Chronopharmacology in Hypertension

Abstract

The blood pressure (BP) of both normotensive and hypertensive patients has a particular pattern associated with the body's inherent clock set according to a circadian rhythm, thus the timing of antihypertensive drug administration is important. This study compared the effects of morning and evening dosing of the antihypertensive drugs atenolol and perindopril on both circadian BP and heart rate (HR) in essential hypertensive patients as a whole group and between gender.

Patients on once daily perindopril (4 females, 8 males; age 55 ± 13.1 years dose 4-8mg/day) (mean ± S.D.) and once daily atenolol (4 females, 5 males; age 49.9 ± 11.2 years; dose 50-100mg/day) participated in the study. The patients suffered from essential hypertension, were on no other antihypertensive medications or medications that affect BP. Each patient was instructed to take the antihypertensive drug in the morning at 0800h for five days, and then cross over to evening administration (2000h) for another five days. The BP and HR were monitored for 24 hours after each treatment period using an ambulatory blood pressure monitor (ABPM). This study took place at the Medical Out-Patients at St Luke's Hospital (SLH), Mosta Health Centre and Cardiac Laboratory (SLH), using the ABPM (A&D TM-2340 and Schiller BR-102 models) to monitor daily systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR values.

Evening administration of atenolol reduced HR significantly during early morning period (0600h-1000h) when compared to morning atenolol administration and evening perindopril administration (p
Atenolol administered in the evening produced a significantly lower HR during the early morning period, which may be advantageous in reducing early morning cardiovascular risk. Difference in sex affects the efficacy of antihypertensive agents.

Date of Award	3 Dec 2007
Original language	English
Supervisor	Anthony Serracino-Inglott (Promotor) & Louise Azzopardi (Co-promotor)