Sedative and cardiovascular effects of midazolam and diazepam alone or combined with clonidine in patients undergoing hemodynamic studies for suspected coronary artery disease.

Background: Sedation during coronary angiography has been rarely studied, and it is important to know which drug is the best to sedate these patients.

Objective: To evaluate the quality of sedation and the effects of midazolam and diazepam alone or combined with clonidine on the heart rate (HR) and blood pressure (BP) of patients with suspected coronary artery disease.

Methods: This is a controlled, randomized, double-blind, prospective clinical study of 160 patients divided into five groups of 32 patients each, according to the drug used: group C (clonidine 0.5 microg/kg); group M (midazolam 40 microg/kg); group MC (combination of midazolam 40 microg/kg and clonidine 0.5 microg/kg); group D (diazepam 40 microg/kg); and group DC (combination of diazepam 40 microg/kg and clonidine 0.5 microg/kg). Sedation was evaluated based on the Ramsay scale and on the use of meperidine 0.04 mg.kg-1. Invasive BP monitoring, HR and the sedation score were analyzed every five minutes at four different time points.

Results: Patients who received midazolam presented higher sedation scores as well as HR and BP variation (p < 0.05). Those who received diazepam or clonidine had lower sedation scores, which were more satisfactory for the performance of the procedure, and presented a lower BP and HR variation (p > 0.05).

Conclusion: Midazolam was associated with a greater sedative and cardiovascular effect, whereas for diazepam these effects were less intense. Clonidine and diazepam had similar effects on BP, HR and sedation.