adenosine
Brand: Adenocard
Prototype Drug
Drug Class: antiarrhythmic (Class V)
Drug Family: antiarrhythmic
Subclass: endogenous purine nucleoside
Organ Systems: cardiovascular
Mechanism of Action
Activates A1 receptors in AV node causing transient AV block; slows or terminates AV node-dependent reentry tachycardias; very short duration of action.
A1 adenosine receptors (AV node)
Indications
- PSVT termination (drug of choice)
- diagnosis of wide-complex tachycardias
Contraindications
- AF/flutter (does not convert but may cause severe bradycardia)
- WPW with pre-excitation
- 2nd/3rd degree AV block
- sinus node dysfunction
- asthma/COPD (relative — bronchospasm risk)
Adverse Effects
Common
- flushing
- chest tightness
- dyspnea
- transient AV block
- sense of impending doom
Serious
- transient asystole (brief)
- bronchospasm in reactive airway disease
- VF in WPW with rapid ventricular response
Pharmacokinetics (ADME)
| Absorption | IV only; rapid uptake by RBCs and endothelial cells |
| Distribution | very low |
| Metabolism | deamination in blood/tissues |
| Excretion | very rapid |
| Half-life | <10 seconds |
| Onset | immediate |
| Peak | immediate |
| Duration | 10-15 seconds |
| Protein Binding | <0% |
| Vd | 0.33 L/kg |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| methylxanthines (theophylline, caffeine) | competitive antagonists at A1 receptors — block adenosine effect; require higher dose | major |
| dipyridamole | blocks adenosine uptake — potentiates effect (use 1/4 dose) | major |
Nursing Considerations
- Rapid IV push (1-3 seconds) via large antecubital vein followed immediately by 20mL NS flush
- Warn patient about very brief side effects (flushing, chest tightness — seconds only)
- Theophylline and caffeine antagonize effect — may require higher doses
- Dipyridamole potentiates: start with 1 mg in dipyridamole-treated patients
- Record ECG during administration — diagnostic tool
Clinical Pearls
- Half-life <10 seconds: adverse effects self-limited, resolving in seconds
- Theophylline antagonism: competitive A1 blocker — may need higher dose or alternative agent
- Not effective in non-AV-node-dependent arrhythmias (VT, AF, flutter)
Safety Profile
Pregnancy use-with-caution
Lactation insufficient-data
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.