Vitamin C2026-07

High-Dose Intravenous Vitamin C in Critical Illness: A Translational Exposure-Response Framework for Biomarker-Guided Precision Therapy.

Bajić Dejana, Andrijević Ljiljana, Todorović Nemanja, Lalić-Popović Mladena et al. — Medical sciences (Basel, Switzerland)

Summary

This paper explores how high doses of vitamin C given directly into the bloodstream might help critically ill patients, like those with severe infections or lung conditions. Unlike the vitamin C we get from food, these very high doses act more like a drug, influencing body processes such as inflammation. The research suggests that for it to be effective, the right dose, timing, and patient selection are crucial, potentially guided by specific biological markers.

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Key points

High doses of vitamin C given intravenously are being studied for critically ill patients, acting more like a medicine than a nutrient.
Its effectiveness may depend on factors like the specific dose, when it's given, and individual patient responses.
Future treatment strategies might use biological markers to personalize vitamin C therapy for critical illnesses.
This research focuses on medical interventions, not on daily dietary vitamin C intake.

What the study looked at

What question the study asked: This paper explored why high-dose intravenous vitamin C, despite promising lab results, has shown inconsistent outcomes in clinical trials for critically ill patients like those with sepsis or severe respiratory conditions. It aimed to understand how factors like the amount of vitamin C in the body, when it's given, and individual patient differences might explain these varied results. How it was studied (design/participants): This was a review paper, meaning the authors synthesized existing clinical and scientific evidence. They developed a conceptual framework to link the amount of vitamin C a patient is exposed to (pharmacokinetics) with the body's response (pharmacodynamics), considering its role as a pharmacological agent rather than just a nutrient in critical illness. What it found: The review suggests that very high doses of vitamin C, achievable only through intravenous administration, can reach levels where it acts like a drug, affecting processes like inflammation and blood vessel function. The inconsistent trial results might be due to variations in how much vitamin C reaches the tissues, the timing of administration relative to disease progression, and individual patient factors. The paper proposes using biological markers (like inflammation indicators) to guide personalized, "precision" vitamin C therapy in the future, ensuring the right dose is given at the right time to the right patient.

Dietary takeaway

This research focuses on very high, medically administered doses of vitamin C for critically ill patients, which is different from the vitamin C we get from food. For general health, it's still important to consume a variety of fruits and vegetables daily to meet your vitamin C needs. Remember, this specific study explores a specialized medical treatment, and its findings don't directly apply to typical dietary choices for healthy individuals.

Abstract

High-dose intravenous vitamin C (HDIVC) has been investigated as a potential adjunctive therapy in critical illness, including sepsis, acute respiratory distress syndrome (ARDS), and COVID-19. Despite a strong mechanistic rationale, clinical trials have yielded inconsistent results. From a clinical pharmacology perspective, this variability may reflect, at least in part, differences in pharmacokinetic exposure, timing of administration, and patient selection rather than a lack of biological activity. Intravenous administration enables plasma concentrations in the millimolar range (≈1-5 mM), far exceeding those achievable with oral dosing (<100 µM), thereby reaching thresholds required for pharmacodynamic effects on oxidative stress, immune signaling, and endothelial function. This exposure-dependent transition distinguishes vitamin C as a pharmacological agent rather than a nutritional supplement in critically ill populations. Therapeutic response may be influenced by timing relative to disease progression, with earlier administration representing a biologically plausible strategy that warrants prospective evaluation rather than a clinically established therapeutic window. Interindividual variability in transporter function, redox status, and genetic background may further contribute to heterogeneous responses. Biomarkers such as interleukin-6 (IL-6), C-reactive protein (CRP), D-dimer, and markers of endothelial injury provide a framework for patient stratification and monitoring of pharmacodynamic effects. Integrated with pharmacokinetic principles, these markers support a shift toward biomarker-guided, precision-based therapeutic strategies. This review synthesizes current clinical and mechanistic evidence through an exposure-response conceptual framework, framing HDIVC as a context-dependent pharmacological intervention and advancing a shift toward biomarker-guided, precision-based therapeutic strategies in critical illness.

View on PubMed →DOI: 10.3390/medsci14030400