Adenosine

Question 1

Class?

Answer 1

Antiarrhythmic; endogenous nucleoside

Question 2

Mechanism of action?

Answer 2

• Slows construction time through AV node. Can interrupt re-entrant pathways through the AV node.
• Slows sinus rate.
• Larger doses decreases BP by decreasing peripheral resistance.

Question 3

Indications and Field Use?

Answer 3

• Conversion of supraventricular tachycardias with no known atrial fibrillation or atrial flutter.
• Undifferentiated regular monomorphic wide-complex tachycardia. SVT

Question 4

Contraindications?

Answer 4

• Sick sinus syndrome, 2nd or 3rd degree heart blocks; except in pts with a functioning ventricular pacemaker.
• use cautiously in pts with known asthma (has precipitated acute bronchospasm)
• Pts on theophylline and related methylxanthines, dipyridamole (Persantine) or carbamazepine (Tegretol).
• Cardiac transplant pts are sensitive and require only a small dose.
• Known Afib or Aflutter
• Pregnancy (no controlled studies)

Question 5

Adverse Reactions?

Answer 5

• CV: Transient dysrhythmias, palpitations, chest pressure, chest pain, hypotension, transient hypertension, facial flushing, sweating
• Resp: Dyspnea, hyperventilation, tightness in throat, bronchospasm.
• CNS: Lightheadedness, headache, dizziness, parenthesis, apprehension, blurred vision, neck back pain.
• GI: Nausea, metallic taste.

Question 6

Incompatibilities/drug interactions?

Answer 6

Adenosine is not blocked by Atropine.

See Contraindications.

Question 7

Adult Dosage?

Answer 7

*Initial: 6mg rapid IV bolus over 1-3 seconds.
Follow immediately with 20 ml normal saline flush.
*Repeat: if no response in 1-2 minutes, may repeat 12 mg utilizing the same procedure for the repeat dose.

Question 8

Pediatric Dosage?

Answer 8

*Initial: 0.1 mg/kg as a rapid IV bolus.
Follow immediately with 2-3 ml normal saline flush.
*if no response, dose may be doubled 1 time (0.2 mg/kg) using same administration procedure.
*Max dose: should not exceed 12 mg.
*Infants with SVT associated with shock: Adenosine may precede cardioversion if vascular access is available, but cardioversion should not be delayed while IV access is achieved.

Question 9

Routes of administration?

Answer 9

Rapid IV Push

Question 10

Onset of action?

Answer 10

Seconds

Question 11

Duration of action?

Answer 11

10-12 seconds (1/2 life 5 seconds)

Question 12

AZ Drug Box minimum supply?

Answer 12

18 mg

Question 13

Special notes?

Answer 13

• Dysrhythmias may recur (short half life)
• Dysrhythmias appear in 55% of patients at conversion, leading for a few seconds, do not usually require intervention.
• second dose must be prepared and available
• check for crystallization in cold climates