Topical nitroglycerin and lidocaine locally vasodilate the radial artery without affecting systemic blood pressure: a dose-finding phase I study.
OBJECTIVE
Small radial artery diameter (RAD) and vasospasm are barriers to radial artery cannulation. We performed this study to determine if topical nitroglycerin and/or nitroglycerin plus topical lidocaine increases RAD without affecting systemic blood pressure.


METHODS
This was a randomized, double-blind, placebo-controlled study. In the first visit, to determine the optimal dose of nitroglycerin, subjects were randomized to either 15 or 30 mg nitroglycerin on one wrist and placebo on the other. In visit 2, to assess for any effect of lidocaine on the vasodilator function of nitroglycerin, the same subjects were randomized to 20 mg lidocaine + 30 mg nitroglycerin vs 20 mg lidocaine + placebo, or 40 mg lidocaine + 30 mg nitroglycerin vs 40 mg lidocaine + placebo. In both visits, blood pressure and RAD using ultrasonography were measured for 2 hours.


RESULTS
In visit 1, both nitroglycerin groups significantly increased RAD, with greater increases with 30 mg nitroglycerin (P < .01) and no significant increase in RAD in placebo wrists. In visit 2, increase in RAD was significantly greater with 20 mg lidocaine + 30 mg nitroglycerin vs 20 mg lidocaine + placebo (P < .001), and 40 mg lidocaine + 30 mg nitroglycerin vs 40 mg lidocaine + placebo (P < .001), indicating that lidocaine does not alter the effect of nitroglycerin. There were significant increases in RAD seen as early as 30 minutes. There were no significant change in RAD in lidocaine + placebo-treated wrists and no change in blood pressure in any group.


CONCLUSIONS
Topical nitroglycerin and lidocaine significantly increase RAD within 30 to 60 minutes with no effect on contralateral radial artery or blood pressure, indicating a direct, local effect on the radial artery. (Clinicaltrials.gov number NCT00686231).
Department of Medicine, Division of Cardiology, University of California San Francisco, San Francisco, CA 94143, USA.
David T
DT
Majure
Melanie
M
Hallaux
Yerem
Y
Yeghiazarians
Andrew J
AJ
Boyle
D000287:Administration, Topical; D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology; D017023:Coronary Angiography / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004347:Drug Interactions; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D005996:Nitroglycerin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D017534:Radial Artery / Q000187:drug effects*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
D000779:Anesthetics, Local; D014665:Vasodilator Agents; D008012:Lidocaine; D005996:Nitroglycerin