Chapter 34: Neurotoxics

**Neurotoxics**

the poisons acting on the nervous system.

Somniferous Poisons

These poisons  produce analgesia and sleep and are often used therapeutically, e.g. opium and its derivatives, pethidine, etc.

Inebriant Poisons

These are poisons that produce excitement and narcosis

Deliriant Poisons

These are poisons which produce well-marked deliriant or confusional stage, e.g. Datura, Belladonna, Hyoscyamus, Cannabis, Cocaine, etc.

Spinal Neurotoxics

These are poisons, which act primarily on the spinal cord, e.g. Nux-vomica, and its alkaloids, gelsemium.

Peripheral Neurotoxics

These are poisons, which act especially on the end plates of the motor nerve terminals, e.g. hemlock, curare, conium, etc.

**Opium**

_____ is a grey mass with bitter taste, obtained on drying the milky latex of unripe seed capsule of poppy plant, Papaver somniferum.

**Dionin**

 It is being used as a cough sedative in intractable cough, as it depresses the cough center.

**Stage of Excitement**

This stage chiefly due to the initial stimulation of CNS and includes sense of euphoria, a pleasurable feeling, hallucination and convulsions, especially in children.

**Stage of Depression**

In this stage the victim presents with weariness, weakness, headache, giddiness, heaviness in limbs, urge to sleep, itching of skin and constricted pupils (pinpoint pupils).

**Stage of Narcosis**

As the time passes, the victim from the stage of stupor goes into the stage of narcosis/deep sleep, which leads to further manifestations.

Naloxone

a drug of choice today and administered intravenously in a dose of 1.2 mg for an adult and 0.4 mg for a child. Single dose is usually short-lived and hence repeated every 15 minutes

**Naltrexone**

a long acting opiate antagonist, which can be administered orally. It is usually used for treating opiate addiction. It is administered in a dose of 50 mg/day orally, for several weeks or months.

**Nalmefene**

a naltrexone derivative with a longer duration of effect compared to naloxine in acute poisoning, given intravenously.

**Morphinomania**

Regular use of opium for painful conditions results in addiction.

**Pethidine**

An opioid, narcotic analgesic drug, which is a synthetic derivative of opium.

**Alcohol**

An inebriant cerebral neurotoxic poison; classified as sedative and hypnotic.

**Monohydroxy alcohols**

* It has only one hydroxyl group and includes:
* Ethyl alcohol, methyl alcohol, isopropyl alcohol, isobutyl alcohol, & amyl alcohol.

**Dihydroxy alcohols**

These have two hydroxyl groups and often called as ***glycols***.

**Trihydroxy alcohols**

These are not really alcohols, but their derivatives, such as the propane derivative, glycerol or glycerin.

ethyl alcohol

In a pure form ______ is transparent, colorless, volatile liquid, having a spirituous odor and burning taste. It is both water-soluble and lipid soluble.

Ethanol

_____ is obtained by fermentation of sugars, molasses, grains, fruit juices and starch. It is a complex enzymic process.

**Alpha**

Before the abuser develops psychological dependence on alcohol.

**Beta**

 Long-continued alcoholism develops cirrhosis, but no psychological dependence.

**Gamma**

Alcohol abuser goes on increasing, resulting in physical and social problems.

**Delta**

Long continued abuse which can not be abstained, will lead to serious physical complications.

**Epsilon**

The abuser develops a habit of dipsomania when he technically drinks to death.

**Reactive**

The victim drinks alcohol and seeks relief from psychological stress and strain.

**Essential**

It is he who has got a drink for inherent genetic or biological factors but not for any psychological or cultural one.

**Symptomatic**

Who drinks for long-standing psychological illness, psychosis/severe depression.

Common Abstinence Syndrome

The syndrome complex comprises manifestations such as tremors in the hands, legs, and trunk. He/she will present with a mental state of extreme emotional disturbance (agitation), sweating, nausea, headache, and insomnia.

alcoholic beverages

They are mixtures of absolute ethyl alcohol, water and congeners formed during fermentation process as in most of the ______; exception being in wine and brandy wherein the congener is methyl alcohol.

Proof spirit

It refers to a standard mixture alcohol and water of relative density.

Alcoholic Hallucinosis

The person starts seeing objects with distorted shape and their shadows moving. He/she will complain of hearing some one shouting at him or snatches of music, etc.

Alcohol Seizures

These comprise of clonic-tonic movements, with or without loss of consciousness. These manifestations appear within 6 to 48 hours of either cessation or precipitous decline of alcohol intake.

Alcohol Ketoacidosis

This is found to develop with sudden withdrawal of or heavy drinking of alcohol. Gastritis or pancreatitis, which has lead to sudden reduction in alcohol intake, might be the other cause.

**Delirium tremens**

**_______** is medicolegally important toxicological problem as it has an element of unsoundness of mind due to acute insanity associated with chronic alcoholism, is the most dangerous complication of alcoholism.

Wernicke-Korsakoff Syndrome

This is a rare form of withdrawal syndrome, which is a combination of Wernicke’s encephalopathy and Korsakoff’s psychosis.

**Wernicke’s encephalopathy**

an acute form, characterized by drowsiness, amnesia, ataxia, peripheral neuropathy, horizontal nystagmus, and external ocular palsies.

**Korsakoff’s psychosis**

When the recovery from this is incomplete, a chronic amnesic syndrome develops called **________**, which is characterized by impairment of memory and confabulations (falsification of memory).

**Alcohol Anonymous**

* A self-support organisation that plays a vital role. 
* This organisation has a base at USA and started as early as in 1935, has more than 35,000 groups all over the world. 
* There is no membership fees to join AA. 
* The only requirement to get the membership is the ‘desire to stop drinking’

**Carbamazepein**

It has been found useful in treating alcohol withdrawal, as well as delirium tremens. It does not require any adjunctive medication. It also offers advantage of rapid return to work or early induction into an alcoholism treatment program.

**Chloromethiazole**

 This is a drug of choice in Britain for alcohol withdrawal. It has hypnotic, anxiolytic, and anticonvulsant properties. It is given in a rapidly tapering dose schedule for 6-7 days. It is also known that alcoholics rapidly become dependent to this drug.

**Clonidine**

Preliminary report suggests use of clonidine in a dose of 60-180 microgram/hour intravenously with gammahydroxybutyric acid in a dose of 50 mg/kg orally is useful in withdrawal syndrome symptoms.

Methyl alcohol

_______ is colorless, clear, volatile liquid with a characteristic odor (felt to be similar to that of ethyl alcohol) and a bitter taste.

It is rapidly absorbed through the stomach and intestines, and also through the lungs and skin.

Aversion Therapy

Usually needs hospitalization for a period of several days, under close medical supervision. Effective tackling of insatiable craving for alcohol is to be achieved here by deterrent measures.

Isopropanol

______ is an inebriant neurotoxic substance. A colorless, clear, volatile liquid with aromatic odor and a burning bitter taste, mainly now used as an industrial solvent. It can be an ingredient of antifreeze, liquid detergent, paint and varnish remover, racing motor fuel.

Ethylene glycol

Its toxic action is mainly due to the metabolites-glycolic acid, lactic acid and oxalic acid.

Chloroform

* It is a heavy, colorless, volatile liquid with a strong odor and a burning sweet taste. 
* It acts as an anesthetic and respiratory depressant.
* ***Fatal dos*****e**: 30 ml by mouth (>0.04% in blood).
* ***Fatal period***:  30 minutes.

Ether

* A colorless, volatile, highly inflammable liquid with penetrating ethereal odor and sweetish pungent taste.


* Ether acts as an anesthetic and respiratory depressant.
* ***Fatal dose***: 30 ml by mouth. 
* ***Fatal period:*** May be immediate due to syncope during anesthesia—rarely.

Barbiturates

_______ are basically derived from barbituric acid, the oldest being veronal barbitone.

benzodiazepines

Death by ___________ alone in the absence of other significant toxicological agents or pathology is uncommon, although alone can cause death in absence of significant natural diseases or advanced age.

Pesticide

any substance or mixture of substances intended for preventing, destroying or controlling any pest (insects, rodents, fungi, mites, ticks, mollusks, weeds, and herbs) including vectors of human or animal diseases.

Organochlorines

* Used as insecticide agents at home, garden and agricultural fields, which were popular once, now they are phasing out all over the world due to its cumulative effect and health hazards.
* These are insoluble in water. DDT is a volatile solid (slow of course) having a faint odor.

Alkyl compounds

hexaethyl tetraphosphates (HETP), tetraethyl pyrophosphates (TEPP), octamethyl pyrophosphoramide (OMPA), malathion, cystox, dipterex, etc.

Aryl compounds

parathion, para-oxon, methyl parathion, chlorothion, diazinon, (Tick-20), etc.

Agriculture insecticides (highly toxic)

OMPA, TEPPParathion, Phosdrin, Disyston, etc.

Animal insecticides (moderately toxic)

Ronnel, Coumephos, Trichlorfon, etc.

Household insecticides (low toxic)

Malathion (Kill bug, Cimexol, Jyothi oil, Bugsolin-20, etc.), Diazinon (Tick-20), Vapona, etc.

Atropinisation

tropine is administered immediately to save life and continued till the achievement of the state of ______.

Organophosphorus Insecticides

These most popular insecticides, often involved in serious/fatal human poisoning incidences. Victims are usually children, farmers and unskilled laborers.

Pralidoxime

It brings about anticholinergic “atropine-like” effects resulting in freeing and reactivating cholinesterase enzymes by cleaving phosphorylation

Furosemide (Lasix)

It is given in a dose of 40 to 160 mg IV to alleviate the pulmonary congestion remaining after full atropinization.

Carbamate

______ poisoning exhibits a similar clinical picture to organophosphate toxicity.

Carbamate

______ compounds temporarily bind cholinesterase for approximately 6 hours with no permanent damage.

**Aluminum phosphide**

**______** is a solid fumigant pesticide, widely used as a grain preservative in India. It is marketed as greyish-green tablets.

**Naphthalene**

**______** is an insecticide, a solid volatile substance obtained from the middle fraction of coaltar distillation and has chemical properties similar to benzene.

Datura plant

It is about 1.2-2 meter height with widely spread branches. Fruit is about the size of a walnut, spherical and covered with sharp spiny projections.

* Each fruit on an average contains about 500 seeds. They are yellowish-brown in color and resemble chilly seeds. The leaves are dark green, alternate and broadly ovate in shape.

Cannabis

It is classified as a mild hallucinogen or a sedative or a narcotic. In fact the drug is believed to produce all these effects in various individuals in a different way.

**Ganja**

It is the resinous mass composed of small leaves and bracts of inflorescence (flowering tops) from female plants, which contains about 25% of the active principle. It is usually mixed with tobacco and smoked in pipe.

**Charas**

It is also called as **Hashish** and is the purest form of cannabis. It is the dried resinous exudate from the flower tops.  It is dark green or brown in colo, and contains 25 to 40% of the active principle.

**Bhang**

Also called as **siddhi, patti** or **sabji** is the crudest form of cannabis. It is prepared as a decoction of dried mature leaves and flower stems, and contains 15% of active principle. It is usually consumed in the form of a beverage.

**Marijuana**

the most common illicit drug used. It refers to any part of the cannabis plants or its extract that is used to induce psychotomimetic or therapeutic effects.  It is eaten alone or as a part of confection, or drunk in beers, or some other beverage, or smoked in pipes or after being rolled into cigarettes.

Cannabis addiction

 a chronic poisoning state; resulting from continued use of the drug in any form and is characterized by—anorexia, loss of weight, weakness, tremors, impotence and moral deterioration

Hashish insanity

A cannabis addict is often found to suffer from mental disorders such as hallucinations and delusions of a persecution nature, presention with an irresistible desire to destroy life and property willfully or commit homicide out of sexual jealousy of which there will be no recollection afterwards.

alkaloid

It is a complex substance with a nitrogenous base that behaves like alkali and unites with acid-forming salts.

Morphine

In its pure form is a white crystalline powder, having a bitter taste, freely soluble in alcohol and water.

Codeine

It is a white, crystalline powder, with a bitter taste, is chemically CH3 morphine, and is soluble in water. Its principal action is depression of the cough center.

Thebaine

It is a convulsant poison that can produce tetanic convulsions, resembling tetanus/strychnine.

Heroin

Previously used as a sedative, but for its narcotic and addiction-forming effect its production has been banned. It is considered as health hazard for younger generation, all over the world.

**Cocaine**

**______** is an alkaloid obtained from the dried leaves of coca plant (Erythroxylon coca).

**Cocaine hydrochloride**

**________** is a white, colorless, crystalline substance, which has a bitter numbing taste. It is slightly soluble in water, but freely soluble in alcohol.

**Crack cocaine**

**______** is a cocaine preparation which has been separated from its hydrochloride base (free base) by adding baking soda and water, followed by heating and then drying, which can be mixed with tobacco and smoked.

Cocainism

Chronic cocaine poisoning, cocainophagia, cocainomania, cocaine addiction.

Magnan’s symptom

a type of tactile hallucination making the addict feel like insects (bugs) are crawling under the skin of the part of their body. He or she may even complain of presence of sand grain under the skin.

Strychnine

* A spinal poison.
* Seeds are the toxic part of the plant. These seeds are grayish brown in color, and measure about 2.5 cm in diameter 0.65 cm in thickness, and are discoidal in shape with central depression.