Medication that lowers blood pressure is equally effective if taken in the morning or evening, a large clinical trial has found.

This overturns previous research that suggested blood pressure-lowering medication may be more effective if taken in the evening.

Blood pressure-lowering medications are among the most widely prescribed in the U.K., with between seven and nine million people taking them to reduce their risk of developing heart and circulatory diseases.

Clinical trial

This new randomized-controlled trial of more than 21,000 patients with high blood pressure found that protection against heart attack, stroke or circulatory diseases is not affected by whether blood pressure drugs are taken in the morning or evening.

Participants in the trial were taking at least one medication to lower their blood pressure. Half were asked to take their medication in the evening and the other half were asked to take it in the morning.

After following those on trial for five years, it was found that there was no difference in the number of people who had a heart attack, stroke or circulatory disease—362 in the morning group versus 390 in the evening.

The research was carried out by teams from Universities of Edinburgh, Dundee, Glasgow and Oxford, Imperial College London, and Queen Mary University of London.

The study has been published in The Lancet.

"The main message from the study is that there is no optimal time to take blood pressure tablets to achieve a better outcome, so patients should take their tablets at the time that suits them best," says Professor David Webb, Christison Chair of Therapeutics and Clinical Pharmacology and author on the study.