CARDESINE (ADENOSINE) 6MG/2ML VIAL 6`S

Cardesine (adenosine) is a naturally occurring substance found in every cell of the human body. As an injectable medicine, it is used in emergency cardiac situations to rapidly terminate a type of abnormally fast heart rhythm called paroxysmal supraventricular tachycardia (SVT/PSVT) — a rapid, irregular heartbeat originating in the upper chambers of the heart.

Adenosine works within seconds by temporarily slowing electrical conduction through the heart's AV node, effectively 'resetting' the heart to a normal rhythm. Its extremely short half-life (less than 10 seconds) means any side effects are brief and transient. It is administered only in hospital with continuous cardiac monitoring and resuscitation equipment available.

Approved Uses

•     Rapid conversion to normal sinus rhythm of paroxysmal supraventricular tachycardia (PSVT/SVT) in adults and children — including SVT associated with Wolff-Parkinson-White (WPW) syndrome

•     Diagnostic aid in broad or narrow complex supraventricular tachycardias — helps identify the type of arrhythmia by revealing the underlying atrial activity

•     Adjunct to electrophysiological (intracavitary) investigations

Adults

•     Initial dose: 6 mg as a RAPID IV bolus over 1–3 seconds into a large peripheral vein (antecubital or larger), followed immediately by a 20 mL normal saline flush

•     If no conversion within 1–2 minutes: 12 mg IV bolus

•     If still no conversion: a second 12 mg dose may be given

•     Maximum total dose: 30 mg

Children (under 50 kg)

•     0.05–0.1 mg/kg as a rapid IV bolus. Maximum single dose: 0.3 mg/kg or 12 mg

Special Populations — REDUCE DOSE to 3 mg

•     Cardiac transplant recipients (adenosine sensitivity is greatly increased)

•     Patients on dipyridamole or carbamazepine

•     When administered via central venous access

CRITICAL: Administer only as a RAPID IV BOLUS — slow infusion is completely ineffective due to the drug's 10-second half-life.

Common — Almost Universal but Transient (lasting 10–30 seconds only)

•     Facial flushing, warmth or redness

•     Chest tightness or discomfort

•     Shortness of breath

•     Dizziness or lightheadedness

•     Nausea

•     Brief palpitations, sense of heart 'fluttering'

•     Transient ECG changes: bradycardia, brief pauses, or short runs of other rhythms — expected and self-limiting within seconds

Serious — Report to Medical Team

•     Severe bronchospasm: especially in patients with asthma — bronchodilators must be available

•     Prolonged asystole (cardiac standstill): rare but possible — most dangerous with dipyridamole co-administration

•     Ventricular arrhythmias: may be triggered in susceptible patients

•     Severe hypotension

•     Second- or third-degree AV block (without a functioning pacemaker)

•     Sick sinus syndrome (without a functioning pacemaker)

•     Severe asthma or bronchospasm — adenosine can trigger dangerous bronchospasm

•     Known hypersensitivity to adenosine

•     Concurrent dipyridamole use — potentiates adenosine 4-fold (risk of asystole); stop dipyridamole 24 hours before if essential

Asthma / COPD

CONTRAINDICATED in active bronchospasm. Use with extreme caution in any respiratory disease — have bronchodilators (salbutamol) available at bedside.

Cardiac Monitoring

Continuous ECG monitoring and full cardiorespiratory resuscitation equipment MUST be available during and after administration. A brief period of asystole after conversion is expected and usually self-terminating.

Pregnancy

Limited human data available. Adenosine is naturally present in the body and is not thought to pose significant fetal risk. Use only when benefit clearly outweighs risk.

•     Dipyridamole: ABSOLUTELY CONTRAINDICATED — inhibits adenosine breakdown, causing 4-fold potentiation. Risk of asystole.

•     Theophylline, aminophylline, caffeine (xanthines): Block adenosine receptors and completely antagonise its effect — avoid for 24 hours before adenosine administration

•     Carbamazepine: Enhances AV block effect — reduce adenosine dose to 3 mg

•     Beta-blockers, calcium channel blockers, digoxin: May potentiate AV conduction effects — use with caution and have resuscitation ready

•     Store below 25°C. Do NOT refrigerate or freeze (precipitation may occur)

•     Do not use if particulate matter or discolouration is present

•     For single use only — discard any unused solution immediately after use

POM — Prescription Only Medicine. Hospital emergency/cardiac use only. Requires continuous ECG monitoring and resuscitation availability.

The brief side effects you experience during adenosine administration — flushing, chest tightness, and shortness of breath — are expected and last only 10–30 seconds. They are caused by the drug momentarily slowing your heart and are not dangerous. Tell the medical team immediately if you have a history of asthma before receiving this medication.

•     Half-life is <10 seconds — must be administered as a very rapid IV bolus followed immediately by a saline flush to reach the central circulation before the drug is metabolised

•     SVT termination rate with standard dosing: approximately 90–95% for AV-nodal re-entrant tachycardia (AVNRT) and AV re-entrant tachycardia (AVRT); lower for other SVT types

•     Diagnostic value: Even when adenosine fails to terminate the rhythm, the transient AV block it causes reveals the underlying atrial activity on the ECG, aiding diagnosis

•     Xanthine antagonism: Patients who regularly consume high amounts of caffeine (strong coffee, energy drinks) may require higher doses — theophylline renders adenosine completely ineffective

•     Dipyridamole alert: Commonly used in pharmacological stress testing — check medication history before administration

•     Central line dosing: Halve the dose — drug reaches the heart faster via central access

Q: Why did I feel so strange when I received adenosine?

A: The flushing, chest tightness, and breathlessness you felt are common and expected with adenosine. They typically last only 10–30 seconds — no longer — because the drug is broken down extremely quickly in the body. These sensations are caused by the drug temporarily slowing your heart and are not a sign of danger.

Q: Will adenosine work every time my SVT comes back?

A: Adenosine is very effective (over 90% success rate) for the most common types of SVT that rely on a circuit running through the AV node. If your SVT is caused by a different mechanism, adenosine may help diagnose but not convert it. Discuss long-term rhythm management with your cardiologist.

Q: Can I go home right away after receiving adenosine?

A: No. You will be observed and monitored for a period after treatment to ensure your heart rhythm remains stable and normal. Your doctor will advise when it is safe to be discharged.