Common Opioids

 

The locations of highly concentrated regions of opiate receptors in the body correspond well with the known effects of the drugs.  Table 1 highlights the body regions with a high density of opiate receptors and the effects of activating these receptors.  Opioids exert their most profound effects in specific regions of the body.  Table 2 outlines the major effects of commonly used opioids.
Table 11
Location of Receptors 

1. Substantia gelatinosa and 
    medial thalamus in brain 

2. Brain Stem 
 

3. Limbic system in 
    brain 

4.  Large Intestines 

  Effects of Receptor Activation 

Pain relief for dull, prolonged pain 
(analgesia) 

Cough suppression, respiratory 
depression, pupil constriction 

Euphoria 
 

Constipation
 
 
 
 
 
 
 

 
Heroin, bagged for  
weighing and in its 
powder form.  Images  
on this page from  
Greater Manchester  
Police. Used with  
permission.
Table 2 2
  
Opioid 

1. Morphine 
 
 

2. Codeine 
 

3. Heroin 
 
 

4. Hydromorphone 
 

5. Oxydone 
 

6. Fentanyl 
 
 

7. Methadone 
 
 

8. Naloxone 
  (not an opioid)
 

 Description 

Medically used for pain relief. Respiratory system 
depressant. Naturally exists in opium.  Activates mu 
opiate receptors. 

Medically used for pain relief and cough suppression. 
Naturally exists in opium. 

Semisynthetic drug illegally used (in the USA) for its 
euphoric effect.  No accepted medical uses. 
Depresses respiratory system.

Semisynthetic. Used to suppress cough and reduce 
diarrhea. 

Semisynthetic. Medically used for pain relief, cough 
suppression, and to treat diarrhea. 

Synthetic. Very potent analgesic properties. Full 
agonist at mu receptors. Used as an anesthetic during
surgery. 

Synthetic. Weak, long lasting drug.  Used to reduce 
withdrawal symptoms of heroin addicts who are trying
to quit.

Semisynthetic. Strong antagonist at opiate receptors. 
Used to reduce the effects of opioids and treat opioid 
overdoses.
 
 

 
 
 
 

 
Methadon in its 
pill and liquid form.
1 Information for this table was compiled using the following sources: Leonard, 1992; Rang et al., 1995; Iversen, 1996; and
  Snyder, 1996.
2 Information for this table was compiled using the following sources: Leonard, 1992; Rang et al., 1995; Snyder, 1996; and
  Greater Manchester Police.
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   This site was created during the fall semester of 1999 by Wes Self, a student at 
  Davidson College, as part of an assignment in Biology 312 (Animal Physiology). 

  Questions, comments and suggestions are appreciated at weself@davidson.edu