Methods: The investigators administered a proposed maximum recommended dose (18 mg tetracaine/0.3 mg oxymetazoline) as three bilateral pairs of 0.1 ml nasal sprays. Double this dose as six bilateral sprays was administered 1-3 weeks later. Heart rate, blood pressure and oxygen saturation were recorded. Blood samples were drawn at baseline and for two hours following drug administration.
Results: Physiologic measures remained fairly stable throughout the two-hour period, with small but significant decreases (p < 0.05) in HR at 40 and 50 min for the 2X MRD (6.1 beats/min) and MRD (7.5 beats/min) regimens respectively, and a significant increase in DBP for the 2X MRD at 90 minutes (5.9 mm Hg). Mean SpO2 remained above 99%. Tetracaine plasma levels were undetectable in most subjects, whereas concentrations of its major metabolite PBBA from the 36 /0.6 mg dose, were approximately double that of the 18/0.3 mg dose. Oxymetazoline concentrations from the 36/0.6 mg dose were approximately 50% greater than that from the 18/0.3 mg dose with a half life of 1.72 - 2.32 hours.
Conclusions: Intranasal tetracaine/oxymetazoline mist was generally well tolerated. Additional safety and efficacy data is required, particularly in patients with cardiovascular disease and other co-morbidities.
This study was supported by a grant from St Renatus LLC.