Metformin attenuates the postprandial fall in blood pressure in type 2 diabetes

Abstract

Metformin has been shown to modulate the cardiovascular response to intraduodenal glucose in patients with type 2 diabetes (T2DM), and may have the capacity to regulate postprandial blood pressure (BP), which is often inadequately compensated in T2DM, resulting in postprandial hypotension. In the present study, we evaluated the acute effects of metformin on the BP and heart rate (HR) responses to oral glucose in patients with T2DM. Ten diet‐controlled T2DM patients were evaluated on two occasions in a double‐blind, randomized, crossover design. Participants received either metformin 1\u2009g or saline (control) intraduodenally 60\u2009minutes before ingesting a 50\u2009g glucose drink labelled with 150\u2009mg 13C‐acetate. BP, HR, plasma glucagon‐like peptide‐1 (GLP‐1) and gastric emptying (breath test) were evaluated over 180\u2009minutes. Systolic and diastolic BP decreased and HR increased after oral glucose (P\u2009<\u20090.001 for all) on both days. Metformin attenuated the fall in systolic BP (P\u2009<\u20090.001), increased plasma GLP‐1 concentrations (P\u2009<\u20090.05) and slowed gastric emptying (P\u2009<\u20090.05) without significantly affecting diastolic BP or HR. In conclusion, metformin acutely attenuates the hypotensive response to oral glucose, associated with augmented GLP‐1 secretion and delayed gastric emptying, effects potentially relevant to its favourable cardiovascular profile.