Opioids are narcotic analgesic drugs commonly prescribed for treating severe to chronic pain. Opioids work by binding to the opioids receptors and blocking the pain signals from reaching upto the brain. Although opioids have strong analgesic and pain relieving properties, they have a strong potential to cause addiction. Mainly abused for the sense of euphoria they cause, opioids are broadly classified into four types; Natural, Semi-synthetic, Fully synthetic, and Endogenous.

Adverse Effects Include:

Prolonged exposure to opioids can cause tolerance, drug escalation, and physical dependence.

Nausea

Exposure to opioids can cause individual to experience nausea with or without vomiting. Young women are found to be at more risk of developing nausea when on opioids. Opioids particularly affect the brain and GI track that causes nausea.

Drowsiness

Opioids use is marked by events of drowsiness or sedation. Few opioid medications like morphine and diacetylmorphine (heroine) can cause strong drowsiness or sedation.

Itching

Opioids use can also result in causing itching as it releases histamines in the body. The person may experience itching as opioids binds with receptors in brain and spinal cord.

Constipation

Opioids use can result in severe constipation. The opioid induced constipation may remain for a longer time. Stool softeners and laxative use is recommended when using opioids to avoid constipation.

Respiratory Depression

Opioids cause respiratory depression in the individual as it affects the specialized respiratory neurons in the brain. A large opioid overdose can lead to asphyxia and even death due to respiratory depression.

Vomiting

Opioids affect the part of brain that controls vomiting and causes the individual to vomit.

Classification:

Opioids are classified as Natural, Semi-synthetic, Fully synthetic, and Endogenous.

Natural

Natural opioids are opiate alkaloids derived from the resin of the poppy plant. Incisions are made on the immature green seed pods of opium plants and the latex that is obtained contains opiate alkaloids. The latex is then dried and is used to prepare many drugs like thebaine, morphine, codeine, noscapine, and papaverine. Natural opioids are put to various medicinal uses as narcotic analgesic, hypnotic, and sedatives. Although the latex is used to prepare many drugs, the poppy oil and seeds are not narcotic and has various uses.

Semi-Synthetic

Semi-synthetic opioids are not naturally occurring and prepared from natural opiates. They have similar chemical structure to natural opiates. Some of the semi-synthetic drugs are hydrocodone, oxycodone, oxymorphone, hydromorphone, and diacetylmorphine (heroine). It is due to their analgesic properties that semi-synthetic opioids are used for variety of purposes. Semi-synthetic opioids are also one of the widely abused drugs.

Fully Synthetic

Fully synthetic opioids are not related to opiates and artificially manufactured. Drugs like dextropropoxyphene, fentanyl, methadone, pethidine, tramodol etc fall under the category of fully synthetic drugs. The fully synthetic drugs are prescribed for their analgesic properties to treat chronic pain. Some drugs like Fentanyl are used as an anesthetic before surgery and are 100 times stronger than morphine. Methadone is used to treat opioid addiction. Methadone can block effects of other drugs like heroine, morphine and help the person cope with withdrawal symptom.

Opioids do not have upper limit for dosage that can be taken to attain relief from pain. More is the amount of opioids taken the more is the pain relief. However, for medicinal purpose care needs to be taken to increase the dosage gradually to ensure tolerance develops to the adverse effects.