Clinical Trial: Blood Pressure Interaction Between Sildenafil and Sublingual Glyceryl Trinitrate (GTN) in Men With Angina

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Investigation of the Time Course of the Interaction of the Hypotensive Effects of Sildenafil Citrate and Sublingual Glyceryl Trinitrate (GTN) in Men With Stable Angina Pectoris

Brief Summary: The purpose of the study is to determine for how long sildenafil potentiates the blood pressure reduction that occurs with glyceryl trinitrate in men with angina.

Detailed Summary:

By producing a mediator known as cGMP, nitric oxide (NO) potently dilates blood vessels. Nitrates, such as glyceryl trinitrate (GTN), are drugs that release NO (NO donors) and are widely used in the treatment and prevention of angina. Sildenafil is an effective treatment for male penile erectile dysfunction that inhibits the breakdown cGMP. When given alone it causes modest reductions in BP in healthy people and patients with cardiovascular disease. By their synergistic actions, co-administration of NO donors with sildenafil can result in large reductions in BP in patients with angina, a population at increased risk of developing erectile dysfunction. As a result, it is recommended that the two drugs not be co-administered within 24 hours of one another.

Previous studies have defined the effect of nitrates at 60 min after administration of sildenafil, the time of likely maximum interaction. However, emergency medicine physicians would value evidence of a balance of risks from which to make a personal clinical judgement about when they might consider giving GTN in a patient presenting with a severe episode of angina who has recently received sildenafil. Evidence on which to base such a judgement is currently not available. However, we have recently completed a study, showing that the interaction of GTN (0.4 mg spray) after sildenafil (100 mg) lasts less than 4 hours in healthy subjects. Whilst the findings would probably be similar for patients with angina, this question now needs to be investigated directly in order to ensure the generalisability of this work and address an important unresolved clinical issue.

Subjects will be asked to refrain from using short-acting nitrates for 24 hours and long acting nitrates for 72 hours before the start of the study. On the morning of each study visit subjects will take their normal
Sponsor: University of Edinburgh

Current Primary Outcome: Effect of combined sildenafil and GTN on mean maximum reduction in blood pressure

Original Primary Outcome: Same as current

Current Secondary Outcome:

Original Secondary Outcome:

Information By: University of Edinburgh

Dates:
Date Received: May 29, 2007
Date Started: January 2004
Date Completion:
Last Updated: May 29, 2007
Last Verified: May 2007