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Side Effects of


Description: Opioids are medications used to treat moderate or severe pain. They relieve discomfort by binding to opioid receptors in the brain and spinal cord. They are chemically similar to narcotic drugs that are not prescribed and are, in fact, illegal to use or possess, including opium and heroin. Regardless of their legality, all types of opiates work in the same way and can cause identical adverse reactions.

The Most Serious Opioid Side Effects

Unfortunately, excessive amounts of opioids can cause an overdose syndrome that can be fatal. If opioid levels are too high, the affected person may become unaware of his or her surroundings, may lose consciousness, and have progressively slower breathing until breathing stops altogether. Overdose is one of the most feared serious opioids side effects, particularly among those who have become accustomed to high doses of prescribed opioids. (The New England Journal of Medicine “A Proactive Response to Prescription Opioid Abuse,” Apr 2016).

Warning on Physical and Psychological Addiction to Opioids

In opioid addiction, the body becomes physically dependent on the drug and requires more and more of the medication to feel “normal.” This also leads to psychological dependence in which the person suffering for opioid addiction feels as if they cannot make it through life without opioids. The risk of opioid addiction is relatively low in people who have cancer pain or who use opioids over short period. Conversely, the risk of opioid addiction is quite high in people who use illegal opioids or prescribed opioids for chronic pain conditions such as chronic low back pain. (The New England Journal of Medicine “A Proactive Response to Prescription Opioid Abuse,” Apr 2016).

Common Opioids Side Effects: The Gastrointestinal Tract

Opioids affect the gastrointestinal system profoundly. This is especially true of opioids taken orally, such as oxycodone and hydrocodone. Stimulation of opioid receptors in the gut causes the normal movement of the gastrointestinal tract to slow down. This results in nausea, vomiting, and constipation. In fact, chronic constipation can be so severe that people, particularly those compromised individuals being treated for cancer, develop bowel obstruction. Gastrointestinal effects are by far the most common opioids side effects. (Contemporary Oncology “The impact of opioid analgesics on the gastrointestinal tract function and the current management possibilities,” Feb 2012).

Understand Your Risks with the Rxight® Genetic Test

Pharmacogenetics allows patients to learn their own personal genotype as it applies to the metabolism of pharmacological agents. Rxight® DNA testing provides patients with their genotype in one convenient test panel, along with a detailed analysis of their metabolism of medications, which will be reviewed with you by a pharmacist trained in pharmacogenetic testing. This genotype includes the genes that code for metabolic enzymes which process opioids and hundreds of prescription and over-the-counter medications across dozens of pharmacological classes.

How Does Pharmacogenetic Testing Work?

Many people have normal liver enzyme drug metabolism responsible for processing opioids. However, some people may have abnormalities in one or more of these liver enzymes, which could lead to dangerously high or ineffective levels of opioids. In the latter case, higher levels of opioids are required to achieve pain relief. In the former case, serious and potentially life-threatening side effects can result.

Contributors to this Article:
Michael Sapko, MD, PhD; Deborah Kallick, PhD, Medicinal Chemistry

Opioids Tested Include:

Read more about Rxight® Pharmacogenetics