Present the Pharmacology of Opioids, Including Chemical Changes and Mechanism of Action

Chance Peterson

11/1/2013

SOS-304 W.A. 5

Question 1

1.1 Present the pharmacology of opioids, including chemical changes and mechanism of action.

Opioids, such as morphine, codeine and heroin can be derived from raw opium and generally consist of carbon, oxygen and nitrogen. Acetyl groups facilitate penetration of the blood-brain barrier by opioids. The effects of heroin are more profound than those of morphine due to the additional acetyl groups on the heroin molecule. Besides having dependence-producing effects, opioids can also have analgesic and pain-killing effects. This occurs because they bind to pain receptors in the nervous system such as the mu and kappa receptor. The Opioids binding effects complex proteins embedded within the cell membrane of neurons. These receptors are found in areas relating to pain such as the thalamus, midbrain region, spinal cord and primary sensory neurons. (Hart, Carl and Charles Ksir, 2011)

1.2. Discuss why, if there are no chronic toxicities directly related to the use of opioids, opioid dependence would be a problem for users in the long term.

Opioid dependence will be a problem for users in the long term because it affects the brains biochemistry. The human brain is wired a specific way;this helps it to fulfill the functions that it needs to fulfill. The continued use of the opioid actually changes such wiring, over time. "Opioid dependence causes long-term changes in both the structure (the architecture of the brain) and the way the brain functions (the biochemistry of the brain)". (Stuckert, 2013)What this means is that long-term use can cause brain injury, of some sorts. At the very least a person will not function the same way they did, before becoming addicted. The opioid causes excessive stimulation of certain region in the brain; the longer the addict uses the drug, the worse the problem becomes. "Excessive stimulation of the reward pathway by an opioid ‘tricks' the brain into believing that an opioid is as necessary for survival as food and water". (Stuckert, 2013) A person who continually uses opioid will have a significant decrease in their intellectual capabilities. "To complicate matters further, the repeated use of an opioid has a profound impact on the intellectual portion of the human brain that is involved in judgment and decision-making". (Stuckert, 2013)

1.3. Discuss the changes in the populations of opioid users. Include in this discussion the debate around the availability of Naloxone.

There has been a reduction in the amount of opioid users today, due to strong anti-drug campaigns and a general cultural shift. There