Adenosine

CLASS

• short acting anti-arrhythmic
• naturally occurring purine nucleoside

MECHANISM OF ACTION

• depression of SA & AV nodal activity
• antagonises cAMP-mediated catecholamine stimulation of ventricular muscle

-> negative chronotropy & dromotropy

• direct agonist at specific cell membrane receptors (A1 & A2)
• A1 = coupled to K+ channels by a guanine nucleotide-binding protein in supraventricular tissue.

PHARMACEUTICS

• clear, colourless
• 3mg/mL
• in saline

DOSE

• rapid IV bolus followed by saline flush
• 3mg -> 6mg -> 12mg (adult)
• 0.04 to 0.25mg/kg (children)

INDICATIONS

• diagnosis and treatment of paroxysmal SVT

ADVERSE EFFECTS

• bronchospasm
• flushing
• SOB
• chest pain

CONTRAINDICATIONS

• second and third degree AV block
• allergy
• care with asthma and COPD

PHARMACOKINETICS

• Onset – 10 seconds
• Duration – 10 seconds

• Absorption – must be given IV
• Distribution
• Metabolism – absorbed by RBC’s and endothelium
• Elimination – t ½ = 10 seconds