REGADENOSON Drug Interactions: What You Need to Know

INTERACTIONS No formal pharmacokinetic drug interaction studies have been conducted with Regadenoson injection.

• Methylxanthines, e.g., caffeine, aminophylline and theophylline, interfere with the activity of Regadenoson injection ( 7.1 , 12.2 ).
• Aminophylline may be used to attenuate severe and/or persistent adverse reactions to Regadenoson injection ( 7.1 , 10 ).
• Dipyridamole may increase the activity of Regadenoson injection. When possible, withhold dipyridamole for at least two days prior to Regadenoson injection administration ( 7.1 ).

7.1 Effects of Other Drugs on Regadenoson Injection

• Methylxanthines (e.g., caffeine, aminophylline and theophylline) are non-specific adenosine receptor antagonists that interfere with the vasodilation activity of Regadenoson injection [ see Clinical Pharmacology (12.2) and Patient Counseling Information (17) ]. Patients should avoid consumption of any products containing methylxanthines as well as any drugs containing theophylline or aminophylline for at least 12 hours before Regadenoson injection administration. Aminophylline may be used to attenuate severe or persistent adverse reactions to Regadenoson injection [ see Overdosage (10 ) ].
• In clinical studies, Regadenoson injection was administered to patients taking other cardioactive drugs (i.e., β-blockers, calcium channel blockers, ACE inhibitors, nitrates, cardiac glycosides, and angiotensin receptor blockers) without reported adverse reactions or apparent effects on efficacy.
• Dipyridamole may change the effects of Regadenoson injection. When possible, withhold dipyridamole for at least two days prior to Regadenoson injection administration.

7.2 Effect of Regadenoson injection on Other Drugs Regadenoson does not inhibit the metabolism of substrates for CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4 in human liver microsomes, indicating that it is unlikely to alter the pharmacokinetics of drugs metabolized by these cytochrome P450 enzymes.

Do not administer Regadenoson injection to patients with: · Second- or third- degree AV block, or · Sinus node dysfunction unless these patients have a functioning artificial pacemaker [ see Warnings and Precautions (5.2) ] . Do not administer Regadenoson injection to patients with: · Second- or third- degree AV block, or · sinus node dysfunction unless the patients have a functioning artificial pacemaker ( 4 ).

AND PRECAUTIONS

• Myocardial Ischemia. Fatal cardiac events have occurred. Avoid use in patients with symptoms or signs of acute myocardial ischemia, for example unstable angina or cardiovascular instability, who may be at greater risk. Cardiac resuscitation equipment and trained staff should be available before administration (5.1) .
• Sinoatrial (SA) and Atrioventricular (AV)

Nodal

Block. Adenosine receptor agonists, including regadenoson injection, can depress the SA and AV nodes and may cause first-, second- or third-degree AV block, or sinus bradycardia (5.2) .

• Atrial Fibrillation/Atrial Flutter. New-onset or recurrent atrial fibrillation with rapid ventricular response and atrial flutter have been reported (5.3) .
• Hypersensitivity, including anaphylaxis, angioedema, cardiac or respiratory arrest, respiratory distress, decreased oxygen saturation, hypotension, throat tightness, urticaria, and rashes have occurred. Have personnel and resuscitative equipment immediately available (5.4) .
• Hypotension. Adenosine receptor agonists, including regadenoson injection, induce vasodilation and hypotension. The risk of serious hypotension may be higher in patients with autonomic dysfunction, stenotic valvular heart disease, pericarditis or pericardial effusions, stenotic carotid artery disease with cerebrovascular insufficiency, or hypovolemia (5.5) .
• Hypertension. Adenosine receptor agonists, including regadenoson injection, may induce clinically significant increases in blood pressure particularly in patients with a history of hypertension and when the MPI includes low level exercise (5.6) .
• Bronchoconstriction. Adenosine receptor agonists, including regadenoson injection, may induce dyspnea, bronchoconstriction and respiratory compromise in patients with chronic obstructive pulmonary disease (COPD) or asthma. Resuscitative measures should be available (5.7) .
• Seizure. Regadenoson injection may lower the seizure threshold. New onset or recurrence of convulsive seizures has occurred. Some seizures are prolonged and require urgent anticonvulsive management. Methylxanthine use is not recommended in patients who experience a seizure in association with regadenoson injection (5.8) .
• Cerebrovascular Accident (Stroke). Hemorrhagic and ischemic cerebrovascular accidents have occurred (5.9) .

5.1 Myocardial Ischemia Fatal and nonfatal myocardial infarction (MI), ventricular arrhythmias, and cardiac arrest have occurred following regadenoson injection. Avoid use in patients with symptoms or signs of acute myocardial ischemia, for example unstable angina or cardiovascular instability; these patients may be at greater risk of serious cardiovascular reactions to regadenoson injection. Cardiac resuscitation equipment and trained staff should be available before administering regadenoson injection. Adhere to the recommended duration of injection [ see Dosage and Administration (2) ]. As noted in an animal study, longer injection times may increase the duration and magnitude of increase in coronary blood flow [ see Clinical Pharmacology (12.2) ]. If serious reactions to regadenoson injection occur, consider the use of aminophylline, an adenosine antagonist, to shorten the duration of increased coronary blood flow induced by regadenoson injection [ see Overdosage (10) ].

5.2 Sinoatrial and Atrioventricular Nodal Block Adenosine receptor agonists, including regadenoson injection, can depress the SA and AV nodes and may cause first-, second- or third-degree AV block, or sinus bradycardia requiring intervention. In clinical trials first-degree AV block (PR prolongation > 220 msec) developed in 3% of patients within 2 hours of regadenoson injection administration; transient second-degree AV block with one dropped beat was observed in one patient receiving regadenoson injection. In post-marketing experience, third-degree heart block and asystole within minutes of regadenoson injection administration have occurred [ see Adverse Reactions (6.2) ].

5.3 Atrial Fibrillation/Atrial Flutter New-onset or recurrent atrial fibrillation with rapid ventricular response and atrial flutter have been reported following regadenoson injection [ see Adverse Reactions (6.2) ].

5.4 Hypersensitivity, Including Anaphylaxis Anaphylaxis, angioedema, cardiac or respiratory arrest, respiratory distress, decreased oxygen saturation, hypotension, throat tightness, urticaria and rashes have occurred. In clinical trials, hypersensitivity reactions were reported in fewer than 1 percent of patients [ see Adverse Reactions (6.1) ]. Have personnel and resuscitative equipment immediately available.

5.5 Hypotension Adenosine receptor agonists, including regadenoson injection, induce arterial vasodilation and hypotension. In clinical trials, decreased systolic blood pressure (> 35 mm Hg) was observed in 7% of patients and decreased diastolic blood pressure (> 25 mm Hg) was observed in 4% of patients within 45 minutes of regadenoson injection administration. The risk of serious hypotension may be higher in patients with autonomic dysfunction, hypovolemia, left main coronary artery stenosis, stenotic valvular heart disease, pericarditis or pericardial effusions, or stenotic carotid artery disease with cerebrovascular insufficiency. In post-marketing experience, syncope, transient ischemic attacks and seizures have been observed [ see Adverse Reactions (6.2) ].

5.6 Hypertension Administration of adenosine receptor agonists, including regadenoson injection, may result in clinically significant increases in blood pressure in some patients. Among patients who experienced an increase in blood pressure in clinical trials, the increase was observed within minutes of regadenoson injection administration. Most increases resolved within 10 to 15 minutes, but in some cases, increases were observed at 45 minutes following administration [ see Clinical Pharmacology (12.2) ]. In post-marketing experience, cases of potentially clinically significant hypertension have been reported, particularly with underlying hypertension and when low-level exercise was included in the MPI [ see Adverse Reactions (6.2) ].

5.7 Bronchoconstriction Adenosine receptor agonists, including regadenoson injection, may cause dyspnea, bronchoconstriction, and respiratory compromise. Appropriate bronchodilator therapy and resuscitative measures should be available prior to and following regadenoson injection administration [ see Adverse Reactions (6.1) , Clinical Pharmacology (12.2) , Overdosage (10) and Patient Counseling Information (17) ].

5.8 Seizure Regadenoson injection may lower the seizure threshold; obtain a seizure history. New-onset or recurrence of convulsive seizures has occurred following regadenoson injection. Some seizures are prolonged and require emergent anticonvulsive management. Aminophylline may increase the risk of seizures associated with regadenoson injection. Methylxanthine use is not recommended in patients who experience a seizure in association with regadenoson injection administration.

5.9 Cerebrovascular Accident (Stroke) Hemorrhagic and ischemic cerebrovascular accidents have occurred. Hemodynamic effects of regadenoson injection including hypotension or hypertension may be associated with these adverse reactions [ see Warnings and Precautions (5.5) and (5.6) ].