Opium Poisoning

 

Opium

Papaver Sominferum grows through­out India, but its cultivation is banned except

 on license obtained from the Central Government, for growing the plant strictly for

 the purpose of pharma­ceutical industry. Government Opium factory is situated at

 Gazipur, U.P.

Mechanism of action:

Opioids act via receptors on cell membranes. Opioid receptors are coupled to G

 proteins and are thus able to effect protein phosphorylation via the second

 messenger system and change ion channel conductance. Presynaptically, activation

 of opioid receptors inhibits the release of neurotransmitters involved in pain,

 including substance P and glutamate. Postsynaptically, activation of opioid

 receptors inhibits neurons by opening potassium channels that hyperpolarize and

 inhibit the neuron.

Currently, there are five proposed classes of opioid receptors: μ, δ, κ, σ, and ε. μ

 receptors are the main functional target of morphine and morphine-like drugs;

 they are present in copious quantities in the PAG matter in the brain and the

 substantia gelatinosa in the spinal cord. Mu (μ) receptors are also found in the

 peripheral nerves and skin. Activation of μ receptors results in analgesia, euphoria,

 respiratory depression, nausea, vomiting, and decreased gastrointestinal (GI)

 activity, as well as the physiological syndromes of tolerance and dependence. Two

 distinct subgroups of the μ receptors have been identified: μ1, found supraspinally,

 and μ2, found in the spinal cord. The μ1 receptor is associated with the pain-

relieving effects of opioids, whereas μ2 receptors mediate constipation and

 respiratory depression.

The δ receptor has central and peripheral distribution like the μ receptors. Studies

 have shown that δ-opioid agonists can provide relief of inflammatory pain and

 malignant bone pain. Meanwhile, peripherally restricted κ-opioid agonists have

 been developed to target κ-opioid receptors located on visceral and somatic

 afferent nerves for relief of inflammatory, visceral, and neuropathic chronic pain.

The endogenous ligands, noticeably the products of the three peptides genes

 enkephalin, β-endorphin, and dynorphin do not appear to have specificity toward

 these multiple opioid receptors. Initially, enkephalin and β-endorphin have been

 the prototypic ligands for the δ- and μ-opioid receptors, respectively. Dynorphin,

 with the positively charged amino acids, arginine and lysine, has been shown to

 preferentially interact with the κ-opioid receptor.

Location and clinical effects of opioid receptors
Receptors	Locations	Clinical effects
μ	Mesenteric plexus, brain, spinal cord and sub mucosal plexus	Anagesia, changes smooth muscles tone, sedation, mood alteration, nausea and vomiting
𝛿	Mesenteric plexus and brain	Decrease colonic transit time
К	Mesenteric plexus, brain and spinal cord	Central analgesia, Decrease colonic transit time, visceral nociception antagonist

Various forms of Opium:

(i) Opium is the dried juice of Papaver somni­ferum, and dry capsule is used as a

 sedative fomen­tation and poultice

(ii) Opium when fresh is plastic and internally moist, coarsely granular or smooth.

 It is reddish brown to deep brown, hard and brittle

(iii) Post ka doda contains 0.1-0.3% morphine. The morphine con­tent of the opium

 varies from 9-14 %, but when the morphine content is 10% it is known as stan­dard

 opium

(iv) Poppy seeds (Khas khas): These are white, harmless demulcent, nutritive and

 used in various food preparation

Opium alkaloids:

Phenanthrene and Isoquinoline.

The phenanthrene group has following derivatives

(i) Morphine (9-14%) (ii) Codeine (2-4%) (iii) Thebaine (0.5%).

The isoquinoline group are (i) Papaverine (1%) (ii) Narcotine (6%).

Signs and Symptoms- Three stages are there, excitement, stupor and stage of

 narcosis.

An opiate is a substance derived from opium and the term opioid is used for all

 substances both natural and synthetic which bind to opioid receptors in brain.

Opioid poisoning is characterised by miosis (pinpoint pupil), respiratory

 depression (bradypnea/apnea) and central nervous system depression (sedation or coma).

Fatal Dose: 2 gm opium, 0.2 gm morphine

Fatal Period: 6-12 hours

Marquis test: A presumptive test that gives a variety of colour changes with a

 range of compounds. It is particularly useful for detecting opiate alkaloids and for

 amphetamines and methamphetamine. Marquis reagent is a mixture of methanal

 (formaldehyde) solution in water with sulphuric acid. Amphetamines give an

 orange red colour, methamphetamine gives an orange colour and with morphine, a

 violet colour is produced. The mechanism involves attack of the aldehyde a

 substituted aromatic ring to form a carbocation. Further reaction forms a coloured

 dimer of the original molecule.

Autopsy Findings

(i) Evidence of drug abuse in the form of injection prick marks, abscesses and old

 scars can be there

(ii)Signs of asphyxia are present

(iii)Froth comes out from the mouth and nostrils

(vi)Blood is dark and fluid

(v) In the stomach contents, lumps of opium may be present

(vi)Lungs are congested

Medico legal aspects

(i) Opium is the commonest drug used for suicidal purposes.

(ii)Due to its colour and smell, it is rarely used for homicidal poisoning

(iii)To poison the cattle, it is mixed with jaggery.

(iv)It withstands putrefaction and can be detected after a long time

(v) Accidental poisoning can occur at times when the labourers give opium to their

 children while going for work.

#opium poisoning #opium