adenosine

General

Pronunciation
a-DEN-oh-seen [Pronunciation]

Trade Name(s)

• Adenocard

• Adenoscan

Pregnancy Category
Category C

Ther. class.
antiarrhythmics

Indications

• Conversion of paroxysmal supraventricular tachycardia (PSVT) to normal sinus rhythm when vagal maneuvers are unsuccessful.

• As a diagnostic agent (with noninvasive techniques) to assess myocardial perfusion defects occurring as a consequence of coronary artery disease.

Action

• Restores normal sinus rhythm by interrupting re-entrant pathways in the AV node.

• Slows conduction time through the AV node.

• Also produces coronary artery vasodilation.

Therapeutic Effect(s):
Restoration of normal sinus rhythm.

Pharmacokinetics

Absorption: Following IV administration, absorption is complete.

Distribution: Taken up by erythrocytes and vascular endothelium.

Metabolism and Excretion: Rapidly converted to inosine and adenosine monophosphate.

Half-life: <10 sec.

TIME/ACTION PROFILE (antiarrhythmic effect)

ROUTE	ONSET	PEAK	DURATION
IV	immediate	unknown	1–2 min

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity;

• 2nd- or 3rd-degree AV block or sick sinus syndrome, unless a functional artificial pacemaker is present.

Use Cautiously in:

• Patients with a history of asthma (may induce bronchospasm);

• Unstable angina;

• OB: Lactation: Safety not established.

Adverse Reactions/Side Effects

CNS: apprehension, dizziness, headache, head pressure, light-headedness.

EENT: blurred vision, throat tightness.

Resp: shortness of breath, chest pressure, hyperventilation.

CV: facial flushing, transient arrhythmias, chest pain, hypotension, palpitations.

GI: metallic taste, nausea.

Derm: burning sensation, facial flushing, sweating.

MS: neck and back pain.

Neuro: numbness, tingling.

Misc: heaviness in arms, pressure sensation in groin.

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug

• Carbamazepine may ↑ risk of progressive heart block.

• Dipyridamole ↑ effects of adenosine (dose ↓ of adenosine recommended).

• Effects of adenosine ↓ by theophylline or caffeine (↑ doses of adenosine may be required).

• Concurrent use with digoxin may ↑ risk of ventricular fibrillation.

Route/Dosage

• IV (Adults and Children >50 kg): Antiarrhythmic—6 mg by rapid IV bolus; if no results, repeat 1–2 min later as 12-mg rapid bolus. This dose may be repeated (single dose not to exceed 12 mg). Diagnostic use—140 mcg/kg/min for 6 min (0.84 mg/kg total)..

• IV (Children <50 kg): Antiarrhythmic—0.05–0.1 mg/kg as a rapid bolus, may repeat in 1–2 min; if response is inadequate, may increase by 0.05–0.1 mg/kg until sinus rhythm is established or maximum dose of 0.3 mg/kg is used..

Availability

• Injection: 6-mg/2-mL vial (Adenocard), 3 mg/1 mL in 30-mL vial (Adenoscan)

Assessment

• Monitor heart rate frequently (every 15–30 sec) and ECG continuously during therapy. A short, transient period of 1st-, 2nd-, or 3rd-degree heart block or asystole may occur following injection; usually resolves quickly due to short duration of adenosine. Once conversion to normal sinus rhythm is achieved, transient arrhythmias (premature ventricular contractions, atrial premature contractions, sinus tachycardia, sinus bradycardia, skipped beats, AV nodal block) may occur, but generally last a few seconds.

• Monitor BP during therapy.

• Assess respiratory status (breath sounds, rate) following administration. Patients with history of asthma may experience bronchospasm.

Potential Nursing Diagnoses

• Decreased cardiac output (Indications)

Implementation

IV Adminstration:

• pH:
4.5–7.5.

• IV:
Crystals may occur if adenosine is refrigerated. Warm to room temperature to dissolve crystals. Solution must be clear before use. Do not administer solutions that are discolored or contain particulate matter. Discard unused portions.

• Direct IV:

Diluent: Administer undiluted.
Concentration: 3 mg/mL.

• Rate:
Administer over 1–2 seconds via peripheral IV as proximal as possible to trunk. Slow administration may cause increased heart rate in response to vasodilation. Follow each dose with 20 mL rapid saline flush to ensure injection reaches systemic circulation.

• Intermittent Infusion:
(for use in diagnostic testing)
Diluent: Administer 30-mL vial undiluted.
Concentration: 3 mg/mL.

• Rate:
Administer at a rate of 140 mcg/kg/min over 6 min for a total dose of 0.84 mg/kg. Thallium-201 should be injected as close to the venous access as possible at the midpoint (after 3 min) of the infusion.

Patient/Family Teaching

Caution patient to change positions slowly to minimize orthostatic hypotension. Doses >12 mg decrease BP by decreasing peripheral vascular resistance.

» Instruct patient to report facial flushing, shortness of breath, or dizziness.