Effect of nifedipine on cardiovascular responses to laryngoscopy and intubation.

The efficacy of sublingual nifedipine in attenuating the pressor responses to laryngoscopy and intubation was studied in 40 patients undergoing elective surgery. Anaesthesia was induced with thiopentone 5.5 mg kg-1 i.v. and tracheal intubation was facilitated with suxamethonium 1.5 mg kg-1 i.v. Patients were allocated randomly to receive sublingual nifedipine 10 mg or placebo capsules 10 min before induction. Patients receiving placebo capsule showed significant increases in heart rate and arterial pressure associated with tracheal intubation (P less than 0.001). The increases in arterial pressure and rate-pressure product were reduced in nifedipine treated patients (P less than 0.001). Heart rate increased significantly in both groups immediately after intubation.