A preliminary study of cocaine absorption from the nasal mucosa

Objective/Hypothesis: To determine factors affecting the safe use of topica l cocaine for anesthesia and vasoconstriction during rhinologic surgery. St udy Design: Prospective, randomized study of the kinetics of cocaine absorp tion through human nasal mucosa in 12 consecutive patients without nasal mu cosal disease who were having septoplasty or septorhinoplasty. Methods: Wit h patients under general anesthesia, cocaine was applied topically to each nasal cavity by using cottonoid pledgets. Group I received 4 mL of a 4% sol ution (160 mg) of cocaine for 10 min, Group II received 4 mt of a 4% soluti on (160 mg) of cocaine for 20 min, and Group Ill received 4 mL of a 10% sol ution (400 mg) of cocaine for 20 min. Absorption rate was determined by mea suring serum cocaine concentration at intervals of 5, 10, 15, and 20 min. R esidual cocaine was extracted from the pledgets and was analyzed quantitati vely by using gas chromatography and mass spectroscopy, Results: Of total c ocaine applied, 35% was absorbed systemically: 17% was absorbed within 5 mi n, 25% within 10 min, and 32% within 15 min, Of the cocaine absorbed, 47% w as absorbed within the first 5 min, 70% within 10 min, and 90% within 15 mi n. Two patients (16.6%), both in Group III, had intraoperative hypertension ; one of these patients also had transient ventricular tachycardia Conclusi ons: Although a 4% solution of cocaine applied to the nasal mucosa on cotto noid pledgets for 20 min is safe, we observed an idiosyncratic absorption r ate four times greater than expected; therefore, we advise against topical use of a 10% cocaine solution for anesthesia and vasoconstriction during rh inologic surgery.