History/Background
Opioids have been used for thousands of years for pain treatment. Papyrus records from the ancient Egyptians report the use of opium, within the opioid family for pain relief. The opium poppy was grown as early as 3400 BC in Mesopotamia. “Opium” refers to a combination of alkaloids from poppy seeds while opiates are natural alkaloids in the morphine or codeine family. However, the term “opioid” is used as a broad definition of compounds that function as opioid receptors. The term “narcotic,” from the Greek word for “stupor,” originally described sleep medications and after used to describe opioids, which is currently a legal term (“opioids”) for drugs that are abused (Trescot, Datta, Lee & Hansen, 2008).

Pharmacology
According to Pathan & William, “There are three classical opioid receptors (DOP, KOP and MOP), while the novel NOPO receptor is considered to be a non-opioid” (2012). “Opioids may also be classified according to their mode of synthesis into alkaloids, semi-synthetic and synthetic compounds” (Pathan & William, 2012). The pharmacological effects of the opioid analgesics are derived from their complex interactions with three opioid receptor types (mu, delta, and kappa; morphine is an agonist at the mu opioid receptor). Inturrisi writes that the receptors can be found in the “periphery, at presynaptic and postsynaptic sites in the spinal cord dorsal horn, and in the brain stem, thalamus, and cortex, in what constitutes the ascending pain transmission system” (2002).

Delivery system and Use
Opioids such as morphine can be taken orally or through an IV. Generally, opioids can be administered through oral, rectal, transdermal, intravenous and intra muscular delivery. Opioids are pain reducing medications that effect the pain signals reaching the brain. They also effect the part of the brain that controls emotion which reduces or eliminates painful stimulus. There are several medications that fall within the opioids class, including hydrocodone (Vicodin), oxycodone (OxyContin and Percocet), morphine (Kadian and Avinza) and codeine. Hydrocodone products are the most commonly prescribed for pain and morphine if commonly used before and after surgical procedures and for end-of-life care, particularly in cancer patients to eliminate pain. Codeine is often prescribed to reduce mild pain (NIH, 2014.).

According to the American Society of Interventional Pain Physicians, 10 million Americans suffer from chronic, disabling or persistent pain, consuming eighty percent of the global opioid supply and ninety-nine percent of the global Hydrocodone supply. In addition, Americans consume two-thirds of the world’s illegal drug supply (2014.). How opioids work is that they attach to opioid receptors (proteins) found in the brain, gastrointestinal tract and other bodily organs. By attaching to receptors, the opioids reduce the perception of pain. They can also cause euphoria and people who abuse opioids can seek to intensify this experience with other drugs (NIH, 2014) an example is OxyContin, an oral pain medication that slowly releases opioids. It can be snorted or injected.

If taken as a large, single does, opioids can lead to severe respiratory distress or death. Regular or long term use can lead to physical dependence and withdrawal symptoms (NIH, n.d.). There is also a confirmed relationship between opioid overdoses and slowed breathing and long-term effects on brain function. Studies are showing the brain’s white matter can deteriorate from over use of heroin (NIH, 2014).

There is a risk of accidental overdose with opioids use. Patients should avoid combining them with other medications that can cause sleepiness, including alcohol, some anti-anxiety medications, muscle relaxants and sleep aids.