adenosine

Adenosine is a medication belonging to class V antidysrhythmics, used to treat a type of irregular heart rhythm disorder known as paroxysmal supraventricular tachycardia (PSVT). PSVT is a condition in which intermittent episodes of rapid heart rate occur starting from the region above the ventricles. Adenosine is also used for diagnostic purposes in myocardial perfusion scintigraphy, a test that determines how well blood flows through the heart muscles.

Specialized cells in the right atrium known as the sinoatrial (SA) node, the heart’s natural pacemaker, generates electrical impulses at a regular rhythm to make the atria and ventricles contract in coordination to pump blood. The impulses make the atria contract first and the atrioventricular (AV) node delays the signal till the atria are empty. The impulses then travel through nerve fibers to the ventricles and make them contract.

PSVT is caused by abnormal functioning of the cardiac electrical circuit. Adenosine restores normal rhythm in PSVT by acting on the adenosine receptors in the atrioventricular node, slowing down the impulse conduction time and interrupting abnormal re-entry pathways of electrical impulses in the AV node.

Adenosine also binds to adenosine A2 receptors in the coronary arteries, dilating them and increasing the blood flow. Adenosine significantly increases blood flow in normal coronary arteries, but little or no increase in arteries that are narrowed due to plaque. Adenosine is used with the radioactive agent thallium-201 to identify narrowed coronary blood vessels and the risk for heart disease.

• Do not use adenosine in patients with heart rhythm disorders including:
  • Second or third-degree AV block (except in patients with a functioning artificial pacemaker)
  • Sinus node disease, such as sick sinus syndrome or symptomatic bradycardia (except in patients with a functioning artificial pacemaker)
• Do not use adenosine in patients with:
  • Known or suspected bronchoconstrictive or bronchospastic lung disease such as asthma
  • Known hypersensitivity to adenosine
• Use adenosine with caution in patients with first-degree AV block
• Cardiac arrest (fatal and nonfatal), heart attack (myocardial infarction), cerebrovascular accident (hemorrhagic and ischemic), and sustained ventricular tachycardia (requiring resuscitation) have occurred following adenosine use; avoid use in patients with unstable angina, acute myocardial ischemia, or cardiovascular instability, conditions in which the heart doesn’t get enough blood flow and oxygen
• Adenosine use in PSVT patients has caused atrial flutter/fibrillation; use with caution, particularly in Wolff-Parkinson-White syndrome, a condition with an extra electrical pathway in the heart
• Adenosine can cause hypertension or hypotension; use with caution in patients at risk
• At the time of conversion to normal sinus rhythm, abnormal rhythms may occur for a short period
• New-onset or recurrence of convulsive seizures have been reported following administration of adenosine; some seizures are prolonged and require emergency anticonvulsive management; aminophylline may increase risk of seizures associated with adenosine and methylxanthines use is not recommended

Common side effects of adenosine include:

• Flushing
• Chest pressure and discomfort
• Shortness of breath (dyspnea)
• Headache
• Throat, neck and jaw discomfort
• Gastrointestinal discomfort
• Lightheadedness
• Dizziness
• Upper extremity discomfort
• Electrical disturbances in the heart
• Abnormal ECG readings
• Low blood pressure (hypotension)
• Numbness and tingling (paresthesia)
• Irregular heart rhythms (arrhythmia)
• Nausea

Less common side effects of adenosine include:

• Chest pain
• Palpitations
• Ventricular arrhythmia
• Heart attack (myocardial infarction)
• Low heart rate (bradycardia)
• High blood pressure (hypertension)
• Sweating
• Rapid breathing (hyperventilation)
• Head pressure
• Cough
• Drowsiness
• Apprehension
• Emotional instability
• Tremors
• Back discomfort
• Lower extremity discomfort
• Weakness
• Heaviness in arms
• Neck and back pain
• Burning sensation
• Blurred vision
• Metallic taste
• Dry mouth
• Tongue discomfort
• Tightness in throat
• Ear discomfort
• Nasal congestion
• Pressure in the groin
• Urinary urgency

Rare side effects of adenosine include:

• Injection site reaction
• Nausea and vomiting
• Bronchospasm
• Respiratory arrest
• Prolonged flatline (asystole)
• Rapid ventricular contractions (ventricular tachycardia)
• Irregular ventricular rhythm (ventricular fibrillation)
• Abnormal ventricular rhythm (torsades de pointes)
• Slow heart rate (bradycardia)
• Atrial fibrillation
• Transient increase in blood pressure
• Seizures
• Loss of consciousness

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug.

Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

Injectable solution

• 3 mg/ml

Adult:

Paroxysmal Supraventricular Tachycardia

• Indicated for conversion to sinus rhythm of paroxysmal supraventricular tachycardia (PSVT), including that associated with accessory bypass tracts (Wolff-Parkinson-White Syndrome)
• Adenocard: 6 mg intravenous push over 1-3 seconds (maybe given as an intraosseous infusion) followed by a rapid flush with 20 ml normal saline, if no conversion within 1-2 minutes give 12 mg intravenous push, repeat a second time if necessary (30 mg total)

Dosing considerations

• When clinically advisable for paroxysmal supraventricular tachycardia (PSVT), appropriate vagal maneuvers (Valsalva maneuver), should be attempted before adenosine administration

Stress Testing (Diagnostic)

Indicated as an adjunct to thallium-201 myocardial perfusion scintigraphy in patients unable to exercise adequately

Adenoscan: 140 mcg/kg/minute intravenous infusion for 6 minutes

Other Indications and Uses

• Off label: sustained ventricular tachycardia (SVT)

Pediatric:

Paroxysmal Supraventricular Tachycardia

• Under 50 kg: 0.05 to 0.1 mg/kg rapid intravenous push over 1-3 seconds or intraosseous infusion, no more than 0.2 mg/kg/dose, followed by rapid flush with up to 5 ml 0.9% sodium chloride
• If necessary may give a second dose of 0.2 mg/kg intravenous push/intraosseous infusion, not to exceed the cumulative dose of 12 mg

Geriatric:

The elderly may experience more adverse effects from adenosine; they may be more sensitive

PSVT (Adenocard)

• 6 mg intravenously (IV) over 1-3 seconds (maybe given by intraosseous infusion [IO]) followed by a rapid flush with 20 ml normal saline (NS), if no conversion within 1-2 minutes give 12 mg IV, repeat a second time if necessary (30 mg total)

Adenoscan (Diagnostic)

• Stress testing (Adenoscan): 140 mcg/kg/minute intravenous infusion for 6 minutes

• Adenosine has a half-life of less than 10 seconds, toxic effects of adenosine usually resolve quickly once the drug is discontinued, although there have been reports of severe effects involving flatline (asystole), development of heart block, and cardiac ischemia.
• Theophylline has been used to treat persistent symptoms, in addition to appropriate supportive care.

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Adenosine has no known severe interactions with other drugs.
• Adenosine has no known serious interactions with other drugs.
• Moderate interactions of adenosine include:
  • dipyridamole
  • green tea
  • hawthorn
  • nicotine inhaled
  • nicotine intranasal
  • sevelamer
  • theophylline
• Mild interactions of adenosine include:
  • acebutolol
  • atenolol
  • bisoprolol
  • caffeine
  • carvedilol
  • celiprolol
  • esmolol
  • labetalol
  • lily of the valley
  • metoprolol

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information.

Check with your doctor or health care provider if you have any questions about the medication.

• Neither animal reproduction studies nor studies on pregnant women have been conducted with adenosine. It is not known if adenosine can cause fetal harm, use in pregnant women only if clearly needed.
• It is not known if adenosine is present in breast milk; decision should be made to interrupt nursing or not administer adenosine, taking into account the importance of treatment to the mother because of the potential for serious adverse reactions in nursing infants.