Alternatives to Adenocard If You Can't Fill Your Prescription

Adenocard (adenosine injection) is the go-to drug for converting paroxysmal supraventricular tachycardia (PSVT) in emergency and hospital settings, and it plays a key role in pharmacologic stress testing for patients who can't exercise. But what happens when adenosine is not available — whether due to a supply disruption, a contraindication, or a patient's history of severe reactions?

The good news: evidence-based alternatives exist for both PSVT management and stress testing. This guide breaks down the options, compares their effectiveness, and explains when each is most appropriate.

Why Would a Patient or Clinician Need an Adenocard Alternative?

There are several reasons a clinical team might need to turn to an adenosine alternative:

• Adenosine supply is unavailable or on back-order at the facility's distributor
• Patient has a known contraindication: severe asthma, active bronchospasm, second/third degree heart block (without pacemaker), or hypersensitivity to adenosine
• Patient previously experienced a severe adverse reaction (extreme chest pain, prolonged asystole, seizure)
• Patient is on high-dose theophylline or caffeine, which block adenosine's therapeutic effect
• Stress test imaging requires an alternative pharmacologic stressor

Alternative #1: Verapamil IV — The Original First-Line Agent

Before adenosine was approved by the FDA in 1989, IV verapamil was the standard first-line treatment for PSVT. It works by blocking L-type calcium channels in the AV node, slowing conduction and interrupting the reentry circuit — the same functional endpoint as adenosine, but through a different mechanism.

Efficacy: Meta-analyses show PSVT conversion rates of approximately 89–92% for verapamil, essentially equivalent to adenosine (~90%). The AHA continued to recommend adenosine as first-line primarily due to adenosine's lower risk of hemodynamic compromise (it clears in under 10 seconds vs. verapamil's 3–6 hour half-life).

Standard dosing: 5 mg IV over 2 minutes; may repeat 5–7.5 mg in 5–10 minutes if no conversion. Maximum 20 mg total.

Key caveat: Avoid in patients with impaired left ventricular function, wide-complex tachycardia of uncertain origin, or those concurrently on beta-blockers (risk of profound bradycardia/AV block). Also contraindicated in Wolff-Parkinson-White (WPW) syndrome.

Alternative #2: Diltiazem IV — A Well-Tolerated Calcium Channel Blocker

Diltiazem is another non-dihydropyridine calcium channel blocker with FDA approval for PSVT conversion. Studies have shown conversion rates as high as 96–100% with slow-infusion diltiazem. A 2025 multicenter cohort study published in the Journal of Emergency Medicine found that diltiazem and adenosine had similar overall conversion rates in the ED, and diltiazem effectively rescued cases that did not respond to adenosine.

Standard dosing: 0.25 mg/kg (approximately 15–20 mg) IV over 2 minutes. If needed, a second dose of 0.35 mg/kg (25–35 mg) may be given in 15 minutes. A continuous infusion of 5–15 mg/hour can maintain rate control.

Advantage over verapamil: Diltiazem is associated with a lower risk of hypotension than verapamil when given as a slow infusion. One study of 206 patients found only 1 of 102 patients on calcium channel blockers developed hypotension, with none in the adenosine group.

Alternative #3: Regadenoson (Lexiscan) — For Pharmacologic Stress Testing

For patients who need a nuclear stress test but cannot exercise, adenosine (Adenoscan) is one option — but regadenoson (Lexiscan) is an FDA-approved alternative pharmacologic stressor. Regadenoson is a selective A2A adenosine receptor agonist given as a single 0.4 mg IV bolus. It is less likely to cause bronchospasm than adenosine because it acts more selectively on the A2A receptor rather than all adenosine receptor subtypes.

Regadenoson is now the most widely used pharmacologic stress agent in the U.S. and has largely replaced adenosine (Adenoscan) at many nuclear cardiology programs due to its simplified bolus dosing and better tolerability in patients with mild reactive airway disease.

Alternative #4: Beta-Blockers — For Long-Term SVT Prevention

Beta-blockers like metoprolol (oral or IV) and esmolol (IV, ultra-short acting) are not used to acutely convert PSVT in the same way adenosine does, but they play an important role in preventing SVT recurrence. For patients with recurrent PSVT, long-term oral beta-blockers or calcium channel blockers are often prescribed between episodes. IV esmolol (with its 9-minute half-life) can be used for rate control in stable patients when other agents are contraindicated.

Alternative #5: Vagal Maneuvers — The Non-Drug Option

Before any drug is given, AHA guidelines recommend attempting vagal maneuvers. The Valsalva maneuver — bearing down as if having a bowel movement — can terminate PSVT in 19–54% of cases when performed correctly. The modified Valsalva with leg elevation and immediate supine positioning (Appelboam technique) has demonstrated conversion rates as high as 43% in clinical trials. This is always the best first step when the patient is hemodynamically stable.

Comparing the Alternatives: A Quick Reference

For acute PSVT conversion: Adenosine first → IV diltiazem or verapamil if adenosine fails or is unavailable → Synchronized cardioversion for unstable patients

For pharmacologic stress testing: Adenosine (Adenoscan) → Regadenoson (Lexiscan) if adenosine unavailable or contraindicated

For long-term SVT prevention: Oral verapamil, diltiazem, or beta-blockers → Catheter ablation for definitive cure

If Adenocard Is Out of Stock, Don't Wait to Act

If your facility is having trouble sourcing adenosine injection, use medfinder to find which pharmacies and distributors have it in stock near you. And for more background on why adenosine supply can fluctuate, read our guide: Why Is Adenocard Hard to Find?