Nitroglycerin overdose
Nitroglycerin is used both on demand, as an emergency aid for ischemic heart disease, and as a component of routine pharmacotherapy for a number of cardiological and gastroenterological pathologies.
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Nitroglycerin - organic nitrate, is a colorless oily liquid, poorly soluble in water. It is used on an outpatient basis, usually in the form of sublingual tablets, sprays, aerosols and drops. Less commonly, transdermal drug delivery (through the skin) is used with the help of special patches or films. In a hospital setting, Nitroglycerin is used more often in the form of a concentrate for the preparation of an injection solution for parenteral administration.
The most effective is intravenous administration of the drug (in this case, the effect occurs within a few seconds) and taking pills under the tongue (the effect is realized within one and a half minutes and lasts up to half an hour).
Nitroglycerin has a whole range of beneficial effects:
- reduces stress on the heart;
- expands the blood vessels that feed the heart, thereby improving its blood supply;
- lowers blood pressure (BP);
- reduces pressure in the pulmonary capillaries;
- redistributes blood flow in favor of areas of the myocardium with signs of ischemia (weakened blood supply);
- suppresses hyperactivation of the sympathetic link of the nervous system;
- increases resistance to physical activity in patients with coronary heart disease;
- reduces the frequency and severity of angina attacks;
- relaxes the smooth muscles of the bronchi, biliary tract, esophagus, stomach, intestines, urinary system.
The main indications for the use of Nitroglycerin:
- angina pectoris (including spontaneous Prinzmetal);
- prevention of spasm of the coronary arteries with coronary angiography;
- acute myocardial infarction;
- acute and chronic heart failure;
- controlled arterial hypotension during surgical interventions and diagnostic procedures;
- dyskinesia of the esophagus and intestines;
- functional diseases of the gallbladder and ducts;
- gallstone disease in the exacerbation phase;
- acute pancreatitis.
A characteristic feature of Nitroglycerin is its ability to rapidly reduce blood pressure. Most often this happens immediately after taking the drug against the background of a change in posture - from a prone position to a sitting position. In this case, the so-called orthostatic collapse develops, manifested by a rapid fall in blood pressure, often with loss of consciousness.
How much nitroglycerin is needed for an overdose?
The standard dose of Nitroglycerin is 0.5–1.5 mg per dose. The treatment regimen for acute coronary syndrome recommends taking 3 tablets for a maximum of 15 minutes (if there is no effect after the first tablet, the next dose of the drug can be taken every 5 minutes). Taking more than 3 Nitroglycerin tablets at a time is prohibited.
The first signs of an overdose with Nitroglycerin appear when taking 4 or more tablets of the drug in a limited period of time. Symptoms of severe overdose develop when taking the drug at a dose of more than 20 mg / kg. At a concentration of 100-150 mg / kg nitroglycerin, death occurs.
When the drug is administered intravenously in a hospital setting, the development of an overdose is extremely rare, since the infusion rate and the dose of the substance are carefully calculated.
Signs of overdose
An overdose of Nitroglycerin is manifested by a number of characteristic symptoms:
- a pronounced decrease in blood pressure (systolic below 90 mm Hg. Art.);
- orthostatic reactions;
- reflex tachycardia;
- intense headache;
- dizziness;
- increased drowsiness, asthenia;
- anxiety, disorientation, lethargy, various psychotic reactions;
- feeling of heat, hot flashes;
- heartburn, nausea, vomiting, diarrhea;
- collapse;
- bluish staining of the skin;
- shortness of breath, chest tightness, need for deep breaths, shallow unproductive breathing.
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First aid for an overdose of Nitroglycerin
- Stop taking the drug immediately; if an intravenous infusion was made, turn off the system immediately.
- Give the victim a position with an elevated leg end.
- Gastric lavage, the use of enterosorbents and saline laxatives are impractical, including in the case of taking Nitroglycerin under the tongue, since the drug is absorbed directly into the systemic circulation, bypassing the gastrointestinal tract.
Antidote
There is no specific antidote to Nitroglycerin.
When is medical attention required?
Medical assistance is needed if:
- the victim is unconscious;
- a child or a pregnant woman is injured;
- BP is recorded below 80/50 mm Hg. Art.;
- the victim complains of palpitations, objectively there is a sharp tachycardia;
- developed neurological symptoms (loss of orientation in time and place, lethargy or excessive excitement, etc.);
- a sharp cyanosis of the skin and mucous membranes is determined;
- there is intense shortness of breath, change in breathing;
- there are traces of blood in the vomit or stool.
An ambulance team admits the victim to the cardiology or intensive care unit, where specific therapy is carried out:
- replenishment of circulating blood volume (Ringer's solution, isotonic sodium chloride solution, Polyglyukin, Reopoliglucin);
- oxygen therapy;
- the introduction of vasoconstrictor drugs - Norepinephrine, Dopamine;
- symptomatic therapy of developed disorders.
Possible consequences
The consequences of an overdose with Nitroglycerin can be:
- collapse, shock;
- stroke;
- progression of angina pectoris;
- acute myocardial infarction;
- renal and / or hepatic impairment;
- toxic pulmonary edema.
Prevention
To prevent a possible overdose with Nitroglycerin, you must not take more than 3 tablets of the drug in the event of an anginal attack. If there is no effect, you must immediately call the ambulance team.
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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!
