The acute effect of high-dose intravenous vitamin C and other nutrients on blood pressure: a cohort study

BACKGROUND Regular intake of vitamin C/ascorbate reduces blood pressure (BP) in hypertensives. High-dose intravenous vitamin C (IVC) achieves higher plasma levels; however, there is a paucity of research on acute BP effects. Our study is the first to investigate the effect of high-dose IVC, with or without concomitant i.v. nutrients, on BP during i.v. METHODS A cohort of adult patients scheduled to receive IVC treatment for infection, cancer or fatigue, as prescribed by their treating doctor, participated at a Melbourne clinic, Australia. Ambulatory BP was assessed every 10 min over 90 min during i.v. TREATMENT Patients received 15-100 g of IVC alone or in addition to i.v. vitamin B, glutathione, magnesium or zinc. BP change over time adjusted for baseline BP, IVC dosage, i.v. treatment and BMI was analysed. RESULTS A total of 77 mostly normotensive patients participated, with a third receiving IVC alone (42±20 g), and two-thirds also received other i.v. nutrients. IVC alone (>30 g) reduced the mean BP up to 8-9 mmHg in prehypertensive patients. In contrast, concomitant intravenous vitamin B12 (IVB12) significantly increased the mean BP by 11-13 mmHg. Comparison of BP change during IVC versus IVC+IVB12 indicated a highly significant difference [systolic blood pressure: mean difference (SD)=16.6 (17.8) mmHg, P<0.001; diastolic blood pressure: mean difference (SD)=12.5 (16.7) mmHg, P=0.003]. CONCLUSION Our study suggests an acute BP-reducing effect of high-dose IVC, particularly with dosages above 30 g, and in patients with prehypertension and normal BMI. Furthermore, our study indicated a marked and clinically relevant hypertensive effect of IVB12, suggesting routine BP monitoring during i.v. therapy in clinical practice.