Clonidine poisoning is an acute pathological condition that occurs when the drug is taken at a dose exceeding 0.3 mg (2 tablets) or consumed more than 2.4 mg throughout the day. The main manifestations include bradycardia, hypotension, depression of consciousness, vomiting, weakness, pupil constriction, pallor of the skin, hypothermia, coma. It is diagnosed on the basis of anamnesis, clinical picture and results of toxicological analysis of urine. Treatment methods: forced diuresis, stool stimulation, naloxone administration, symptomatic therapy aimed at relieving existing disorders.
T46.5 Other antihypertensive agents not classified elsewhere
Clonidine poisoning occurs mainly among elderly people who systematically receive this drug as a treatment for hypertension. In addition, symptoms may occur in young people who have been exposed to criminal poisoning. With the strengthening of state control over the spread of potent drugs, the number of such cases has sharply decreased. In European countries and the United States, situations related to the intake of toxic doses of medications occur relatively rarely.
The toxic effect of clonidine manifests itself when using the drug in an amount exceeding the maximum permissible. Most often this happens when elderly patients forget about the previous intake and take another pill or two. The drug may be drunk by mistake if it is stored outside the factory packaging. There are cases when the drug was taken by young children, since it was kept in a place accessible to them. Other reasons:
- Criminal incidents. Previously, strong antihypertensive drugs were used to bring a person into a helpless state, to immobilize. Such poisoning was the most difficult, since the criminals used high doses of the toxicant. Today, such cases are quite rare, neuroleptics are more often used for criminal purposes.
- Incorrect selection of the therapeutic scheme. It happens that the dosage is excessive for a particular patient. This leads to an excessive decrease in blood pressure with a hypotension clinic. Such poisoning is not severe, since the amount of the drug does not exceed the permissible values.
- Suicide. Antihypertensive drugs are often used for suicide. A person who wants to pass away takes a large number of pills, their number can be measured in tens, and sometimes hundreds. Drug intoxication resulting from a suicide attempt is classified as extremely severe.
- Self-medication. Clonidine is a potent drug that leads to a sharp decrease in blood pressure. Its use with minor hypertension, even if therapeutic dosages are observed, can cause dizziness, fainting, collapse caused by an excessive drop in blood pressure.
- Reception with other drugs and alcohol. The use of alcohol with clonidine contributes to the depression of consciousness. The effect of the drug is enhanced when taken together with vasodilators, diuretics, other hypertension treatments, H1-histamine receptor blockers (suprastin, diphenhydramine).
The drug is absorbed in the stomach and intestines, the effect begins 20-30 minutes after ingestion. At the same time, alpha2-adrenoreceptors of the vasomotor center are stimulated, peripheral vascular resistance decreases due to the weakening of sympathetic innervation of veins and arteries. There is a decrease in cerebral blood flow, intracardiac conduction changes, the coronary rhythm and the process of thermoregulation of the body are disrupted. After taking toxic doses, all these effects reach a critical value.
Poisoning with clonidine at the somatogenic stage is manifested by disorders caused by metabolic acidosis, hypoxia, vascular insufficiency. There is a high probability of ischemic damage to the brain and internal organs. The disorder of the receptor apparatus is determined, hemodynamic instability is possible, the formation of AV blockades of varying severity, thrombosis, renal failure, pneumonia and endotoxic shock.
Medicinal exotoxicoses are classified according to several parameters: by origin (criminal, accidental, suicidal, iatrogenic); by the stage of the course (toxicogenic, somatogenic); by the presence of complications (with the development of coma, clinical death, multiple organ failure). The most commonly used variant is the division of pathology by severity:
- Easy. It is characterized by minimal external manifestations, absence of signs of depression of consciousness. Hospitalization is not required. Recovery occurs within a few hours against the background of increased fluid intake, taking drugs that increase blood pressure. There is no threat to life.
- Medium heavy. Poisoning with clonidine leads to a marked decrease in blood pressure and the appearance of other characteristic signs. The level of consciousness corresponds to stupor or sopor, its complete suppression does not occur. Breathing is independent, hemodynamics is maintained at an acceptable level without the use of hypertensive medications. Transportation to a toxicological hospital is indicated.
- Heavy. Coma or sopor develops, there is a drop in blood pressure below acceptable values. HELL is often not defined. The victim is diagnosed with a pathological type of breathing, a weak reaction of the pupils to light, an increased level of blood glucose, a significant decrease in body temperature. Hospitalization in the intensive care unit is required.
The symptom complex that occurs in patients with clonidine intoxication is mainly based on damage to the cardiovascular system. At the initial stage, there are complaints of weakness, dizziness, general deterioration of well-being, nausea and vomiting. The skin and mucous membranes are pale, acrocyanosis is present. Coordination of movements is broken. Breathing is rapid, body temperature is reduced, pulse is rare. Upon examination, narrowing of the icons, a decrease in muscle tone, drowsiness are revealed.
With moderate and severe poisoning, the symptoms are more pronounced. There is an oppression of consciousness. The patient reacts weakly to external influences, answers questions with a delay and in monosyllables, has difficulty solving the simplest mathematical examples. The pressure is sharply reduced or not determined, clonic-tonic seizures may occur. With the development of coma, breathing is shallow, weakened, rare. The skin is a marble shade, cold to the touch. Sometimes fibrillar twitching of skeletal muscles develops. Pupils are narrowed.
An early complication is the development of total atrioventricular blockade with dissociation of the atria and ventricles. It occurs in 1-2% of cases, mainly with severe lesions. It poses a direct threat to the patient’s life, requires the installation of a pacemaker. A more common phenomenon occurring in 15-20% of patients is vascular collapse. In 80% of cases, pathology can be stopped by infusion of cardiotonic drugs and a large number of infusion solutions.
At the somatogenic stage, acute renal failure is a danger. The frequency of occurrence is 1 case per 90-100 people. It is possible to eliminate the pathology with the timely initiation of appropriate therapy. Prolonged unconsciousness or on a ventilator can provoke congestive pneumonia. The disease is diagnosed in 40% of patients who have spent more than 7-10 days in the ICU. For the purpose of prevention, patients receive antibacterial treatment with broad-spectrum drugs.
The preliminary diagnosis is made by the doctor of the ambulance team. A clinical conclusion is made by a toxicologist or resuscitator who manages the patient. Consultations of narrow specialists may be required: cardiologist, gastroenterologist, psychiatrist. Poisoning should be differentiated from an overdose of other antihypertensive drugs, acute cardiovascular pathology, poisoning with narcotic substances. Diagnostic measures include:
- Physical examination. Blood pressure is 70/40 and lower, the pulse for mild intoxications is above 90 beats /minute, for severe ones — below 60 beats/ min. Clinical signs of drug-induced exotoxicosis are determined. The blood sugar level exceeds 5.5-6 mmol / l even in situations when the patient did not eat anything before poisoning. Body temperature 35.9-36.1° C.
- Hardware inspection. In severe cases, round-the-clock monitoring of blood pressure and pulse is indicated with the help of an anesthesiological monitor for 2 days. An ECG is required. The lengthening of the PQ interval is determined on the film, sometimes the layering of the P wave on the previous QRS complex, the loss of some ventricular complexes, the rise characteristic of early repolarization at the site of the transition of the QRS to the ST segment.
- Laboratory examination. The main method of confirming the diagnosis is the qualitative and quantitative determination of clonidine in blood and urine. In the presence of obvious symptoms, it is permissible to perform only a qualitative analysis. In a biochemical test, an increase in the activity of liver enzymes is detected, when studying the CSF and electrolyte composition, a pH shift below the 7.35 limit is detected.
Treatment consists of several stages. In addition to pharmacological and hardware support, people who have attempted suicide need to consult a psychiatrist. Therapeutic measures include resuscitation, general rehabilitation course, rehabilitation, psychotherapy (for patients with suicidal tendencies).
With depression of consciousness and respiration at the prehospital stage, naloxone is administered. Gastric lavage is indicated. While maintaining swallowing, the procedure is carried out in a non-probe way. Comatose states and sopor require the use of a thick probe. The criterion for the successful removal of gastric contents is considered to be clean rinsing water. After that, a suspension of activated carbon is injected into the stomach at the rate of 1 tablet per 10 kg of weight. Poisoning with clonidine requires infusion therapy with plasma substitutes, crystalloids, antitoxic solutions.
It is indicated for patients with severe forms of poisoning. It is carried out in an ICU. The patient is intubated, transferred to artificial lung ventilation. If prolonged respiratory support is planned, a tracheostomy is recommended. The main vital parameters are monitored around the clock, daily indicators of electrolytes, hydrogen number and blood gases, biochemical proportions are monitored. With psychomotor agitation, the patient is immersed in a drug-induced sleep, peripheral muscle relaxants are used in order to synchronize with the respiratory apparatus.
Since clonidine is excreted mainly in urine and feces, the patient is prescribed forced diuresis with the introduction of up to 10 liters of saline infusion solutions per day. The dose of loop diuretics in this case reaches 100-150 mg. A certain effect can be achieved with the help of intestinal lavage, the procedure is carried out for 4-5 hours. After that, it is necessary to introduce probiotics and synbiotics. Symptomatic and metabolic therapy is used: cardiotonics, analgesics, vitamins, antioxidants, circulatory agents, nootropics, benzodiazepines.
It is prescribed to patients with moderate poisoning who are in the toxicology department. Detoxification is carried out by forced diuresis. The volume of infusion and the dose of diuretics is significantly less than during treatment in intensive care. During the day, the patient receives 400-800 ml of crystalloid solutions. The rest of the liquid is injected enterally, pure drinking water, mineral water, fruit drinks, juices, and a decoction of rosehip are used. Laxatives are prescribed.
Monitoring of blood pressure and pulse is carried out by the average medical staff at least 2-3 times a day. In the presence of hypotension, caffeine and cordiamine are administered. Bradycardia is eliminated by subcutaneous infusion of atropine. A sharp deterioration of the condition is a reason for transferring the patient to the ICU. The patient is shown special control. First of all, this applies to people who have suffered a suicide attempt. If the victim continues to express suicidal thoughts, an individual post is organized around him.
The volume of rehabilitation measures is determined taking into account the causes of pathology and the existing somatic and mental disorders. Patients who have tried to commit suicide need to be treated by a psychotherapist or psychiatrist. Often this requires hospitalization of the patient in the appropriate medical facility. If poisoning with clonidine has led to the development of encephalopathy, the patient is placed in a neuropsychiatric boarding school or provided with constant monitoring at home.
Prognosis and prevention
Mild to moderate clonidine poisoning has a favorable prognosis. With the early start of antitoxic therapy, 95% of the victims can be saved. With severe lesions, the mortality rate reaches 30%. Patients who develop non-canceling cardiovascular collapse, total blockages of atrioventricular conduction, and multiple organ failure die. Such complications are usually found in people with long-term exposure to the toxicant, when most of the tablets have managed to be absorbed into the blood.
Prevention of clonidine poisoning consists in the exact selection of the dose of the drug. When prescribing antihypertensive drugs, the doctor should take into account the age, the state of the patient’s excretory systems, the interaction of clonidine with other medications. At home, the drug should be kept in the factory container. Cabinets with key-lockable doors are used for storage. For old people, tablets are laid out in special pillboxes, which exclude repeated use of the drug. People who are suicidal and have mental illnesses should not have access to a first aid kit.