Adenosine

Intravenous adenosine injection is indicated for the following. Conversion to sinus rhythm of paroxysmal supraventricular tachycardia (PSVT), including that associated with accessory bypass tracts (Wolff-Parkinson-White Syndrome). When clinically advisable, appropriate vagal maneuvers (e.g., Valsalva maneuver), should be attempted prior to adenosine injection administration. It is important to be sure the adenosine injection solution actually reaches the systemic circulation. Adenosine Injection does not convert atrial flutter, atrial fibrillation, or ventricular tachycardia to normal sinus rhythm. In the presence of atrial flutter or atrial fibrillation, a transient modest slowing of ventricular response may occur immediately following adenosine injection administration.

Adenosine Injection slows conduction time through the A-V node, can interrupt the reentry pathways through the A-V node, and can restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia (PSVT), including PSVT associated with Wolff-Parkinson-White Syndrome. Adenosine Injection is antagonized competitively by methylxanthines such as caffeine and theophylline, and potentiated by blockers of nucleoside transport such as dipyridamole. Adenosine Injection is not blocked by atropine.

For rapid bolus intravenous use only. Adenosine Injection, USP should be given as a rapid bolus by the peripheral intravenous route. To be certain the solution reaches the systemic circulation, it should be administered either directly into a vein or, if given into an IV line, it should be given as close to the patient as possible and followed by a rapid saline flush. Adult Patients The dose recommendation is based on clinical studies with peripheral venous bolus dosing. Central venous (CVP or other) administration of adenosine injection has not been systematically studied. The recommended intravenous doses for adults are as follows: Initial dose: 6 mg given as a rapid intravenous bolus (administered over a 1 to 2 second period).

Intravenous adenosine injection is contraindicated in: Second- or third-degree A-V 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). Known hypersensitivity to adenosine.

Heart Block Adenosine Injection exerts its effect by decreasing conduction through the A-V node and may produce a short lasting first-, second- or third-degree heart block. Appropriate therapy should be instituted as needed. Patients who develop high-level block on one dose of adenosine injection should not be given additional doses. Because of the very short half-life of adenosine, these effects are generally self-limiting. Appropriate resuscitative measures should be available. Transient or prolonged episodes of asystole have been reported with fatal outcomes in some cases. Rarely, ventricular fibrillation has been reported following adenosine injection administration, including both resuscitated and fatal events. In most instances, these cases were associated with the concomitant use of digoxin and, less frequently with digoxin and verapamil.

The following reactions were reported with intravenous adenosine injection used in controlled U.S. clinical trials. The placebo group had a less than 1% rate of all of these reactions. Cardiovascular Facial flushing (18%), headache (2%), sweating, palpitations, chest pain, hypotension (less than 1%). Respiratory Shortness of breath/dyspnea (12%), chest pressure (7%), hyperventilation, head pressure (less than 1%). Central Nervous System Lightheadedness (2%), dizziness, tingling in arms, numbness (1%), apprehension, blurred vision, burning sensation, heaviness in arms, neck and back pain (less than 1%). Gastrointestinal Nausea (3%), metallic taste, tightness in throat, pressure in groin (less than 1%). Post Marketing Experience The following adverse events have been reported from marketing experience with adenosine injection.

Intravenous adenosine injection has been effectively administered in the presence of other cardioactive drugs, such as quinidine, beta-adrenergic blocking agents, calcium channel blocking agents, and angiotensin converting enzyme inhibitors, without any change in the adverse reaction profile. Digoxin and verapamil use may be rarely associated with ventricular fibrillation when combined with adenosine injection. Because of the potential for additive or synergistic depressant effects on the SA and AV nodes, however, adenosine injection should be used with caution in the presence of these agents. The use of adenosine injection in patients receiving digitalis may be rarely associated with ventricular fibrillation. The effects of adenosine are antagonized by methylxanthines such as caffeine and theophylline.

Store at 20° to 25°C (68° to 77°F). DO NOT REFRIGERATE as crystallization may occur. If crystallization has occurred, dissolve crystals by warming to room temperature.