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Drugs Used to Treat Pain: Opioids - Narcotics

Peer Reviewed

There are many different types of drugs used to treat back and neck pain. These drugs include narcotics and non-steroidal anti-inflammatory drugs (NSAIDs). Although the terminology is not precisely correct, pain-relieving opioids are often called narcotics, and they may be prescribed to treat acute pain (severe, short-lived pain), post-operative pain and certain types of chronic pain. Sometimes the treating physician will prescribe an NSAID with a narcotic to relieve pain associated with inflammation.

pills, drugs

Taking pain medication is a serious decision and the patient should be aware of the possible side effects from a single drug taken as well as the dangers of combining different medications. This is a decision that should be made with the treating physician who knows the patient’s medical history.

The purpose of this article is to help patients understand what an opioid narcotic is, how they work, the common side effects, and drug induced symptoms that may warrant medical attention.

Opioids: Powerful Narcotic Drugs
Opioids have been used for centuries to relieve pain. Those opioids that are derived from the seedpod of the poppy plant (papaver somniferum) are referred to as opiates. Morphine and codeine are commonly known opiates derived from opium. Other opioids include synthetics such as meperidine (Demerol) and chemicals naturally found in the body, such as endorphin.

How Drugs Treat Pain
Opioids work to relieve pain in two ways. First, they attach to opioid receptors, which are specific proteins on the surface of cells in the brain, spinal cord and gastrointestinal tract. These drugs interfere and stop the transmission of pain messages to the brain. Second, they work in the brain to alter the sensation of pain. These drugs do not take the pain away, but they do reduce and alter the patient’s perception of the pain.

Factors Affecting “Effect”
The effects of any drug depends on the amount taken at one time, the patient’s past experience with the drug, and whether the drug is injected, administered intravenously or taken orally. The patient’s psychological and emotional stability may also affect the effect of the drug. Of course, combining drugs with other opioids or alcohol can produce profound side effects. Some side effects can be harmful or lethal.

Tolerance
Chronic opioid use may result in a tolerance to the drug. This means that higher doses of the drug are needed to obtain the same initial pain relieving effects. Some patients develop a cross tolerance, which means prolonged use of one opioid may cause a tolerance to develop to all opioids.

Common Side Effects
All drugs cause side effects. Some are acceptable and others are bothersome or even dangerous. Common side effects include euphoria, drowsiness, nausea, vomiting, constipation, dilated pupils and respiratory depression. The patient should always report side effects to the treating physician.

Withdrawal
The body adapts to the presence of an opioid. Withdrawal symptoms appear when drug usage is reduced or abruptly stopped. Symptoms of withdrawal may begin as early as a few hours after usage is dramatically lowered, and the symptoms peak two to three days thereafter. Never alter the prescribed dosage or stop an opioid without the treating physician’s knowledge and advice.

Withdrawal symptoms include a craving for the drug, restlessness, moodiness, insomnia, yawning, abdominal cramps, diarrhea and goose bumps.

Conclusion
Pain is personal -- no two patients perceive pain in the same manner. This is one reason why patient/physician communication is important to manage pain effectively. There are hundreds of drugs and other treatments available to treat back and neck pain. Managing pain does not have to be a solitary effort when patients and physicians work together.

Updated on: 02/01/10
Steven Richeimer, MD
The comment made by Dr. Novak (below) is correct. Most opioids cause pupil constriction. The withdrawal of opioids will cause dilation.

By: F. Patrick Novak, MD - Anesthesiologist

Used properly, opioids have a significant role to play in the relief of pain. Acute post-op pain is the most universal use for opioids. However, there are uncommon circumstances when opioids are beneficial to treat severe chronic pain. I would like to correct Dr. Richeimer's statement about "dilated pupils."

Morphine and most mu and kappa agonists cause a dose-related constriction of the pupils by excitation of the parasympathetic nervous system, which innervates the eye muscles and thus the pupils.

A prominent exception to this rule is the semi-synthetic/synthetic opioids. Semi-synthetic: meperidine (Demerol) causes pupillary dilation. The modern, fully synthetic opioids (which have a physical structure based on the synthetic moiety of the meperidine molecule) can cause focal excitation of the brain, which can elicit seizures.

In the case of meperidine, this effect is a result of its primary metabolite normeperidine. For structural cogeners - fentanyl, sufentanil, and alfentanil - large single doses have produced tonic-clonic activity after epidural or intrathecal administration. I hope this clarifies the issue.

Edward C. Benzel, MD
Doctor Richeimer has provided an excellent overview of the mechanism of action, as well as the risks and benefits associated with narcotic medication. He has pointed out the limitations of such medication. One cannot expect narcotic medication to relieve 100% of any pain. Furthermore, the negative effects of narcotics, such as tolerance, may outweigh its potential benefits in most chronic pain situations. Therefore, the use of narcotics in such situations must be carefully considered.
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