Paracetamol overdose
Paracetamol is a substance from the group of anilides, which has an analgesic, antipyretic effect and a mild anti-inflammatory effect.
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Affordability combined with high efficacy and favorable safety profile allowed Paracetamol to be included in the list of essential drugs of the World Health Organization. In the Russian Federation, the drug is included in the list of vital.
The mechanism of action of paracetamol is associated with inhibition of cyclooxygenase-1 and -2 (COX1 and COX2, respectively), the key enzymes of the cycle of conversion of arachidonic acid to prostaglandins, which prevents the development of the inflammatory process and inhibits pain. In addition, paracetamol reduces the activity of the thermoregulatory center in the brain, thereby realizing the antipyretic effect.
The main indications for admission are:
- pain syndrome of mild or moderate intensity (headache, migraine, toothache, neuralgia, myalgia, algomenorrhea; pain in case of injuries, burns);
- fever accompanying infectious and inflammatory diseases.
More than 100 over-the-counter drugs are known containing paracetamol as the main active substance: Panadol, Calpol, Tsefekon, Efferalgan and others. Paracetamol preparations are available in the form of tablets (including soluble ones), rectal suppositories, suspensions, and granules for preparing a suspension.
When taken orally, the drug is well absorbed from the gastrointestinal tract into the systemic circulation, the maximum plasma concentration is determined after 10-60 minutes. The therapeutic effect lasts an average of 6 hours.
Despite the fact that in a therapeutic dosage, Paracetamol has extremely low toxicity, in the case of deliberate or accidental use of extreme doses of the drug through negligence, severe consequences for the body may develop. First of all, the liver suffers, and the kidneys, gastrointestinal tract, heart, central nervous system are also involved in the pathological process.
In patients with chronic liver diseases, the development of acute intoxication is possible even when taking a therapeutic dose. For the same reason, it is forbidden to consume alcohol during paracetamol treatment.
How much paracetamol is needed for an overdose?
In adults and adolescents weighing more than 60 kg, paracetamol is administered orally or rectally in a single dose of 500 mg, the frequency of administration is up to 4 times a day. The maximum duration of treatment is 5-7 days.
The maximum single dose is 1 g, the daily dose is 4 g, the course dose is 28 g.
Single doses for children:
- up to 3 months is determined individually, depending on body weight, at the rate of 10 mg / kg;
- from 3 months to 1 year, the dose is 60–120 mg;
- from 1 to 5 years - 125-250 mg;
- 6-12 years old - 250-500 mg.
The frequency of admission is no more than 4 times a day with an interval of at least 4 hours. The maximum duration of treatment is 3 days.
Violation of the recommended dosage regimen entails an overdose of the drug with the development of acute intoxication and toxic damage to target organs.
Signs of a paracetamol overdose
In the development of acute intoxication with paracetamol, 4 consecutive stages are distinguished.
Stage I
Acute intoxication. It develops several hours later (usually 1.5–2 hours) after taking the drug and lasts up to a day. There are no specific manifestations at this stage. The victim makes general complaints:
- general malaise;
- weakness, decreased or lack of appetite;
- headache;
- nausea, vomiting.
Increased sweating, pallor of the skin are objectively determined.
Stage II
It is characterized by incipient toxic damage to the tissues of the hepatobiliary zone. It develops within 24-48 hours from the moment of overdose. This stage is characterized by regression of the symptoms that have arisen earlier or a significant decrease in their severity (a period of imaginary well-being).
The victims often complain of a feeling of heaviness and moderate pain in the right hypochondrium. There is also a decrease in the amount of urine discharge.
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III stage
It usually develops within 72 to 96 hours after taking a high dose of the drug and is characterized by a maximum increase in symptoms and laboratory parameters indicating toxic liver damage:
- icteric staining of the skin, sclera and mucous membranes;
- intense pain in the right hypochondrium;
- complete loss of appetite, indomitable vomiting;
- generalized edema;
- bleeding of various localization (nasal, gingival, gastrointestinal, etc.);
- tachycardia, heart rhythm disturbances are possible;
- a state of oppressed consciousness, the development of a coma is possible;
- hallucinations, delusions, disorientation (toxic encephalopathy);
- a progressive decrease in the amount of urine discharge, up to complete cessation.
A further increase in the activity indices of AST, ALT, bilirubin, prothrombin time is noted in the laboratory.
Stage IV
For 5 days to 2 weeks or more, the damaged tissues are restored and liver functions normalized or the victim died from irreversible changes.
In addition to acute, it is possible to develop a chronic overdose of paracetamol with prolonged use of doses of the drug that exceed therapeutic doses, but not large enough for acute intoxication.
Chronic overdose symptoms:
- decreased appetite;
- periodic episodes of nausea of varying intensity, vomiting is possible;
- unmotivated weakness, apathy, drowsiness;
- heaviness and discomfort in the right hypochondrium;
- pallor or yellowness of the skin and mucous membranes;
- sweating;
- the appearance of minor bleeding (microhematuria, subcutaneous hematomas, nasal, subconjunctival bleeding, etc.)
First aid for paracetamol overdose
- Rinse the stomach, for which to drink 1-1.5 liters of warm water or a slightly pink solution of potassium permanganate and provoke an emetic urge by pressing on the root of the tongue.
- Take enterosorbent (Enterosgel, Polysorb, Polyphepan according to the scheme or activated carbon at the rate of 1 tablet per 10 kg of body weight).
- Take a saline laxative (magnesium sulfate).
Antidote
A specific antidote to paracetamol is acetylcysteine, which serves as a donor of SH-groups. Most effective in the first 8 hours after poisoning.
When is medical attention required?
It is necessary to seek help in several cases:
- a child, a pregnant woman, an elderly patient was injured;
- vomiting has become indomitable;
- traces of blood are determined in the vomit;
- bleeding has developed (of any localization);
- intense tachycardia, heart rhythm disturbances are determined;
- developed toxic encephalopathy (hallucinations, delirium, disorientation);
- the victim is inaccessible or has limited access to contact, is in an unconscious state;
- there is a sharp decrease in urine output.
Depending on the severity of the condition, the victim receives outpatient treatment or is hospitalized in the toxicological or intensive care unit of the hospital, where symptomatic pharmacotherapy of overdose is carried out:
- detoxification infusion therapy to reduce the concentration of toxins (Ringer's solution, isotonic sodium chloride solution);
- with the development of bleeding - filling the deficit in the volume of circulating blood (Reopolyglyukin, Gemodez), oxygen and hemostatic therapy (Etamsilat, Ditsinon), in severe cases - surgical intervention;
- antioxidants - vitamins E, C;
- hepatoprotectors (Carsil, Essentiale)
Possible consequences
The consequences of both acute and chronic overdose of paracetamol can be:
- acute liver failure;
- acute renal failure;
- multiple organ failure;
- toxic encephalopathy;
- acute pancreatitis;
- myocarditis;
- toxic pulmonary edema;
- coma, death.
Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
