Rationale for the Assessment of Metoprolol in the Prevention of Vasovagal Syncope in Aging Subjects Trial (POST5)

POST5 Investigators

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Background Vasovagal syncope (VVS) is a common problem associated with a poor quality of life, which improves when syncope frequency is reduced. Effective pharmacological therapies for VVS are lacking. Metoprolol is a β-adrenergic receptor antagonist that is ineffective in younger patients, but may benefit older (≥40 years) VVS patients. Given the limited therapeutic options, a placebo-controlled clinical trial of metoprolol for the prevention of VVS in older patients is needed. Structure of study The POST5 is a multicenter, international, randomized, placebo-controlled study of metoprolol in the prevention of VVS in patients ≥40 years old. The primary endpoint is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive metoprolol 25 to 100 mg BID or matching placebo, and followed up for 1 year. Secondary end points include syncope frequency, presyncope, quality of life, and cost analysis. Primary analysis will be intention to treat, with a secondary on-treatment analysis. Power calculations A sample size of 222, split equally between the groups achieves 85% power to detect a hazard rate of 0.3561 when the event rates are 50% and 30% in the placebo and metoprolol arms. Allowing for 10% dropout, we propose to enroll 248 patients. Implications This study will be the first adequately powered trial to determine whether metoprolol is effective in preventing VVS in patients ≥40 years. If effective, metoprolol may become the first line pharmacological therapy for these patients.

Original languageEnglish (US)
Pages (from-to)89-94
Number of pages6
JournalAmerican Heart Journal
StatePublished - 2016

Bibliographical note

Funding Information:
This study is supported by a grant, MOP-299689, from the Canadian Institutes of Health Research, Ottawa, Canada, to RSS. Apotex Pharmaceuticals (Toronto, Ontario, Canada) is providing the placebo capsules.

Funding Information:
This study is funded by the Canadian Institutes of Health Research (CIHR; Ottawa, Canada) operating grant #MOP-299689. Study drug has been purchased from Apotex, Inc (Toronto, Ontario, Canada). Apotex, Inc, created and provided matching placebo tablets. The authors are solely responsible for the design and conduct of the study, all study analyses, the drafting and editing of the manuscript, and its final contents.

Publisher Copyright:
© 2016 Elsevier Inc. All rights reserved.


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