Chemical substance that has morphine-like action in the body is an opioid. Its main use is for pain relief. The way that they work is to bind opioid receptors that are found in th central nervous system and in the gastrointestinal tract. The receptors in these organ systems mediate both the beneficial effects and the undesirable side effects. The four classes to narcotics are:
Endogenous peptides-naturally produced in the body
Opiates-these are produced by morphine
Semi-synthetic opioids-hydromorphone & oxycodone
Fully-synthetic opioids-fentanyl & methadone
Common adverse reactions in patients taking opioids for pain relief are nausea, vomiting, drowsiness, dry mouth, and constipation. Adverse reactions in patients that take opioids that infrequently happen and are usually dose-related are respiratory depression, confusion, hallucinations, delirium, hypothermia, bradycardia (low heartrate), tachycardia (fast heartrate), dizziness, headache, urinary retention, and muscle rigidity. Some experience hyperalgesia, which is when a patient using opioids for pain relief may have more pain as a result of their medication.
Both therapeutic and chronic use of opioids can compromise the function of the immune system. Other concerns about opioids are tolerance, dependence, addiction, and abuse. The issuses can cause doctors and patients concerns and they are the most common reason for which inadequate use of analgesia for patients with chronic pain. Putting these issues into the context of analgesia is important.
Tendency for the body to adapt to the presence of opioids it is a common reaction to all chemicals, even caffeine. Dependence is the tendency of the body to mainifest a characteristic and unpleasant withdrawal syndrome if regular doses of opioids are abruptly discontinued after tolerance has developed. Addiction is a psychological craving for certain effects of opioids, such as euphoria, that many people experience when the drugs are taken in large doses. In the context of addiction abuse is the misuse of opioids.