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Notes
      3. Old stuff
          3.1. Old pharm stuff (pre 2009)
              3.1.3. Pharmacology
                  3.1.3.5. Opioids
 3.1.3.5.5. Opioid antagonists 
 1. Naloxone
 2. Naltrexone
 3. Nalmefene
 4. Methylnaltrexone

Opioid antagonists

[SH4:p120-121]

Class

Pure MOP receptor antagonists with no agonist activity

  • Naloxone
  • Naltrexone
  • Nalmefene

High affinity for MOP receptors is characteristic

Structure

  • Changes in the structure of an opioid agonist can convert the drug into an antagonist
  • Most common change is substitution of an alkyl group for a methyl group on an opioid agonist
    * e.g. naloxone is the N-alkyl derivative of oxymorphone

 

Trivia

Old antagonists also had some agonist activities
* e.g. nalorphine, levorphanol
* Now been replaced

 

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Table of contents  | Bibliography  | Index
Revised at 2007/01/02 23:23