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Adenosine is a medicine that contains naturally endogenous purine nucleoside that is found in the body’s cells and has anti-arrhythmic effects.
What is the composition and action of Adenosine?
Adenosine contains endogenous purine nucleoside that occurs naturally in the cells of the body and regulates the work of the heart. Adenosine opens the potassium channel and prevents the opening of a free calcium channel; is an indirect calcium antagonist. As a result, conduction in the atrioventricular node of the heart is slowed down and the function of the sinus node is inhibited. The drug regulates the work of the heart and prevents atrial fibrillation and flutter. However, it does not restore the sinus rhythm in the irregular work of the ventricles. Administration of Adenosine enables the assessment of the heart rate and frequency of supraventricular contractions during the ECG examination.
When is Adenosine used?
Adenosine is given to stop a tachyarrhythmia quickly, which is a too fast and irregular heartbeat at the same time. It is used to regulate the tachyarrhythmia of the AV node, i.e. nodal tachycardia and atrioventricular tachycardia. Adenosine is also given before an ECG test to better distinguish between supraventricular tachyarrhythmias and ventricular tachycardia. Adenosine is also used to treat acute intermittent porphyria.
Adenosine dosage
Adenosine is administered strictly according to the doctor’s instructions. The usual dose is 3 mg – if no effect after 1-2 minutes, another 6 mg dose is given, followed by a third 12 mg dose if still no effect. Adenosine is administered as an injection.
Contraindications to the use of Adenosine
Adenosine must not be administered to patients who are hypersensitive to its active ingredient, i.e. adenosine. Contraindication to the use of Adenosine is also second or third degree AV block (except for patients with implanted cardiac pacemakers), sinus node failure (except for patients with implanted cardiac pacemakers) and bronchial asthma. Particular caution should be exercised with the use of Adenosine in patients with COPD, atrial flutter or fibrillation with an additional conduction pathway and with low blood pressure (an excessive drop in blood pressure, i.e. hypotension may occur). Another contraindication to the use of Adenosine is severe heart failure. In the case of pregnancy and breastfeeding, Adenosine may be used only when absolutely necessary.
Possible side effects of Adenosine
Adenosine administered in excessive doses may cause bronchospasm and hypotension. Adenosine can cause facial flushing, bradycardia, asystole, atrioventricular block, extra atrial contractions, irregular heartbeat, ventricular excitability, shortness of breath, chest tightness, nausea, headache, dizziness, sweating, palpitations, metallic taste in the mouth, pain in the limbs and back pain. Adenosine cannot be overdosed as the increased dose of adenosine is immediately removed from the body.
Precautions when using the drug Adenosine
Particular caution should be exercised when administering Adenosine to patients who are concomitantly taking digoxin or dipyridamole. Be sure to tell your doctor about all medications you are taking at the time, as Adenosine may react with them. Adenosine also reacts with nicotine – it enhances the effect of adenosine.