Introduction
Parathion is widely used as an agricultural insecticide. It has been used extensively by farmers on major crops such as wheat, fruits, vegetables, nuts, citrus fruits, alfalfa, corn, soyabean and other field crops. It is used to prevent the larvae of the pests from growing up. It even causes the eggs of the pests to die out when comes in contact with it.

Besides various portals of entry as will be described below there are high chances for some amount of the poison to get into the system through these foodstuffs we consume and cause symptoms of its effect.

Source
Parathion is prepared by the reaction of diethyl phosphorothionchloridate with sodium p-nitrophenate.

Identity
The chemical name of parathion is O,O-diethyl O-(4-nitrophenyl) phosphorothioate
And the chemical formula is given below.
Synonyms
OMS 19
E 605 - Belgium
Thiophos - USSR
SNP - France

Physical Properties
Description: Pale-yellow to dark-brown liquid at room temperature
Warning properties: Weak odor of garlic at 0.47 mg/m³; inadequate warning for acute and chronic exposures. Does not generally produce skin irritation.
Molecular weight: 291.3 daltons
Boiling point (760 mm Hg): 707ºF (375ºC)
Freezing point: 43ºF (6.1ºC)
Specific gravity: 1.27 (water = 1)
Vapour pressure: 4 x 10-5 mm Hg at 68ºF (20ºC)
Water solubility: insoluble (0.001% at 68ºF) (20ºC)
Flammability: 392ºF (200ºC)
Incompatibilities: Parathion reacts with strong oxidizers and alkaline materials.

Methyl Parathion can enter the body in three ways:
Skin Contact
Inhalation
Ingestion

Toxic Effects
Parathion, like all organophosphate pesticides, inhibits acetylcholinesterase and alters cholinergic synaptic transmission at neuroeffector junctions (muscarinic effects), at skeletal myoneural junctions and autonomic ganglia (nicotinic effects), and in the CNS. Inhibition occurs when a metabolite of parathion binds to acetylcholinesterase; thus, symptoms may be delayed after exposure. Signs and symptoms of poisoning vary according to age, dose, and concentration.

Muscarinic effects include pinpoint pupils; blurred vision; hypersecretion by salivary, lacrimal, sweat, and bronchial glands; narrowing of the bronchi; nausea, vomiting, diarrhoea, and crampy abdominal pains; urinary and fecal incontinence and slow heart rate.

Nicotinic effects include muscle twitching, cramping, and weakness. Nicotinic stimulation can obscure certain muscarinic effects and produce rapid heart rate and high blood pressure.

Central Nervous System
CNS effects are often the earliest manifestations of poisoning in adults and constitute the major signs and symptoms in children. CNS effects include irritability, nervousness, giddiness, fatigue, lethargy, impairment of memory, confusion, slurred speech, visual disturbance, depression, impaired gait, convulsions, loss of consciousness, coma, and respiratory depression.

Peripheral Nerves
Peripheral neurologic effects include muscle twitching and weakness due to inhibition of acetylcholinesterase at neuromuscular junctions.

Respiratory
Respiratory failure is the most common cause of death due to parathion poisoning. Narrowing of the bronchi and markedly increased bronchial secretions can occur. Respiratory failure results from respiratory depression coupled with paralysis of the respiratory muscles and progressive airway obstruction from bronchorrhoea. In addition, pulmonary aspiration of the hydrocarbon solvents found in many commercial preparations can cause inflammation of the lungs. Children may be more vulnerable because of relatively increased ‘minute ventilation per kg’ and failure to evacuate the area promptly when exposed.

Cardiovascular
Most exposure victims experience bradycardia, but pulse rate may be increased initially and tachycardia is more common in very severe poisoning. Irregular heart beat may occur.

Gastrointestinal
Nausea, vomiting, abdominal cramps, diarrhoea, and faecal incontinence are common manifestations, regardless of the exposure route. These are again generally the earliest symptoms to occur.

Metabolic
Profuse sweating is likely to occur and may lead to profound dehydration. This is somewhat less common in children.

Dermal
Parathion is not generally irritating, but is readily absorbed through the skin. Skin contact can result in systemic poisoning. Because of their relatively larger surface area: body weight ratio, children are more vulnerable to toxicants absorbed through the skin.

Ocular
Systemic poisoning typically causes pinpoint pupils and spasm of the muscle of visual accommodation (i.e. ciliary muscle) leading to blurred vision and aching pain in the eye. However, organophosphate poisoning may still be present without pinpoint pupils, and dilation of the pupils may even be noted occasionally. Eye irritation, if it occurs, is most likely to be caused by the hydrocarbon solvents used in commercial pesticide preparations.

Potential Sequelae
Complete recovery generally occurs within 10 days unless severe lack of oxygen has caused residual brain damage. CNS effects such as confusion, fatigue, irritability, nervousness, and impairment of memory can occasionally last for several weeks. Six to twenty-one days after acute exposure to some organophosphate compounds, onset of nerve disorders of mixed sensory-motor type may occur; peripheral nerve recovery may never be complete. It is uncertain if parathion produces this delayed polyneuropathy.

Chronic Exposure
Persistent weakness and impaired memory have been reported to occur from low-level exposures to organophosphates in the absence of acute cholinergic effects.

Carcinogenicity
The International Agency for Research on Cancer has determined that parathion is not classifiable as to its carcinogenicity to humans. However, EPA lists parathion as a possible human carcinogen.

Reproductive and Developmental Effects
Studies have been reported in which parathion was embryo-toxic and fetotoxic in rodents. There are no studies yet addressing reproductive or developmental effects in humans exposed to parathion.

Instance which mad me to prove this drug

The people who reside nearby to the FCI godowns as well the lorry drivers who load the sacs with recently processed grains into the vehicles used to get difficulty in breathing (Allergic Rhinitis & Allergic Asthma). The complaints occurred especially when the FCI people open the air tight packings of the poisonous substances like Malathion, Parathion, etc. used for the preservation of the grains.

The usual procedure is that the air tight packages of tons of grain sacks are kept for a week and then they will randomly select the sacs, which are processed and see how much quantity of poison is penetrated and stored inside the grains. If it is below that of the human tolerance rate it will be distributed or otherwise will be used as a cattle feed.

These patients (the so called victims of this poisoning) are not fully responding to the treatment. While searching for a cause I could find that this may be the maintaining factor. So I thought of testing its actual potential and introducing this medicine into the Homoeopathic field. This can be used as an antidote for those who reside near the FCI as well as all of us as it is the widely used poison for the preservation of not only grains like wheat, rice etc but also for fruits and vegetables. The latest report points that even the mineral water contains large quantity of Malathion and Parathion. So all over the world people are being under chronic poisoning unknowingly to this kind of pesticides and hence in the future this drug will be very useful as an antimiasmatic too.

The Drug proving of Parathion was conducted at JSPS Govt. Homoeopathic Medical College, Ramanthapur, Hyderabad. It was done on P.G.Students, both males and females of age group between 24-30 years.

The medicine was prepared in our Pharmacy by myself under the guidance of the Department Head. Till 6x potency it was triturated followed by succussion by jumping into 8C. Then up to 30th potency the medicine was prepared manually.

Medicine was administered after one week of ‘placebo proving’ just to screen the provers. Following that four pills four times daily were given to the volunteers till symptoms started developing. All the symptoms given below developed within 2 days. And they lasted for about 15 days except perspiration over the occipital region which alone stayed on for a month.

The symptoms observed during Homoeopathic proving are as follows. The intensity of the symptoms is indicated as the numbers superscript to the end of corresponding symptoms.

Mind
Irritability2 – shouts back with stubbornness to the core
Sadness – wants to be alone is marked
Irritable, thinks that he is correct in all aspect.
Sadness alternating with irritability 2

Head:
Left sided supra orbital headache. Pain dull and pulsating at temple.
-with feverish feeling
-stabbing pain over the left elbow and knee.
-with increased appetite and sleeplessness.
Sweating, profuse over the scalp3 with sensation of coldness over forehead
Occipital sweating3

Eyes:
Burning of the left eye

Face:
Burning in lips.

Mouth:
Apthae over the left posterior 1/3rd of the tongue & left side of inner lip which is not much painful.
Sticky salivation, not able to spit it out that much sticky in the morning while getting up.
Bad taste in the mouth after the afternoon sleep.

Stomach:
Desires ice-cream2

Rectum:
Urge to pass stool immediately after getting up.2

Chest & Back:
Sweating profuse over the neck and axilla

Sleep & Dreams:
Sleeplessness3 upto 2- 5 AM
Startling during sleep with the twitching/jerking only on right side.
Dreams of sweating but when he gets up suddenly he is not sweating.