Ch. 2: Introduction to Opioids

This chapter briefly introduces the opioid substances. The contents specifically about opioids come from a longer document published by the National Institute on Drug Abuse (NIDA, 2016) called Misuse of Prescription Drugs.

In this chapter you will read about:

• opioid drugs and how they affect the brain/body;
• dependence, addiction, and tolerance;
• opioid misuse and chronic pan;
• the problem of tolerance and overdose;
• injection drug use as a health problem; and,
• key terms used in the field of substance use disorders and addiction.

You might ask, “Why are we reading about tolerance again at this point in the course?” There is a special situation related to opioids and tolerance that warrants attention. This segment written about heroin gets to the point:

During a period of abstinence (for example, in treatment or in custody), tolerance diminishes quickly so that an individual can easily overdose by taking their usual dose. Overdose occurs as a result of depression of the respiratory centre [sic] in the brain, which leads to respiratory and cardiac arrest and death unless immediate medical attention is received (Rassool, 2011, p. 73).

In other words, a person who stops taking heroin or other opioid drugs quickly loses the tolerance that may have built up over time. Resuming use at the previous amount of the drug becomes an overdose.

The symptoms of heroin overdose presented in a table by Rassool (2011, p. 73) are:

• shallow breathing or difficulty breathing
• weak pulse and/or low blood pressure
• delirium
• drowsiness
• muscle spasms
• disorientation
• bluish-color of lips and fingernails (from low oxygen levels)
• dry mouth
• pinpoint (small) pupils
• coma.

Rassool (2011) also addressed an additional important issue related to opioid misuse, particularly related to heroin: injection as a common mechanism of heroin administration. Injecting drugs is accompanied by a host of potential health problems, including infection at the injection sites, vein collapse at the injection sites, and contracting or transmitting infectious diseases through “dirty” needle sharing (HIV, hepatitis B and hepatitis C).