Which drug prevents tachycardia and hypertension associated with tracheal intubation: lidocaine, fentanyl, or esmolol? Eighty patients, ASA physical status II-IV, scheduled for noncardiac surgery, were randomly assigned in a double-blind, placebo-controlled manner to receive a preintubation dose of either placebo, 200 mg lidocaine, 200 micrograms fentanyl, or 150 mg esmolol. Induction of anesthesia was accomplished with 4-6 mg/kg thiopental IV followed immediately by the study drug; 1-1.5 mg/kg succinylcholine was given at minute 1. Laryngoscopy and intubation were performed at minute 2 with anesthesia thereafter maintained with 1 MAC (+/- 10%) isoflurane in 60% nitrous oxide in oxygen at a 5 L/min flow for 10 min. Heart rate was recorded every 15 s and blood pressure every minute from induction until 10 min after intubation. Maximum percent increases in heart rate (mean +/- SE) during and after intubation were similar in the placebo (44% +/- 6%), lidocaine (51% +/- 10%), and fentanyl (37% +/- 5%) groups, but lower in the esmolol (18% +/- 5%) group (P less than 0.05). Maximum systolic blood pressure percent increases were lower in the lidocaine (20% +/- 6%), fentanyl (12% +/- 3%), and esmolol (19% +/- 4%) groups than in the placebo (36% +/- 5%) group (P less than 0.05), but not different from each other (P greater than 0.05). Only esmolol provided consistent and reliable protection against increases in both heart rate and systolic blood pressure accompanying laryngoscopy and intubation. 