Adenosine

Pronunciation

Pronunciation: ah-DEN-oh-seen
Class: Antiarrhythmic agent, In vivo diagnostic aid

Trade Names

Adenocard
- Injection 3 mg/mL

Adenoscan
- Injection 3 mg/mL

Pharmacology

Slows conduction through AV node; can interrupt reentry pathways through AV node and restore normal sinus rhythm.

As a diagnostic aid, adenosine activates purine receptors (cell-surface A 1 and A 2 adenosine receptors). There is evidence to support both inhibition of the slow inward calcium-current reducing calcium uptake and activation of adenylate cyclase through A 2 receptors in smooth muscle cells. Adenosine may also lessen vascular tone by modulating sympathetic neurotransmission.

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Pharmacokinetics

Distribution

Rapidly cleared from circulation via cellular uptake, primarily by erythrocytes and vascular endothelial cells.

Metabolism

Rapidly metabolized intracellularly to adenosine monophosphate or inosine. Inosine is ultimately degraded to uric acid.

Elimination

Extracellular adenosine has a half-life of less than 10 sec in whole blood.

Special Populations

Renal Function Impairment

Renal failure would not be expected to alter the effectiveness or tolerability of adenosine.

Hepatic Function Impairment

Hepatic failure would not be expected to alter the effectiveness or tolerability of adenosine.

Indications and Usage

Conversion to sinus rhythm of paroxysmal supraventricular tachycardia (PSVT), including that associated with Wolff-Parkinson-White syndrome; adjunct to thallium-201 myocardial perfusion scintigraphy in patients unable to exercise adequately.

Unlabeled Uses

Noninvasive assessment of patients with suspected coronary artery disease in conjunction with thallium tomography.

Contraindications

Second- or third-degree AV block (except in patients with functioning artificial pacemaker); sinus node disease, such as sick sinus syndrome or symptomatic bradycardia (except in patients with functioning artificial pacemaker); known hypersensitivity to adenosine; known or suspected bronchoconstrictive or bronchospastic lung disease (when use as a diagnostic aid).

Dosage and Administration

PSVT
Adults and Children 50 kg or more

IV 6 mg initially as rapid IV bolus. If first dose does not eliminate PSVT within 1 to 2 min, give 12 mg as rapid IV bolus; 12 mg dose may be repeated a second time if necessary. Doses over 12 mg are not recommended.

Children less than 50 kg

IV 0.05 to 0.1 mg/kg as rapid IV bolus given either centrally or peripherally. If conversion of PSVT does not occur within 1 to 2 min, additional bolus injections can be administered at incrementally higher doses, increasing the amount given by 0.05 to 0.1 mg/kg. Continue this process until sinus rhythm is established or a max single dose of 0.3 mg/kg (up to 12 mg) is used.

Diagnostic Aid
Adults

IV 140 mcg/kg/min infused for 6 min (total dose, 0.84 mg/kg). The required dose of thallium-201 should be injected directly into the adenosine infusion set at the midpoint of the adenosine infusion (ie, after the first 3 min of adenosine).

General Advice

  • For PSVT, administer either directly into vein or, if given into IV line, in most proximal IV line and follow with rapid saline solution flush.
  • For use as a diagnostic aid, administer as a continuous peripheral IV infusion as close to the venous access as possible.
  • Do not administer if solution is cloudy or sediment is present.

Storage/Stability

Store at 59° to 86°F. Do not refrigerate because crystallization may occur. If crystallization has occurred, dissolve crystals by warming to room temperature. Discard unused portion.

Drug Interactions

Carbamazepine

May produce higher degrees of heart block. Closely monitor cardiac function.

Cardio active drugs (eg, ACE inhibitors [eg, captopril], antiarrhythmic agents [eg, quinidine], beta-adrenergic blocking agents [eg, propranolol], calcium channel blocking agents [eg, verapamil], cardiac glycosides [eg, digoxin])

Use adenosine with caution in the presence of these agents because of potential additive or synergistic depressant effects on the SA and AV nodes. The use of adenosine with digoxin and verapamil may rarely be associated with ventricular fibrillation. Closely monitor cardiac function.

Dipyridamole

Potentiates effects of adenosine; smaller doses may be adequate.

Methylxanthines (eg, caffeine, theophylline)

Effects of adenosine may be antagonized; larger doses of adenosine may be needed.

Adverse Reactions

Cardiovascular

Flushing (44%); AT segment depression, first-degree AV block, second-degree AV block (3%); hypotension (2%); arrhythmia (1%); atrial fibrillation, bradycardia, prolonged asystole, torsades de pointes, transient increase in BP, ventricular fibrillation, ventricular tachycardia (postmarketing).

CNS

Headache (18%); light-headedness/dizziness (12%); nervousness, paresthesia (2%); numbness, tingling in arms (1%); loss of consciousness and seizure activity, including generalized tonic-clonic seizures (postmarketing).

GI

GI discomfort (13%); nausea (3%); vomiting (postmarketing).

Respiratory

Dyspnea/urge to breathe deeply (28%); bronchospasm, respiratory arrest (postmarketing).

Miscellaneous

Chest discomfort (40%); chest pressure (7%); throat, neck, or jaw discomfort, upper extremity discomfort (4%); injection-site reaction (postmarketing).

Precautions

Monitor

Monitor BP and cardiac rhythm during and after administration. Monitor for transient asystole.


Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy not established when used as a diagnostic aid. Adenosine for treatment of PSVT has been used in neonates, infants, children, and adolescents.

Elderly

Use with caution.

Arrhythmias

At time of conversion to normal sinus rhythm, new arrhythmias may appear on ECG; these are usually self-limiting.

BP

Hypertension and/or hypotension may occur. Use with caution in autonomic dysfunction, stenotic valvular heart disease, pericarditis or pericardial effusions, stenotic carotid artery disease with cerebrovascular insufficiency, or uncorrected hypovolemia because of the risk of hypotensive complications in these patients.

Cardiac effects

Fatal cardiac arrest, sustained ventricular tachycardia (requiring resuscitation), and nonfatal MI have been reported coincident with adenosine as a diagnostic aid. Patients with unstable angina may be at greater risk. Ensure that appropriate resuscitative measures are available.

Heart block

Drug may produce short-lasting heart block and/or sinus bradycardia. Use with caution in preexisting first-degree AV block or bundle branch block and avoid in high-grade AV block or sinus node dysfunction (except in patents with a functioning artificial pacemaker). Patients who develop high-level heart block (eg, third-degree) after 1 dose should not receive repeat doses.

Respiratory effects

May cause respiratory alkalosis. Adenosine inhalation has been reported to cause bronchoconstriction in asthmatic patients. Use with caution in patients with obstructive lung disease not associated with bronchoconstriction (eg, bronchitis, emphysema) and avoid use in patients with bronchoconstriction or bronchospasm (eg, asthma). Discontinue in any patient who develops severe respiratory difficulties.

Patient Information

  • Inform patient to report the following symptoms to health care provider: chest pressure, dizziness, facial flushing, headache, light-headedness, numbness or nausea, shortness of breath, tingling in arms.

Copyright © 2009 Wolters Kluwer Health.

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