Adenosine (Adenocard)

Question 1

Drug Classification

Answer 1

Antidysrhythmic (class V)/nucleoside

Question 2

Mechanism of Action

Answer 2

Adenosine(A1) R agonist->slows AV conduction by activation of G protein second messenger, decreasing cAMP and inhibiting calcium entry into the cardiac pacemaker cells.

Question 3

Pharmacokinetics

Answer 3

• Onset of Action- immediate
• Peak Effects- immediate
• Duration of Effects- 30-45 seconds
• Half Life- 6 seconds

Question 4

Indications/Field Use

Answer 4

• SVT (PSVT)/ Narrow Complex Tachycardia
• Diagnostic maneuver: stable narrow complex SVT
• Wide regular monomorphic tachycardia

Question 5

Contraindications

Answer 5

• 2/3 degree heart block, sick sinus syndrome, Torsades (Polymorphic VT)
• Poison/Chemical induced SVT (ie. Cocaine)

Question 6

Side Effects/Adverse Reactions

Answer 6

Facial Flushing, HA, chest pain, dizziness

Question 7

Dose

Answer 7

Adult:
1st dose- 6mg rapid IVP (proximal vein) followed by 30cc NS flush
2nd dose- 12mg rapid IVP followed by 30cc NS flush

Pedi:
1st dose - 0.1mg/kg IV/IO rapid push (proximal vein), max dose 6 mg
2nd dose - 0.2mg/kg IV/IO rapid push IV/IO rapid push, max dose 12mg

Question 8

Precautions

Answer 8

• Begin printing rhythm strip before administering adenosine
• Caution with asthma and COPD- may induce wheezing

Question 9

Drug-drug interactions

Answer 9

• Methylxanthines (ie. caffeine) are nonspecific competitive antagonists for adenosine receptors- double the dose for patients taking large amounts
• Carbamazepines (ie. Tegretol, Phenobarbitol) and dipyridamole (Persantine, Aggrenox) potentiates effects of Adenosine- halve the dose