Effects of magnesium on blood pressure and intracellular ion levels of Brazilian hypertensive patients

• Published in: International journal of cardiology Vol. 56; no. 2; pp. 177 - 183
• Main Authors: Sanjuliani, Antonio Felipe, de Abreu Fagundes, Virginia Genelhu, Francischetti, Emílio Antonio
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 11.10.1996; Elsevier Science
• Subjects: Administration, Oral; Adult; Aged; Aldosterone - blood; Antihypertensive Agents - administration & dosage; Antihypertensive Agents - pharmacokinetics; Antihypertensive Agents - therapeutic use; Biological and medical sciences; Blood pressure; Blood Pressure - drug effects; Brazil; Calcium - pharmacokinetics; Cardiovascular system; Cross-Over Studies; Double-Blind Method; Erythrocytes - drug effects; Erythrocytes - metabolism; Female; Humans; Hypertension; Hypertension - drug therapy; Intraerythrocyte magnesium; Intraerythrocyte sodium; Magnesium; Magnesium - administration & dosage; Magnesium - pharmacokinetics; Magnesium - therapeutic use; Magnesium Oxide - administration & dosage; Magnesium Oxide - pharmacokinetics; Magnesium Oxide - therapeutic use; Male; Medical sciences; Middle Aged; Miscellaneous; Pharmacology. Drug treatments; Placebos; Potassium - pharmacokinetics; Renin - blood; Sodium - pharmacokinetics; Sodium - urine; Brazil; Hypertension; Blood pressure; Magnesium; Intraerythrocyte magnesium; Intraerythrocyte sodium; Human; Chemotherapy; Treatment; Treatment efficiency; Oral administration; Cardiovascular disease; Exploration; Ions; Arterial pressure; Intracellular
• ISSN: 0167-5273; 1874-1754
• DOI: 10.1016/0167-5273(96)02716-7

Fifteen patients with uncomplicated mild to moderate primary hypertension (7 males, 8 females, age range 36–65 years) were submitted to a double blind randomized crossover study, receiving MgO 3 times a day at a daily dose of 1.0 g (600 mg/day of magnesium) and placebo for a period of 6 weeks. This was to test the effects of oral magnesium supplementation on blood pressure and sodium, potassium, calcium and magnesium intraerythrocyte concentrations. Concomitantly, plasma renin activity and serum aldosterone was also measured. Oral magnesium reduced significantly the systolic (Δ = −7.6 mmHg, P < 0.05); diastolic (Δ = −3.8 mmHg, P < 0.01) and mean blood pressure (Δ = −5.9 mmHg, P < 0.01). After magnesium supplementation intraerythrocyte sodium concentration was reduced (Δ = −0.55 mEq/l per cell, P < 0.01) and intraerythrocyte magnesium concentration was increased (Δ = 1.20 mg/dl per cell, P < 0.01). The diminution of the blood pressure correlated positively with the reduction in intraerythrocyte sodium ( r = 0.66, P < 0.01) after magnesium. However, our results have shown that the blood pressure response to oral magnesium was not homogeneous. Forty percent of our patients had their blood pressure effectively controlled (more than 10 mmHg reduction in mean blood pressure), being the hypotensive effect more evident in patients with recent hypertension and in those where the reduction in intraerythrocyte sodium was significantly greater than in the non-responder individuals. Intraerythrocyte potassium and calcium, serum aldosterone, plasma renin activity and urinary sodium excretion were maintained unchanged after magnesium supplementation. These data showed that oral magnesium supplementation may reduce the blood pressure, which can be partially explained by the decrease in intracellular sodium and augment in intracellular magnesium.