Effect of beta-adrenoreceptor blockade with nadolol on the duration of local anesthesia

Background. beta-adrenoreceptor blockers, or beta-blockers, are drugs commo nly prescribed for hypertension, angina and migraine headaches. In a patien t taking beta-blocker medication, administration of a local anesthetic cont aining a vasoconstrictor could result in an adverse interaction. Methods. T he authors conducted a double-blind, randomized, crossover, placebo-control led study to test the hypothesis that a nonselective beta-blocker-nadolol-e nhances vasoconstriction induced by the epinephrine contained in local anes thetic, thus resulting in an increased duration of anesthesia. Ten healthy male volunteers were given either a placebo or a single, standard oral dose of nadolol (80 milligrams). The upper lateral incisor teeth were anestheti zed using lidocaine with or without epinephrine. Results. The mean duration of pulpal and soft-tissue anesthesia was increased in subjects who took na dolol compared with those who took placebo by 17 minutes (58 percent) and 1 6.5 minutes (19 percent), respectively, when they received 1 milliliter of lidocaine containing 1:100,000 epinephrine. These differences were both cli nically and statistically significant (P = .007). Using Lidocaine without e pinephrine produced no clinically or statistically significant difference i n duration of pulpal or soft-tissue anesthesia in the two groups of subject s. The authors noted no significant changes in blood pressure or pulse-rate . Conclusions, Administration of local anesthetic containing epinephrine to s ubjects receiving a beta-blocker increased the duration of pulpal and soft- tissue anesthesia. There was no difference in duration of anesthesia betwee n groups when local anesthetic without epinephrine was used. Clinical Implications. Use of local anesthetic containing a vasoconstrictor should be avoided in patients taking beta-blocker medication because of a possible adverse drug interaction. However, when a vasoconstrictor is indic ated for hemostasis, the local anesthetic should be administered slowly and in small amounts as pulse rate and blood pressure are being monitored. The patient should be informed that the duration of anesthesia might be prolon ged.