The Opioids are a class of controlled pain-management drugs that contain natural or synthetic chemicals based on morphine, the active component of opium. These narcotics effectively mimic the pain-relieving chemicals that the body produces naturally.
Opioids are the most often prescribed pain-relievers because they are so effective. Moreover, many studies have shown that opioid analgesic drugs are safe and rarely cause clinical addiction or compulsive usage if taken as directed.
Morphine, heroin, codeine and related drugs are among the opioids. Morphine is frequently prescribed to alleviate severe pain after surgery. Codeine can be helpful in soothing somewhat milder pain, as are oxycodone (OxyContin, an oral, controlled-release form of the drug), propoxyphene (Darvon), hydrocodone (Vicodin), hydromorphone (Dilaudid) and meperidine (Demerol), which is used less often because of its side effects. Diphenoxylate or Lomotil can also relieve severe diarrhea, and codeine can ease severe coughs.
Opioids act by attaching to a group of proteins called opioid receptors, found in the brain, spinal cord and gastrointestinal tract. When these drugs link to certain opioid receptors in the brain and spinal cord they can block the transmission of pain messages to the brain.
Medication for pain may be taken in a variety of ways. The preferred method is by mouth, since medication taken orally is convenient and usually inexpensive. When this method cannot be used, medication may be taken rectally or through patches placed on the skin. Intravenous methods are used only when easier and cheaper methods are not available. Patient-controlled analgesia (PCA) pumps are sometimes used to allow the patient to deliver the drug into veins, skin or the spine. Intraspinal administration is especially helpful for patients who do not respond to pain medications delivered by the other methods or who experience extreme side effects.
Patients may find that they develop tolerance to opioid pain medications and may need to have their doses increased in order to be effective. Tolerance has not been shown to lead to drug addiction in patients who take opioid drugs for medical reasons. Physical dependence on opioid pain medications does not seem to occur in cancer patients. Once the pain disappears (usually through the effective treatment of cancer), these patients can discontinue the pain medicine without difficulty.
Steady use of opioids can result in tolerance to the drugs so that higher doses must be taken to achieve the same effects. Long-term use also can lead to physical dependence—the body adapts to the presence of the drug and withdrawal symptoms occur if use is reduced abruptly.
Symptoms of withdrawal can include muscle and bone pain, insomnia, vomiting, cold flashes with goose bumps ("cold turkey"), involuntary leg movements, diarrhea and restlessness.
Adjuvant Drugs: Other drugs may be given with the pain medication for increased effectiveness. These drugs include corticosteroids, anticonvulsants, antidepressants, local anesthetics and stimulants.
Opioids are only safe to use with other drugs under a physician's supervision. It is wise to avoid using them with alcohol, barbiturates, antihistamines or benzodiazepines. These drugs slow down breathing, and their combined effects could result in life-threatening respiratory depression.
