| Adenosine: |
Naturally occuring Purine Nucleoside |
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Drug of choice ALL narrow complex PSVTs!!!
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IVP DOSING |
| 6mg |
rapid IVP followed by 20cc NS [preferably in a peripheral IV]. Hey, make it easy on yourself and use a stopcock, with the saline on one port and the Adenosine on the other!!! If it works the first time, great! If not, try, try again (and then stop)... |
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+ |
12mg for the second dose + 12mg for the third and final dose |
Adenosine is naturally formed as a breakdown product when ATP is converted to AMP (adenosine monophosphate). There is an official adenosine-receptor, and when stimulated, it causes the potassium channel to release potassium from cells within the AV node, causing a highly polarized state that effectively inhibits SVTs. During this proccess, the formation of cAMP is inhibited, preventing normal calcium channel operation. All this means that AV nodal conduction is slowed, and reentry pathways are depressed. This is why adenosine is the drug of choice for all narrow-complex PSVTs. Also, it is used in the diagnosis (but not treatment) of A Fib, A Flutter, and some ventricular arrythmias. In vascular smooth muscle cells, adenosine causes vasodilation, and it is used to both induce and maintain hypotension during surgery ("Like-Wow").
Side
Effects: Momentary onset of
a new dysrhythmia (just about any type), hypotension, flushing, dyspnea, chest
pain, SOB, diaphoresis, HA, metallic taste, nausea, visual changes, back/neck
pain, paresthesias (enough yet?), etc...
Contraindicated: VT, 2°
or 3°
AV block, SSS, action is blocked by theophylines, but is potentiated by
Dypyridamole (Persantine), and Carbamazepine (Tegratol).
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