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Acute atropine poisoning: signs, treatment
Last reviewed: 04.07.2025
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Atropine is widely used in medicine on its own in the form of sulfate and is a part of many complex drugs - anti-asthmatic (Solutan, Franol), antispasmodics (Besalol, Spazmoveralgin) and some others. It is used in ophthalmology and psychiatry. Atropine poisoning occurs as a result of accidental or intentional overdose of this substance. The effect of toxic doses is explained by the ability of this substance to cause atropine delirium - a condition similar to narcotic, with impaired consciousness (hallucinations and delirium), which can even lead to death as a result of respiratory paralysis.
Atropine is chemically isolated from plant materials. Its predecessor, an even more active natural alkaloid hyoscyamine, is found in many poisonous plants of the nightshade family. In our area, these are belladonna, datura, henbane. Suppositories, drops, tablets, and tinctures are produced directly with the extract of the leaves and roots of these plants. Such drugs are not uncommon, many of them are sold without a prescription, are considered natural and harmless, and can be found in almost any home medicine cabinet. In fact, drugs with alkaloids are potent agents, require adherence to the dosage regimen and caution during storage.
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Causes atropine poisoning
Poisoning with this substance occurs accidentally when drugs containing it are dosed incorrectly, when the fruits of poisonous plants are consumed, or intentionally when it is used as a drug.
The main risk factors for intoxication are, first of all, carelessness or lack of basic knowledge. Thus, small children, left to their own devices, may try the fruits of a poisonous plant out of curiosity and a desire to try everything "by tooth", and they do not need much to be poisoned - 2-3 belladonna berries or 15-20 datura seeds.
Adults who have not studied the instructions for the drug properly, who self-medicate or who have ignored the doctor's warning about dosage, can poison themselves or, even worse, harm their child. You can even poison yourself with an overdose of eye drops, inhaling the vapors of a bouquet of wild flowers that contains datura, although of course, getting a toxic substance inside is more dangerous.
The cause of poisoning may be the desire to get a drug high.
The pathogenesis of intoxication is based on the ability of atropine to bind mainly to muscarinic cholinergic receptors, in addition, although to a much lesser extent, atropine can also bind to nicotinic cholinergic receptors, making them insensitive to the neurotransmitter acetylcholine. This leads to an increase in its concentration in the synapse, as a result of which the transmission of nerve impulses in different parts of the brain slows down. Violation of acetylcholine metabolism causes a disorder of higher nervous activity, as well as parasympathetic (cholinergic) innervation.
Certain doses of atropine and its precursor (the maximum daily dose prescribed for adults is no more than 2 mg orally, for children - 0.1-1 mg) by acting mainly on the cerebral cortex cause an acute psychotic reaction, accompanied by motor excitation. The well-known old expression "ate too much henbane" is not without foundation - a person under the influence of this hallucinogen becomes inadequate.
If no help is provided, prolonged overexcitation of the cholinergic systems leads to their exhaustion, suppression of reflexes - respiratory paralysis, amnesia, loss of consciousness. Coma and death are possible.
Atropine-like alkaloids are absorbed fairly quickly when they come into contact with the mucous membranes of the eyes and digestive tract. The rate depends on the dose and how full the stomach is of food. If atropine alkaloids are taken on an empty stomach, the first symptoms of intoxication are observed after a few minutes, and the full picture of poisoning develops in an hour or two. Injectable forms act even more intensely. Toxic substances are broken down by the liver and excreted in urine and sweat. The body is freed from half of the dose taken within 24 hours, but you still have to survive these 24 hours.
Statistics show that poisoning with muscarinic receptor blockers accounts for approximately 12-15% of all chemical intoxications. Most victims are children who ate a poisonous plant or tried atropine-containing medications stored in an accessible place.
Symptoms atropine poisoning
The first signs of atropine in the body are externally manifested by dilated pupils, which stop responding to changes in illumination. This is accompanied by an increase in intraocular pressure, the appearance of a veil before the eyes, and after an hour or two, paralysis of accommodation and photophobia may occur.
At the same time, discomfort occurs on the mucous membranes of the mouth and nasopharynx. There is a noticeable dryness up to a burning sensation, strong thirst, which is associated with a decrease in the production of saliva, bronchial secretions. The patient finds it difficult to swallow, the voice becomes hoarse or disappears completely.
His arms and legs begin to tremble, and painful muscle spasms may occur.
The secretion of gastric and pancreatic juices decreases. Frequent painful false urges to empty the bowels (tenesmus) may appear.
Poisoning with alkaloids of the atropine group is manifested by reddening and dryness of the skin, scarlet fever-like rash (more often in children). The patient's pulse quickens (it can reach 160-190 beats/min). In small children, due to the low tone of the vagus nerve, tachycardia may not occur.
Severe intoxications are accompanied by hyperthermia with pyretic values, caused by impaired sweating. The patient has logorrhea, motor agitation, impaired coordination, headache, dyspnea, hallucinations and secondary delirium up to a violent state and complete loss of orientation. There may be convulsions, epileptiform seizures. The patient behaves inappropriately, there are signs of psychosis.
The excited state lasts for several hours. It may be replaced by depression of the central nervous system. In this case, mobility is limited and the muscles relax. The patient may lose consciousness. Dyspnea periodically gives way to shallow and rare respiratory movements, which accelerate and become frequent and deep, then slow down again (Cheyne-Stokes breathing), the face becomes pale with a bluish tint. The patient's pulse is rapid, weak, and irregular. A decrease in blood pressure is observed.
Acute atropine poisoning can be fatal. The patient dies from suffocation due to paralysis of the respiratory center, however, most cases of acute intoxication end in recovery. This takes two to four days, mydriasis sometimes lasts up to two weeks.
The phases of atropine poisoning: excitation and depression, can be expressed to varying degrees depending on the dose taken, body weight, age of the patient and individual reaction.
Mild poisoning is manifested by mydriasis, cycloplegia, dryness and hyperemia of the mucous membranes and skin, rapid heartbeat, weakened intestinal peristalsis, urinary retention, anxiety and speech impairment, trembling in the limbs. Gradually, this condition turns into sleep.
In medicine, when treating certain diseases accompanied by severe muscle weakness, drugs are used that enhance the action of acetylcholine by inhibiting the activity of the enzyme that catalyzes the reaction of its breakdown - cholinesterase. They have a reversible and irreversible effect on the enzyme. In the first case, when their action ceases, the enzymatic activity is restored, in the second - it is not. Medicines cause intoxication in case of overdose.
Irreversible anticholinesterase effects are caused by organophosphorus fertilizers and insecticides when they enter the human body. These substances can cause severe poisoning even when they come into contact with the skin, since they are well absorbed.
Poisoning with irreversible anticholinesterase agents manifests itself in effects directly opposite to atropine - hypersalivation, hyperhidrosis, pupillary constriction, accommodation spasm. Peristalsis of the gastrointestinal tract increases, resulting in abdominal pain, vomiting, frequent urge to defecate. Abnormally active contraction of the bronchial muscles leads to difficult wheezing, dyspnea due to spasms. Slowing of the pulse, muscle tremor are observed.
Neurological symptoms, however, are similar to atropine poisoning: psychomotor agitation turns into depression of reflexes.
Severe poisoning results in convulsions, hypotension and collapse. The cause of death is respiratory paralysis.
Anticholinesterase agents and muscarinic cholinergic receptor blockers produce opposite effects - they excite or inhibit parasympathetic innervation, and therefore are antidotes for corresponding acute poisonings.
Chronic atropine poisoning occurs with prolonged use and small overdoses. The following are observed: dilated pupils, accommodation disorders, dry mucous membranes and skin, dizziness, slightly increased pulse, tremors in the extremities, delayed emptying of the bladder and constipation.
Complications and consequences
The worst outcome of atropine poisoning is death from respiratory paralysis. However, the consolation is that this happens extremely rarely. Mostly, the person is helped in time, and he survives.
However, severe poisoning and prolonged coma may be complicated by the development of severe memory impairment and mental retardation, toxic polyneuritis or inflammation of the meninges. The substance, which has entered the body in a toxic dose, affects the muscle layer and tissues of all organs, disrupts the functioning of the glands. Complications of poisoning may include pneumonia, pulmonary atelectasis, digestive pathologies, glaucoma, retinal detachment.
Diagnostics atropine poisoning
Atropine poisoning is diagnosed based on clinical symptoms and information about its use. There are no tests or instrumental diagnostics that can confirm or refute atropine intoxication. The only test is to drop a drop of the patient's urine into the eye of a rabbit or cat. Their pupils should dilate, which confirms the presence of atropine in the body.
Differential diagnosis
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Treatment atropine poisoning
First aid for poisoning with atropine or poisonous plants (ingested through the mouth) is gastric lavage. The patient is given 2-3 liters of warm water with crushed tablets of activated carbon or the same amount of a weak pink solution of potassium permanganate to drink. An ambulance is called at the same time. The unconscious patient is turned on his side to avoid suffocation when the tongue sinks.
The patient is hospitalized. Depending on the patient's condition, stabilization measures are taken. Gastric lavage may be performed through a tube, the tip of which must be lubricated with Vaseline oil so as not to damage the overdried esophagus.
If the patient's condition does not allow gastric lavage, a subcutaneous injection of apomorphine (emetic) is given to quickly remove the remaining toxic substance. In addition, a siphon enema with a tannin solution (0.5%) is prescribed.
In case of respiratory dysfunction, patients may be prescribed artificial ventilation or tracheal intubation.
To remove the absorbed poison, forced diuresis with alkalization of the blood and detoxifying hemosorption are performed.
The patient is required to be given an antidote for atropine poisoning - in this capacity, reversible anticholinesterase agents are used to eliminate the blockade of cholinergic receptors, which have the ability to have a directly opposite effect: to restore the tone of the muscles of the bronchi, gastrointestinal tract, musculoskeletal system, the functioning of the glands, and to reduce intraocular pressure.
For example, prozerin is administered subcutaneously or drip-drip in case of atropine poisoning, diluted in saline. The administration is repeated. First, 3 ml of a 0.05% solution of the drug is administered, then, if the effect is insufficient, the administration is repeated. Up to 12 ml of prozerin solution can be administered within 20-30 minutes. The drug mainly restores parasympathetic innervation, since it poorly overcomes the blood-brain barrier and its central effect is weak.
Physostigmine is used for atropine poisoning in patients with convulsions, pyretic temperature values and development of acute vascular insufficiency. It is used intravenously. Small children approximately 0.5 mg, in adolescence - 1 mg. Injections are given every 5-20 minutes until the signs of the anticholinergic effect of atropine disappear.
Antidote drugs are used with caution, ensuring that a satisfactory balance between their effects is achieved. The dose is selected empirically, and subsequent doses of the drug are unpredictable. They are usually lower than the initial dose, since some of the drug is excreted from the body. Physostigmine is not recommended for use at low temperatures, non-dangerous hallucinations or delirium.
Other medications are prescribed symptomatically. Psychomotor agitation is relieved by antipsychotics, convulsions by barbiturates, hyperthermia is treated with external cooling (ice packs, wet wraps) and antipyretic agents, and accelerated pulse is normalized with β-blockers. Treatment is aimed at restoring and maintaining vital functions of the body.
After discharge from the hospital, during the rehabilitation period, much attention should be paid to the patient's daily routine and nutrition. The diet should be dominated by nutritious foods containing minerals, proteins and vitamins. Greens, vegetables, fruits, lean meat and fish, fermented milk products will restore strength and energy, and will also have a beneficial effect on the functioning of the digestive organs.
Daily walks in the fresh air are recommended, the duration of which should be gradually increased; therapeutic exercise will be useful.
Acute atropine poisoning can have too serious consequences, so it is not recommended to use folk remedies. You need to call an ambulance and do not refuse hospitalization. Herbal treatment can be practiced during the recovery period - drink vitamin teas, brew infusions that strengthen the immune system.
Homeopathy also recommends, in case of poisoning, first of all, to remove the poison from the body, that is, to wash the stomach and induce vomiting, do an enema. There is no specific antidote in homeopathy, the treatment is symptomatic. Given the danger of this poisoning, homeopathy can be used only in its very mild forms or in the recovery period.
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Prevention
When treating with drugs containing atropine, it is necessary to strictly follow the doctor's recommendations and dosage. If the first symptoms of overdose appear (dry mucous membranes, thirst, lethargy, anxiety, drowsiness), it is necessary to inform the doctor.
Keep medicines containing atropine out of the reach of children.
Do not leave small children unattended, study the appearance of poisonous plants yourself and tell older children about them. In general, teach them not to eat unfamiliar berries, not to collect bouquets of wild unknown plants and explain why this should not be done.