Is It Safe to Use Vasoconstrictors in Association Treated with Amitriptyline or Can It Potentiate Cardiovascular Effects? In Vivo Animal Study

This study aimed to evaluate changes in blood pressure of rats treated or not with amitriptyline after infiltration in the buccal sulcus and intravenous injection of epinephrine, felypressin and phenylephrine in equivalent doses (ED) to the amounts present in 2, 8 and 32 local anesthetic tubes. 42 male Wistar rats, with 45-day-old, treated for seven days with amitriptyline hydrochloride (0.3 mg/kg). On the eighth day, the animal was submitted to general anesthesia and surgery for direct blood pressure rate. The significance level was 5%. The treatment with amitriptyline caused a significant decrease in blood pressure of the treated group compared to the control group (101.80 ± 2.52 and 110.12 ± 2.91 mmHg, respectively, * p < 0.05), and slightly potentiates the hypertensive response after infiltration of epinephrine (4.11 ± 0.54; 7.15 ± 0.55; 9.03 ± 0.87 mmHg, respectively, 2, 8 and 32 tubes, p > 0.05). Felypressin promotes lower blood pressure changes and phenylephrine proved to be the most potent vasoconstrictor of the three studied, producing important changes in blood pressure and, even though infiltration, in doses greater than 8 tubes (15.43 ± 1.15; 70.62 ± 3.70 mmHg, respectively, 8 and 32 tubes, * p < 0.05). The infiltration of the three vasoconstrictors in doses equal to or less than 8 tubes does not cause significant changes in blood pressure, both in the control and amitriptyline treated groups.