LEXISCAN
CONTRAINDICATIONS:
                              -Bronchospasm with ongoing wheezing (12% vs 6% for placebo in
stable                                             moderate severe asthma - 4% vs 4% for placebo in mild to
moderate asthma)
                              -AVB 2nd or 3rd degree
(without PM)
                              
-SSS (without PM)
                              
-SBP < 90 mmHg
                              -Recent use of Dipyridamole
or dipyridamole containing drigs (Aggrenox)
                              
-Methyl Xanthines (aminophylline, caffeine, theobromine) block the effect
                              of adenosine and should be held at least 12 hours
                              
-Hypersensitivity to Adenosine
                              -Unstable acute MI or ACS
                              -Profound Bradycardia (< 40 bpm)

REVERSAL
                               -Hypotension (SBP<80 mmHg)
                               -Symptomatic, persistent 2nd or 3rd AVB
                               -Wheezing
                               -Chest pain with >2 mm ST depressions
                               -Signs of poor perfusion (pallor, cyanosis, cold skin)
                               -Patient's request
                        
Mechanism of action A2A receptor agonist that is a coronary vasodilator
Regadenoson is a low affinity receptor to A2A (ki ~ 1.3 microM), with at least 10-fold lower affinity for the
A1 receptor (Ki >16.5 microM), and weak, if any affinity for the A2B and A3 adenosine receptors.
The maximal plasma concentration of regadenoson is achieved within 1-4 min after injection and parallels
the onset of pharmacodynamic response. The
half-life is 2-4 minutes for the initial phase, an
intermediate phase follows with a half-life on average of 30 minutes coinciding with loss of the
pharmacodynamic effect. The
last phase consists of a decline in plasma concentration with a half-life of
~2hours.


Side Effects
-Common: Shortness of Breath, Headache, Flushing
Most reactions start soon after dosing and resolve 15 min afterwards except for headache (30 min)
-Less Common: chest discomfort, angina pectoris or ST, dizziness, chest pain, nausea, abdominal
discomfort, dysgeusia, flushing, feeling hot.
-Arrhythmias: 26% (compared to 30% with adenosine), 1st degree AVB 3% (7% adenosine), 2nd
degree AVB
-Most will experience an
increase in HR (5%, 3% for adenosine, and decrease in systolic BP>35
mm Hg (7%, 8% for adenosine)-decrease in diastolic BP > 25 mmHg
, within 45 min.

Dosage 5 mL (0.4 mg) and should be give as a rapid (approximately 10 seconds) injection into a
peripheral vein into a 22 gauge or larger catheter or needle. Followed by a
5 mL saline Flush
immediately after the injection of Regadenoson.
The Radiotracer should be injected 10-20 seconds
after the saline flush.
AMINOPHYLLINE        50 to 250 mg by slow IV injection (30-60 seconds)
REGADENOSON
RADIOTRACER
5ml (0.4mg) - 10 secs
followed by NS flush
10-20"