Hyper-glycaemic effect of calcium channel blockers
Dr. Seema Mishra
New CCBs that inhibit calcium channel subtypes have been developed over the past decade. Treatment of hypertension has been carried out not only using long-acting CCBs but also other CCBs selected on the basis of the characteristics of the calcium channel subtype they block. It is well known that amlodipine acts on L-type calcium channels abundantly expressed on vascular smooth muscle, and cilnidipine acts on N-type calcium channels that abound in the sympathetic nervous system as well as on L-type calcium channels. Therefore, we compared the efficacy of amlodipine with that of cilnidipine using a cross-over study design in hypertensive patients. The two drugs were administered to all patients, irrespective of the presence/absence of diabetes mellitus. Attempts were made to reduce the blood pressure of each patient to the goal of blood pressure control, without modifying the dose of concomitantly used antihypertensive drugs such as beta-blockers. Among the patients in whom the goal blood pressure was attained, the heart rate with cilnidipine did not differ significantly from that with amlodipine. Hoshide et al. reported that in a study using amlodipine elevated daytime and nocturnal heart rate, while cilnidipine reduced daytime and nocturnal heart rate. Therefore, the heart rate data collected from the patients of this study have reflected adequately the inhibitory effects of cilnidipine on N-type calcium channels.