Adverse cardiovascular responses to thyrotropin-releasing hormone (200 micrograms) in cardiac patients

Although a pressor effect of 500 micrograms i.v. thyrotropin-releasing hormone (TRH) in noncardiac patients has been reported, the effect of a lesser dose of TRH (200 micrograms) in cardiac patients has not been evaluated. We performed a 200 micrograms i.v. TRH test to exclude thyrotoxicosis in 20 cardiac patients, aged 38 to 42 years. No clinical side effects were noted, but increments in systolic and diastolic blood pressure of 21.8 +/- 2.7 and 17.3 +/- 1.6 mm Hg (SE), respectively, were documented. Mean arterial pressure rose from 104.9 +/- 2.9 to 123.7 +/- 5.5 mm Hg (SE) after TRH (P less than 0.001). In nine patients the pressor response persisted for 5 to 20 min, and blood pressures of 220 mm Hg systolic and 145 mm Hg diastolic were recorded. We conclude that the 200 micrograms TRH i.v. has a significant pressor effect.