The origin of opium and its use can be traced back to as far as 3400 BC in Mesopotamia; the region now called Iran and Iraq. It was a very profiting trade commodity at the period. From there it spread to Egypt and Asia. There is a wide range of drugs described as opiates. They were described as valiums but now as a term for abused drugs. They are naturally occurring drugs containing nitrogen compounds which are physiologically classified as poisonous’ Codeine and morphine are quick examples of opiate drugs. These are drugs used for the treatment of unmanageable pain. An opioid is a term or word used for drugs that are opioid receptors. Note, narcotic is derived from the Greek word for stupor. It was a term for the description of the medications for sleep impairment. Recently, it is used as a legal term to describe drugs that are abused.


In simple terms, opioids activate opioid receptors which are transported through the central nervous system (CNS) in the nuclei of the tractus solitaries, thalamus, substantiagelatinosa (PG), a periaqueductal gray area (PAG) and the cerebral cortex of the spinal cord. They are stimulated by endogenous peptides (endorphins, dynorphins, and enkephalins) whichare produced in response to noxious stimulation

These receptors are identified as:

Note, they are named based on their prototype agonists using Greek letters.

  • MOP (mu (µ) opioid peptide receptor). It’s an agonist receptor found primarily in the brain stem and media thalamus. They are known to be responsible for supraspinal analgesia, sedation, euphoria, decreased gastrointestinal motility, physical dependence, and respiratory depression.
  • KOP (kappa (k) opioid peptide receptor). It’s an agonist ketocyclazocine. They are found primarily in the limbic and other diencephalic areas, brainstem and spinal cord. They are identified to be responsible for spinal analgesia, dyspnea dependence, sedation, dysphoria and respiratory depression.
  • DOP (delta (ò) opioid peptide receptor). It’s an agonist delta-alanine-leucine-enkephaline. They are found more in the brain. Scientists are still studying their effects. They are assumed to be responsible for psychomimetic and dysphoric effects.
  • Sigma (Sigma (ó) agonist N-ally Inno metazocine). They are responsible or psychomimetic effects, dysphoria, and stress-induced depression. Sigma has not been considered as an opioid receptor anymore. It is still the target site for phencyclidine (PCP) and its analogs.
  • NOP (nociceptinorphanin FQ peptide receptor). They were identified in 1985 to have stronghyperalgesic effects. They have little semblance to the MU receptors. They are antagonists. They are likely to be antidepressants and analgesics.


There are four chemical classes of opioids:

  • Phenanthrenes are the prototypical opioids. The presenceof a 6-hydroxyl may be associated with ahigher incidence of nausea and hallucinations.For example, morphine and codeine (both with6-hydroxyl groups) are associated with more nauseathan hydromorphone and oxycodone (whichdo not have 6-hydroxyl groups). Opioids in thiscluster include morphine, codeine, hydromorphone, levorphanol, oxycodone, hydrocodone, oxymorphone, buprenorphine, nalbuphine, andbutorphanol.
  • Benzomorphans have only pentazocine as a member of this class. It is an agonist/antagonist with a high incidence of dysphoria.
  • Phenylpiperidines include fentanyl, alfentanil, sufentanil, and meperidine. Fentanyl has the highest affinity for the mu receptor.
  • Diphenylmethanesinclude propoxyphene and methadone.


Note, opiates ( drugs) occur as agonists, partial agonists, and antagonist. However, the most of the commonly acquired opioids are agonists. Agonist act by stimulating the opioid receptors: The Central Nervous System (CNS), Cardiovascular System, The Respiratory System, Gastrointestinal System, Endocrine System

  • They act as sedatives, resulting indrowsiness and loss of concentration.
  • As analgesic, effective in the relief of pain
  • It causes restlessness and a sense of ecstasy
  • It can cause hallucinations
  • Profuse sweating
  • Restlessness
  • Joint pains
  • Nausea and vomiting
  • Increase level of salivating
  • Arthritis
  • Irritability
  • Vomiting and diarrhea
  • Chest pain and excessive heart beat or racing.




There so many drugs classified as opiate drugs with the broader name of opium. Codeine, morphine are opioids, heroin is another derivative of the family. Opiates can either be taking by smoking, snorted, by injection, and it can also be inhaled (chasing). It all depends on the user’s convenient method; they all produce the same effect. However, the injection has the fastest effect.


Numerous factors, both individual and the immediate environment, influence whether a particular person who experiments with opioid drugs will continue taking them long enough to become dependent or addicted. For some individuals, the capability to provide intense feelings of pleasure is a critical reason for staying on the drug. When heroin, oxycodone, or any other opiate travels through the bloodstream to the brain, the chemicals attach to specialized proteins, called mu-opioid receptors, on the surfaces of opiate-sensitive neurons(brain cells). The linkage of these chemicals with the receptors triggers the same biochemical brain processes that reward people with feelings of pleasure when they engage in activities that promote basic life functions, such as eating and sex. This process is how addiction starts, and this is also the challenge when treating patients or drug addicts to isolate the natural occurring feeling from the drug induced feeling.Opioids are prescribed therapeutically to relieve pain, but when opioids activate these reward processes in the absence of significant pain, they can motivate repeated use of the drug simply for pleasure. Note, this is when an addict induces the feeling by the utilization of these drugs.

One of the brain circuits that are activated by opioids is the mesolimbic (midbrain) reward system. This system generates signals in a part of the brain called the ventral tegmental area (VTA) that result in the release of the chemical dopamine (DA) in another part of the brain, the nucleus accumbens (NAc). This release of DA into the NAc causes feelings of pleasure. Other areas of the brain create a lasting record or memory that associates these euphoric feelings with the circumstances and theenvironment in which they occur. The craving for more of the drugs is excited by these longing.

Note, in the early stages of abuse, the opioid’s stimulation of the brain’s reward system is a primary reason that some people take drugs repeatedly. However, the compulsion to use opioids builds over time to extend beyond a mere drive for pleasure. This increased urge is related to tolerance and dependence.


Addiction to opioids has substantialadverseconsequences like every other narcotic, not just on the individual but at the family level, social and the general public. Drug addiction mostly is associated with the continuous and uncontrollable use of drugsto the point of fatality. There is a wide range of drugs that fall under the opioids classification. These drugs occur naturally and are synthetic or semi-synthetic. Some of which are morphine and codeine. These drugs could be obtained clinically and used under medical supervision for the cure and management of different levels of unmanageable pain. Opioids mimic the natural opioid substances produced by the brain thus making the abuser glued and dependent on the introduced substance. The brain embraces theseintroducedelements not recognizing them as artificial agents. The after effect is what the addict suffers: physical and emotional changes and imbalance, mental and psychological malfunction.


  • Neglect of family and responsibilities
  • Battering and abuse of wife and children
  • Divorce
  • Neglect of domestic responsibilities
  • Aggression
  • Tiresome care for addicted family members
  • Financial losses
  • Stigma
  • Untimely death


  • A rise in the number of HIV and Hepatitis cases as a result of theuse of infected syringes by adrug addict, especially when they take it in a group or share the fix.
  • A rise in the rate of crime linked to citizens that are influenced by drugs. Also stealing to raise money for the next fix.
  • A rise in the rate of mental cases and premature death
  • A toll on budgetary allocation for treatment and rehabilitation.


Statistics show that the abuse of opiate drugs is on the rise daily. This daily rise has given concern to stakeholders in the society, especially in the health sector. Treatment for opiate addiction is costly and energy sapping, on this note, medical caregivers have advocated that the treatment should not be given free of charge. Against this development, the American Society of Interventional Pain Physicians (ASIPP) and the American Psychiatric Association (APA) in a communiqué have given guidelines for the treatment of addicts.

One of the methods for the treatment of opiates is the Methadone Maintenance Treatment developed in the 1930s by a German scientist for the treatment of addicts under rehabilitation. It ‘s hard to treatdrug addicts without them still craving for it, a dose of the MMT satisfies the patient and also serves more as a curative therapy. The treatment can span up to fifteen years, but the beauty of it is that it does not have identifiednegative effect on the patient.

Treatment with methadone requires a daily dosage of the drug; this implies that the patient visits the center daily to be administered with the daily intake. There are cases of stable and compliant patients being trusted to take home some doses, thus reducing the stress of daily visits to the center


  • Feelings of being stigmatized
  • Turning to a recluse
  • Finding it difficult to reintegrate into the society
  • Becoming a responsibility and burden to the family and the community at large