From the FDA Drug Label
DOSAGE AND ADMINISTRATION Administer intramuscularly 1 to 10 mL, depending on condition, species, and body weight. Repeat daily or as indicated by desired response. The dose of intramuscular vitamin C to give is 1 to 10 mL, depending on the condition, species, and body weight of the patient, as indicated by the desired response 1.
- The dose should be administered intramuscularly.
- The dose may be repeated daily or as indicated by the desired response.
From the Research
The recommended intramuscular vitamin C dosage is 1-2 grams per day for adults, administered as a deep intramuscular injection, as higher doses may be necessary for severe deficiency or therapeutic purposes, as suggested by the most recent study 2. When administering intramuscular vitamin C, it is essential to consider the patient's individual needs and medical history. The injection should be given slowly into a large muscle, such as the gluteal muscle (buttock) or vastus lateralis (thigh). Some key points to consider when administering intramuscular vitamin C include:
- The solution should be clear and colorless; discard if discolored or contains particles.
- Side effects may include pain at injection site, dizziness, or flushing.
- Vitamin C is water-soluble, so excess amounts are generally excreted through urine, but high parenteral doses can cause oxalate crystal formation in some patients.
- Always use aseptic technique when administering intramuscular injections and monitor for any adverse reactions. The most recent study 2 suggests that pharmacological doses of vitamin C (6-16 g/day) may be beneficial in reducing vasopressor support and organ dysfunction in critically ill patients. However, it is crucial to note that large randomized controlled trials are necessary to provide more evidence before wide-scale implementation can be recommended. In terms of specific dosing, the study 2 mentions that older studies showed less organ dysfunction when vitamin C was administered in repletion dose (2-3 g intravenous vitamin C/day). It is also important to consider the findings of other studies, such as 3, which highlights the importance of route of administration, with intravenous administration producing higher plasma and urine concentrations of vitamin C compared to oral administration. However, the most recent and highest quality study 2 takes precedence in guiding clinical decision-making.