Atropine - a plant alkaloid
Atropine (Atropine) - a widely known drug that is naturally occurring - is found in some plants. Despite its active use in medicine, atropine is a dangerous substance - it is easy for them to poison themselves, especially for children. For this you need to eat the belladonna berries growing everywhere.
So what is it - atropine, how does it work and where does it apply? How to determine the poisoning them and what to do? What antidotes exist? Let's figure it out.
Atropine - a dangerous alkaloid
What is atropine? This substance belongs to the group of alkaloids. Alkaloids are heterocyclic bases containing a nitrogenous group, present in some plants and exhibiting biological activity. In other words, alkaloids are compounds that can somehow affect a living organism. In one plant may be several alkaloids.
Such an alkaloid is found in the belladonna (belladonna), henbane, dope, scopolia, and other plants of the nightshade family. Atropine (lat. Atropinum) is a natural poison, but in small doses it is used for medical purposes.
The chemical structure of atropine refers to crystalline powders. It is amorphous, colorless, odorless. The substance has two isomers. The levogyrate is called hyoscyamine, which is much more active than atropine. It is hyoscyamine and is found in plants. But this substance is unstable and during chemical excretion it turns into atropine.
Mechanism of action of atropine
This alkaloid disrupts the conduction of a nerve impulse by blocking receptors. That is, it competes with the natural substance of the body (acetylcholine) in its ability to bind to sensitive endings on the path of an impulse. There are several types of sensitive endings: M and H. Atropine blocks only M-receptors.
The mechanism of action of atropine is that it binds to specific formations of the nerve cell instead of acetylcholine. Accordingly, the transmission of nerve impulses is blocked. Depending on which organ system acts, atropine causes different effects.
- Relaxation of smooth muscle cells. This effect of atropine is observed in the bronchi (expansion), the gastrointestinal tract, the bladder. Muscle relaxation in these organs is caused by inhibition of impulses from the parasympathetic nervous system.
- Reduced secretion of the secretion glands, namely: bronchial, digestive, sweat, salivary, lacrimal. The mechanism of suppression of bronchial and digestive secretions is due to the blockade of parasympathetic, and salivary, tears and sweat - on the contrary, the blockade of the sympathetic nervous system.
- Mydriasis (dilated pupils). The circular and radial muscles of the iris are antagonists and balance the action of each other. Atropine binds to the M3-cholinergic receptors of the circular muscle of the iris, it relaxes, while the radial muscle is tense, its action prevails and the pupil expands.
- Accommodation paralysis (adaptation of the eye to changes in external conditions for a clear perception of objects located at different distances). Atropine relaxes the ciliary muscle of the eye and flattens the lens, which causes farsightedness.
- Increased heart rate due to inhibition of the parasympathetic effect on the sinoatrial node. But sometimes an increase in heart rhythm can be preceded by bradycardia (decrease in heart rate), this is due to the stimulation of the vagal centers.
- Improves atrio-ventricular conductivity.
- It affects the vessels, but only in very large doses. In doing so, they expand, the skin of a person turns red. Atropine does not dilate blood vessels in small doses, but it still binds to receptors. Therefore, drugs that dilate the blood vessels may not work, since the sensitive endings with which they should have been contacted are already occupied by atropine.
Where is atropine used
There are 2 drugs, the main active ingredient of which is belladonna alkaloid:
- "Atropine" - pills;
- "Atropine sulfate" - 0.1% injection and 1% eye drops.
The drug is widely used in clinical practice. The use of atropine is practiced in gastroenterology. He is appointed by:
- in case of ulcers of the duodenum and stomach in order to suppress gastric secretion;
- spasm of the pyloric sphincter of the stomach to relax it;
- gallstone disease and inflammation of the gallbladder in order to expand the ducts and drainage of stagnant bile;
- with bowel spasms;
In other branches of medicine, atropine is used:
- spasms of the bladder;
- bronchial asthma, as a means of eliminating bronchospasm;
- to reduce the secretion of glands: salivary, sweat, tears;
- in reducing the pulse associated with the tone of the vagus (should be prescribed carefully, as, perhaps, a short-term increase in bradycardia);
- in anesthesiology for sedation and anesthesia, during surgery, intubation, to eliminate laryngospasm and bronchospasm, reduce salivation;
- radiography of the stomach to reduce its tone during the study;
- with increased sweating.
What is atropine used for? This drug is an antidote for poisoning with organophosphate compounds, including poisons, overdose with cholinomimetic and anticholinesterase drugs. In addition, atropine is used in ophthalmology as a drug that dilates the pupil in the study of the fundus.
Overdose and poisoning
Atropine can be used intramuscularly, orally, intravenously, subcutaneously, or as an eye drop. He is administered orally from 0.25 to 1 mg 1–3 times a day. This variation in dosage is explained by the individuality of each organism and the amount of the drug must be selected individually. Intravenous, intramuscular, subcutaneously in the same dosage, but 1-2 times a day. Atropine in the form of eye drops is instilled 1–2 drops 3 times a day. To expand the pupil for the study - 1-2 drops 1-2 times. The maximum single dose of atropine 1 mg, the maximum daily - 3 mg.
Atropine poisoning can be accidental or targeted. The severity of the manifestations depends on it. Basically, poisoning occurs when the fruits of the family of ashes are accidentally consumed. Children are in the main risk group.
The toxic effect of atropine begins to manifest itself 40–60 minutes after administration. Depending on the dose, there are mild, moderate and severe degrees of poisoning. First of all, the substance affects the brain structures, causing psychosis, impaired coordination, hallucinations. Then the heart and lungs suffer.
An overdose of atropine is detected by the following symptoms:
- decreased sweating;
- redness of the mucous membranes;
- heart palpitations up to arrhythmia;
- nausea, vomiting;
- tremor of limbs;
- hoarseness, difficulty swallowing;
- skin redness;
- visual impairment;
- increased breathing;
- convulsive syndrome.
Such symptoms may occur with an unintentional overdose.
Purposeful poisoning has more serious symptoms:
respiratory muscle paralysis;
- decrease in heart rate, atrial or ventricular fibrillation.
The dose of atropine, which is fatal, is 100–150 mg or 1–1.5 mg per 1 kg of body weight. In children, the dose is less. In terms of belladonna berries - 3-6 pieces can be fatal in a child. Death usually occurs no earlier than 5 hours after poisoning.
The consequences of poisoning can be not only death. With a long stay in a coma, irreversible organic changes can occur in the brain, leading to impaired intelligence and memory.
Treatment of poisoning begins with washing the stomach with water, potassium permanganate, or saline laxative solutions. Immediately you need to give the poisoned antidote atropine. It may be:
- 0.1% solution of aminostigmine 2 mg;
- 0.05% solution of galantamine (the drug "Nivalin") 2 mg.
Repeat administration of antidote after 90 minutes. The more severe the poisoning, the less frequently the antidote is administered. In severe cases, it can be entered every 15 minutes.
Aminostigmine quickly restores consciousness, eliminates psychomotor agitation and hallucinations. It is used not only to treat overdose, but also to prevent recurrence of coma.
There is another atropine antagonist, alkaloid pilocarpine. Drugs based on it (eye drops) are used in ophthalmology to reduce intraocular pressure. Atropine, dilating the pupil, can cause glaucoma. With a strong increase in pressure inside the eye, retinal detachment may occur. Therefore, in case of poisoning by plants or preparations containing atropine, pilocarpine must be entered immediately according to the following scheme:
- every 15 minutes, 1 drop in each eye for an hour;
- the next 2–3 hours drip 1 drop in 30 minutes;
- then 4–6 hours - drop by drop every hour;
- then 3–6 times a day drop by drop until the relief of high intraocular pressure.
Let's sum up. Atropine is an alkaloid of plants from the nightshade family. It is an anticholinergic drug actively used in medicine. It is used in gastroenterology, pulmonology, cardiology, ophthalmology, anesthesiology, toxicology, and urology. Serious overdose of this drug can occur with the occasional use of berries of Solanaceae plants or a large amount of the drug. The clinic of poisoning depends on the dose taken. Death comes from taking 100 mg of atropine. There are specific antidotes that need to be taken immediately - these are aminostigmine and galantamine. They are administered intravenously repeatedly. Consequences of atropine poisoning can be coma, impaired intelligence and memory.