BACKGROUND: To prevent hypertension and tachycardia after endotracheal intubation, esmolol and low-dose fentanyl have been used and it was reported that the combination of them was more effective than either in normotensive patients. However there have been few studies in this regard using hypertensive patients. Therefore, the author evaluated the effects of a combination of esmolol and low-dose fentanyl on hemodynamic responses after laryngoscopy and endotracheal intubation in hypertensive patients. METHODS: Thirty hypertensive patients were premedicated with midazolam and glycopyrrolate. Fentanyl 2 microgram/kg and esmolol 1 mg/kg were injected before induction of anesthesia. Thiopental sodium 3 5 mg/kg and succinylcholine 1 mg/kg were used for the induction of anesthesia. Endotracheal intubation was performed at 5 minutes after fentanyl injection. Thereafter 50% nitrous oxide in oxygen and 2 vol% enflurane were inhaled. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP) and heart rate (HR) were measured before fentanyl injection (base), before intubation, and at 1, 3 and 5 minutes after intubation. RESULTS: At 1 minute after intubation, SBP and MAP did not change significantly, but DBP increased slightly compared to base (P < 0.05). SBP, DBP and MAP decreased at 3 and 5 minutes after intubation (P < 0.05). HR did not change significantly. Hypertension (SBP>170 mmHg) developed in 2 patients at 1 minute after intubation, and hypotension (SBP<90 mmHg) in 3 patients at 5 minutes after intubation. Tachycardia (HR > 100 bpm) developed in 2 patents at 1 minute after intubation and bradycardia (HR< 50 bpm) in 1 patient at 5 minutes after intubation. CONCLUSIONS: In treated hypertensive patients, the use of a combination of fentanyl 2 microgram/kg and esmolol 1 mg/kg is a useful method to attenuate hypertension and tachycardia after endotracheal intubation.