Adenoscan

Action

Converts paroxysmal supraventricular tachycardia (PSVT) to normal sinus rhythm by slowing conduction through atrioventricular (AV) node and interrupting reentry pathway. Also used as a diagnostic agent in thallium scanning.

Availability

Injection: 3 mg/ml

Indications and dosages

Adenocard-

➣ PSVT, including that associated with Wolff-Parkinson-White syndrome (after attempting vagal maneuvers, when appropriate)

Adults and children weighing more than 50 kg (110 lb): Initially, 6 mg by rapid I.V. bolus over 1 to 2 seconds. If desired effect isn't achieved within 1 to 2 minutes, give 12 mg by rapid I.V. bolus; may repeat 12-mg I.V. bolus dose as needed. Maximum single dosage is 12 mg.

Children weighing less than 50 kg (110 lb): 0.05 to 0.1 mg/kg by rapid I.V. bolus. If this dosage proves ineffective, increase in 1 to 2 minutes by 0.05 mg/kg q 2 minutes, to a maximum single dosage of 0.3 mg/kg. Maximum single dosage is 12 mg.

Adenoscan-

➣ Diagnosis of coronary artery disease in conjunction with thallium-201 myocardial perfusion scintigraphy in patients unable to exercise adequately during testing

Adults: 140 mcg/kg/minute by I.V. infusion over 6 minutes, for a total dosage of 0.84 mg/kg. Required dose of thallium-201 is injected at midpoint (after first 3 minutes) of Adenoscan infusion.

Off-label uses

• Diagnosis of supraventricular arrhythmias

• Pulmonary hypertension

Contraindications

• Hypersensitivity to drug

• Second- or third-degree AV block

• Sinus node disease

• Bronchoconstrictive lung disease

Precautions

Use cautiously in:

• asthma, angina

• elderly patients

• pregnant patients

• children.

Administration

• Don't administer through central line (may cause asystole).

• Don't give more than 12 mg Adenocard as a single dose.

• Don't dilute Adenocard. Administer Adenocard by I.V. injection as a rapid bolus directly into vein whenever possible during cardiac monitoring.

• After administering Adenocard, flush I.V. line immediately and rapidly with normal saline solution to drive drug into bloodstream.

• Dilute a single dose of Adenoscan in sufficient normal saline solution to be given by continuous infusion over 6 minutes.

Adverse reactions

CNS: light-headedness, dizziness, apprehension, headache, tingling in arms, numbness

CV: chest pain, palpitations, hypotension, ST-segment depression, first- or second-degree AV block, atrial tachyarrhythmias, other arrhythmias

EENT: blurred vision, tightness in throat

GI: nausea, pressure in groin

Musculoskeletal: discomfort in neck, jaw, and arms

Respiratory: chest pressure, dyspnea and urge to breathe deeply, hyperventilation

Skin: burning sensation, facial flushing, sweating

Other: metallic taste

Interactions

Drug-drug. Carbamazepine: worsening of progressive heart block

Digoxin, verapamil: increased risk of ventricular fibrillation

Dipyridamole: increased adenosine effect

Theophylline: decreased adenosine effect

Drug-food. Caffeine: decreased adenosine effect

Drug-herbs. Aloe, buckthorn bark or berry, cascara sagrada, rhubarb root, senna leaf or fruits: increased adenosine effect

Guarana: decreased adenosine effect

Drug-behaviors. Smoking: increased risk of tachycardia

Patient monitoring

• Monitor heart rhythm for new arrhythmias after administering dose.

• Check vital signs. Assess for chest pain or pressure, dyspnea, and sweating.

See Watch for bronchoconstriction in patients with asthma, emphysema, or bronchitis.

• Ask patient if he has recently used aloe, buckthorn, cascara sagrada, guarana, rhubarb root, or senna. If response is positive, notify prescriber.

Patient teaching

• Advise patient to report problems at infusion site.

• Tell patient he may experience 1 to 2 minutes of flushing, chest pain and pressure, and breathing difficulty during administration. Assure him that these effects will subside quickly.

• Advise patient to minimize GI upset by eating small, frequent servings of healthy food and drinking plenty of fluids.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, foods, herbs, and behaviors mentioned above.