Does metformin increase blood pressure
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The Impact of Metformin on Blood Pressure: A Comprehensive Review
Introduction to Metformin and Blood Pressure
Metformin is a widely used medication primarily prescribed for managing type 2 diabetes. Its effects on blood pressure (BP) have been a subject of interest due to its potential cardiovascular benefits. This article synthesizes findings from multiple studies to determine whether metformin increases blood pressure.
Metformin and Blood Pressure in Hypertensive, Obese Women
A study focusing on nondiabetic, obese, hypertensive women found that metformin significantly reduced both systolic and diastolic blood pressure. The study involved 12 women who received 850 mg of metformin twice daily for 12 weeks. The results showed a notable decrease in blood pressure, along with improvements in glucose metabolism and lipid profiles.
Metformin's Effect on Blood Pressure in Type 2 Diabetes
In a study comparing the effects of vildagliptin and metformin on blood pressure in patients with type 2 diabetes, it was found that metformin did not significantly affect systolic or diastolic blood pressure. However, it did increase heart rate during glucose infusion. This suggests that while metformin may not directly influence blood pressure in diabetic patients, it can affect other cardiovascular parameters.
Meta-Analysis of Metformin's Impact on Blood Pressure
A comprehensive meta-analysis of randomized controlled trials evaluated the effects of metformin on blood pressure in nondiabetic patients. The analysis included 28 studies with a total of 4113 participants. The findings indicated that metformin significantly reduced systolic blood pressure by an average of 1.98 mmHg but had no significant effect on diastolic blood pressure. This reduction was more pronounced in patients with impaired glucose tolerance or obesity.
Clinical Trials on Metformin and Hypertension
Several clinical trials have investigated metformin's role in managing hypertension. One such trial involving 97 hypertensive patients without diabetes found no significant difference in blood pressure reduction between the metformin and placebo groups after 8 weeks of treatment. Another study with a similar design also reported no significant changes in 24-hour ambulatory blood pressure measurements.
Orthostatic Blood Pressure and Metformin
A study from the Copenhagen Insulin and Metformin Therapy (CIMT) trial examined the effects of metformin on orthostatic blood pressure recovery in patients with type 2 diabetes. The results indicated that metformin increased the early drop in orthostatic blood pressure, suggesting a potential adverse effect on cardiovascular autonomic function.
Blood Pressure in Offspring of Women Treated with Metformin
Research from the MiG trial assessed blood pressure in children born to women who were treated with metformin for gestational diabetes. The study found no significant differences in systolic or diastolic blood pressure between the metformin and insulin treatment groups at two years of age.
Systematic Reviews and Meta-Analyses
Systematic reviews and meta-analyses have provided mixed results regarding metformin's impact on blood pressure. One review concluded that metformin does not have a significant intrinsic effect on blood pressure in patients with type 2 diabetes, although it does improve lipid profiles . Another review highlighted that metformin might improve insulin sensitivity and reduce blood pressure in non-diabetic hypertensive patients.
Conclusion
The evidence suggests that metformin does not increase blood pressure. In fact, it may slightly reduce systolic blood pressure, particularly in nondiabetic, obese, or glucose-intolerant individuals. However, its effects on diastolic blood pressure and heart rate are less clear, and it may have adverse effects on orthostatic blood pressure recovery. Overall, metformin appears to have a neutral to mildly beneficial impact on blood pressure, contributing to its favorable cardiovascular risk profile.
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