Adenosine

Question 1

Generic Name:

Answer 1

Adenosine

Question 2

Class:

Answer 2

Antiarrhythmic, endogenous nucleoside

Question 3

Mechanism of Action:

Answer 3

- Slows conduction time through AV node; can interrupt re-entrant pathways through the AV node.

- Slows sinus rate.

- Larger doses decrease BP by decreasing peripheral resistance.

Question 4

Indications and Field Use:

Answer 4

- Conversion of supraventricular tachycardias with no known atrial fibrillation or atrial flutter.

- Undifferentiated regular monomorphic wide-complex tachycardia

Question 5

Contraindications:

Answer 5

• Sick sinus syndrome, 2nd or 3rd degree AV blocks; except in patients with a functioning ventricular pacemaker.
  - Use cautiously in patients with known asthma (has precipitated acute bronchospasm).
  - Patients on theophylline and related methylxanthines.
  - Patients on dipyridamole (Persantine) or carbamazepine (Tegretol).
  - Cardiac transplant patients are more sensitive to adenosine and require only a small dose
  (relative).
  - Known atrial fibrillation or atrial flutter.
  - Pregnancy (no controlled studies)

Question 6

Adverse Reactions:

Answer 6

CV: Transient dysrhythmias (systole, bardycardia, PVC’s) occur in 55% of patients (none reported as irreversible). Palpitations, chest pressure, chest pain, hypotension, transient hypertension; facial flushing, sweating.

Resp: Dyspnea, hyperventilation, tightness in throat, bronchospasm.

CNS: Lightheadedness, headache, dizziness, paresthesias, apprehension, blurred vision,
neck-back pain.

GI: Nausea, metallic taste.

Question 7

Incompatibilities/Drug Interactions:

Answer 7

• Adenosine is not blocked by Atropine.
  - Theophylline and related methylxanthines (caffeine & theobromine-xanthine) in therapeutic concentrations decrease effectiveness. See: CONTRAINDICATIONS
• Dipyridamole (Persantine) & carbamazepine (Tegretol, Atretol) block uptake and potentiate effects. See: CONTRAINDICATIONS.

Question 8

Adult Dosage:

Answer 8

• Initial: 6 mg rapid IV bolus over 1-3 seconds
  - Special administration procedure: Follow immediately with 20 ml normal saline flush. IV site recommended is antecubital fossa (close to central circulation); use injection port nearest hub of IV catheter; arm elevated during procedure; constant ECG monitoring.
  - Repeat: If no response in 1-2 minutes (of each dose, respectively) may repeat 12 mg
  utilizing the same procedure for the repeat dose.

Question 9

Pediatric Dosage: (Drug of choice for treating SVT in symptomatic infants and children)

Answer 9

• Initial: 0.1 mg/kg as a rapid IV bolus.
  - Special administration procedure: Follow immediately with 2-3 ml normal saline flush. Use injection port nearest the hub of IV catheter for procedure; constant ECG monitoring.
  - Repeat: If no response, dose may be doubled 1 time (0.2 mg/kg) using same administration procedure.
  - Maximum single 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 10

Routes of Administration:

Answer 10

Rapid IV push

Question 11

Onset of Action:

Answer 11

Seconds

Question 12

Duration of Action:

Answer 12

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

Question 13

Arizona Drug Box Minimum Supply:

Answer 13

18mg

Question 14

Special Notes:

Answer 14

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

Question 15

Trade Name:

Answer 15

Adenocard

Question 16

Supplied:

Answer 16

6mg/2ml vial

12mg/4mL pre-filled syringes