• Toxic effects were observed in two healthy patients who received cocaine intranasally before dacryocystorhinostomy. One patient suffered an additional reaction to intranasally administered phenylephrine (Neo-Synephrine) hydrochloride. Because cocaine blocks uptake of catecholamines and has a sympathetic potentiating effect, its use is dangerous in patients with hypertensive cardiovascular disease or in conjunction with sympathomimetic or α-modifying drugs. Use of dilute solutions carefully measured for select patients is mandatory. The total dose of cocaine should not exceed 3 mg/kg.
Meyers EF. Cocaine Toxicity During Dacryocystorhinostomy. Arch Ophthalmol. 1980;98(5):842-843. doi:10.1001/archopht.1980.01020030836006