What is the recommended dosage of heparin, nitroglycerine, and diltiazem in a cocktail for radial access procedures?

Radial Access Cocktail: Recommended Dosages

For transradial access procedures, administer intra-arterially after sheath insertion: diltiazem 2.5-5 mg (or verapamil 2.5-5 mg), nitroglycerin 100-200 μg, and unfractionated heparin 50 U/kg up to 5000 U. 1

Antispasmolytic Agents (Administered Intra-arterially After Sheath Insertion)

Calcium Channel Blocker Options:

• Diltiazem: 2.5-5 mg 1
• Alternative: Verapamil 2.5-5 mg 1
• Alternative: Nicardipine 250-500 μg 1

Nitroglycerin:

• Dose: 100-200 μg 1
• Should be coadministered with calcium channel blockers due to short pharmacological half-life 1
• Can be repeated with catheter exchanges or before sheath removal 1

Practical Administration Technique:

• Dilute medications in 10-20 mL of blood aspirated from the sheath to prevent patient discomfort during injection 1, 2
• Administer through the sideport of the sheath 1

Anticoagulation (Mandatory for All Patients)

Unfractionated Heparin:

• Dose: 50 U/kg up to maximum 5000 U 1
• Should be administered to all patients, including those already on therapeutic oral anticoagulation 1
• Primary purpose is prevention of radial artery occlusion 1
• Higher doses (100 U/kg) may be superior to standard dosing for preventing radial artery occlusion 1

Alternative Anticoagulants:

• Comparable doses of enoxaparin or bivalirudin may be used 1

Critical Safety Considerations

Contraindications and Cautions:

• Exercise extreme caution with spasmolytics in patients with: 1
  • Cardiogenic shock
  • Severely reduced ejection fraction
  • Severe aortic stenosis
  • Systolic blood pressure <90 mmHg 3
• Avoid nitroglycerin in patients who have taken phosphodiesterase inhibitors (sildenafil within 24 hours, tadalafil within 48 hours) 3

Timing of Administration:

• Administer spasmolytic cocktail after sheath insertion 1
• May repeat with each catheter exchange 1
• Consider additional dose before sheath removal 1

Evidence Supporting This Regimen

The American Heart Association guidelines provide the strongest evidence base for these specific dosing recommendations, demonstrating that this combination reduces radial artery spasm rates from 15-30% without prophylaxis to 6-10% with appropriate spasmolytic cocktail administration 1. The combination of calcium channel blocker plus nitroglycerin is superior to either agent alone due to complementary mechanisms of action and the short half-life of nitroglycerin 1.

Research data supports that verapamil 5 mg plus nitroglycerin 200 μg reduces spasm incidence to 3.8% compared to 20.4% with heparin alone 4. However, some studies show nitroglycerin alone (100-200 μg) may be sufficient, with no additional benefit from adding diltiazem 5, 4.

Common Pitfalls to Avoid

• Do not omit heparin even in anticoagulated patients, as it specifically prevents radial artery occlusion 1
• Do not use excessive nitroglycerin (>200 μg) as this increases hypotension risk without additional benefit 3
• Do not administer spasmolytics before assessing hemodynamic stability in acute coronary syndrome patients 3
• Do not forget to readminister with catheter exchanges during prolonged procedures 1

Adjunctive Non-Pharmacological Measures

• Maintain warm environment and apply warm compresses to reduce sympathetic tone 6
• Provide adequate analgesia and sedation (low-dose fentanyl/midazolam combination reduces spasm from 8.3% to 2.6%) 1
• Use topical lidocaine for arterial puncture site 1