The effect of clonidine

Abstract

The effect of clonidine, a central alpha2-adrenoreceptor agonist on reduction of anxiety, producing sedation and attenuation hemodynamic changes, were assessed during thissemi-experimental study in one of the hospitals of Iran medical sciences university in Tehran, 1994. Fifty surgical patients of either sex, 18-60 years of age, with ASA physical status I or II, gave informed consent to enter this study. At the preoperative visit on the evening before surgery, arterial blood pressure and heart rate were recorded and patient's anxiety were assessed by a scale (check list). Then patients were randomly assigned to either a clonidine (No=25) or control (No =25) group. In the study group, each patient received one tablet of clonidine (0.2 mg) 2-3 hours prior to coming to the operating room, and patients in control group, did not receive any medication. On the patient's arrival in the operating room, the degree of sedation was assessed by researcher on a three point scale: awake and allert -drowsy but communicative -drowsy, uncommunicative. A second scale for anxiety was completed and heart rate and arterial blood pressure were recorded again anesthesia was induced intravenously with 3-5 mg/kg of tiopental-Na and 1.5 mg/kg succynil cholin to facilitate the laryngoscopy and tracheal intubation. Heart rate and arterial blood pressure were recoreded just before induction of anesthesia and one minute after tracheal intubation. Results of this study are presented in 25 tables, and statistical analysis done by T -test, paired T-test and chi-square, statistical significance was accepted at P<0.05. Results: There were no significant differences in patients' demographic characteristics and preoperative anxiety, heart rate and arterial blood pressure between the clonidine and control group. Pre-induction anxiety was significantly less in the clonidine group compared with control group (P<0.001) and pre-induction sedation was significantly more in the clonidine group compared with control group (P<0.05). Although preoperative cardiovascular readings were similar in both group, compared with baseline values, the changes of systolic blood pressure, diastolic blood pressure and heart rate were significantly less in the clonidine group after arrival to operation room and one minute after tracheal intubation compared with the control group (P<0.05). Thus, the hypothesis (oral clonidine as a premedicant drug, can affect the anxiety, sedation and hemodynamic changes, in the patients undergoing surgery with general anesthesia), is protected by results. Further recommendation for future studies are presented.