More sedative than morphine so less euphoric
  • Less constipation
  • Does not produce miosis
  • Tolerance and physical dependence is more intense than morphine because of its high potency
  • Respiratory depression

Fentanyl

  • Synthetic drug
  • More potent than morphine
  • Rapidly acting 
  • Short acting (30-45 min)
  • Onset of action is 5 minutes
  • Very highly potent
  • Highly abused - known as china white as street name

Meperidine

  • Addictive liability as morphine
  • CNS effective actions as morphine
  • Sedation, analgesia, respiratory depression
  • Highly potent as morphine 
Last modified: Wednesday, 16 May 2012, 5:04 AM