For patients with stage 2 hypertension before operation, it is difficult to maintain the recommended blood pressure during surgery using only intravenous sedation, and it is necessary to decrease blood pressure by antihypertensive drugs. In this study, the blood pressure of patients with sustained hypertension was reduced to stage I hypertension about 30 min after administration of oral nifedipine. On the other hand, the decrease in RPP after oral nifedipine administration was not less than 12,000 bpm × mmHg, which could be due to the fact that an increase in pulse rate with nifedipine by reflex tachycardia. Thereafter, blood pressure and RPP during surgery under intravenous sedation has remained at levels similar to those of hypertensive patients with well-controlled blood pressure. Maximum effect (21.4% decreases in SBP) appears in 30 to 60 min and lasts about 3 h on oral administration of nifedipine [12]. The half-lives of oral nifedipine, diltiazem and verapamil, and calcium antagonists are 0.2 to 1 h, 6 to 8 h, and 6 to 8 h, respectively [13]. Since oral nifedipine has the properties of fast onset (30 to 45 min) [14] and relatively short duration, it is suitable for outpatient dental implant surgery and is useful in perioperative management of patients with hypertension.

The overdose of vasoconstrictor that is added to the local anesthetic in order to prolong the anesthetic effect and hemostatic action may cause increased blood pressure and arrhythmias. Elevation of blood pressure in hypertensive patients is greater than that in normotensive patients during dental surgery [15]. Although there is an increase in blood pressure and tachycardia when using three cartridges of local anesthetic containing epinephrine 1:10,000 (5.4 ml), there are no adverse symptoms in patients with normal blood pressure [16]. Little recommended that the amount of local anesthetic solution administered should be less than two cartridges (3.6 ml) for patients with hypertension [1]. Nakamura et al. reported that patients with essential hypertension who have been administered nifedipine can receive less than 3.6 cartridges of local anesthetic containing epinephrine 1:80,000 (6.4 ml) [17]. The administration of exogenous epinephrine with local anesthesia produces the highest plasma concentration in 3 to 6 min and lasts for 20 min [18]. It has been reported that the anesthetic rate of 2% lidocaine containing 1:10,000 epinephrine is 47% 45 min after administration and 27% 60 min after administration [19]. During dental implant surgery which requires a relatively long duration and a wide field in patients with hypertension, administration of conduction anesthesia including inferior alveolar block and posterior superior alveolar nerve block is desirable. When the patient complains of pain, it is important to add local anesthesia while monitoring blood pressure to prevent increased blood pressure caused by pain.