OPIOIDS – INTRODUCTION
Opioids have similar properties to the opium from which they are derived. One of the main functions of opioids is to produce sedation and pain relief and they have been used for pain relief over thousands of years. Opioids are essentially chemicals that bind to opioids receptors present in the brain and central nervous system and the gastrointestinal tract to stimulate their effects.
OPIOIDS – INDICATION
Opioids are a class of drugs chemically similar to alkaloids found in opium poppies. Historically they have been used as painkillers, but they also have great potential for misuse. Repeated use of opioids greatly increases the risk of developing an opioid use disorder. The use of illegal opiate drugs such as heroin and the misuse of legally available pain relievers such as oxycodone and hydrocodone can have serious negative health effects.
OPIOIDS – INFORMATION
Opioids are medications that relieve pain. They reduce the intensity of pain signals reaching the brain and affect those brain areas controlling emotion, which diminishes the effects of a painful stimulus. Medications that fall within this class include hydrocodone (e.g., Vicodin), oxycodone (e.g., OxyContin, Percocet), morphine (e.g., Kadian, Avinza), codeine, and related drugs. Hydrocodone products are the most commonly prescribed for a variety of painful conditions, including dental and injury-related pain. Morphine is often used before and after surgical procedures to alleviate severe pain. Codeine, on the other hand, is often prescribed for mild pain. In addition to their painrelieving properties, some of these drugs—codeine and diphenoxylate (Lomotil) for example—can be used to relieve coughs and severe diarrhea.
How Opioids Work
Opioid drugs work by binding to opioid receptors in the brain, spinal cord, and other areas of the body. They reduce the sending of pain messages to the brain and reduce feelings of pain.
Opioids are used to treat moderate to severe pain that may not respond well to other pain medications.
Some types of opioid drugs include:
- codeine (only available in generic form)
- fentanyl (Actiq, Duragesic, Fentora)
- hydrocodone (Hysingla ER, Zohydro ER)
- hydrocodone/acetaminophen (Lorcet, Lortab, Norco, Vicodin)
- hydromorphone (Dilaudid, Exalgo)
- meperidine (Demerol)
- methadone (Dolophine, Methadose)
- morphine (Astramorph, Avinza, Kadian, MS Contin, Ora-Morph SR)
- oxycodone (OxyContin, Oxecta, Roxicodone)
- oxycodone and acetaminophen (Percocet, Endocet, Roxicet)
- oxycodone and naloxone (Targiniq ER)
Your doctor can prescribe most of these drugs to take by mouth. Fentanyl is available in a patch. A patch allows the medication to be absorbed through the skin.
Other effects and side effects of opioids
In addition to pain relief, there are several effects mediated by opioid receptors present in the central nervous system and the gastrointestinal tract. These include:
- Sedation or drowsiness: This makes the driving and operation of heavy machinery dangerous for people on opioids.
- Suppression of cough: Opioids suppress the cough reflex in the brain leading to suppression of a cough. Opioids such as codeine have therefore long been used as cough suppressant.
- Respiratory depression: This describes suppression of the breathing mechanism in response to low blood oxygen. As blood oxygen falls and blood levels of carbon dioxide rise, there is an increase in drive for respiration. However, opioids suppress the respiratory centre and drive in the brain, potentially leading to hypoventilation.
- Constipation: One of the main side effects of opioids is constipation due to the sluggish persitalsis in the digestive tract that they cause.
- Dependence and likelihood of abuse: Use of opioids in the long term may cause dependence on the drugs leading to withdrawal syndrome when an individual suddenly stops taking them.