Vitamin C (Ascorbic Acid) is a water-soluble vitamin essential for collagen synthesis, antioxidant defense, and immune function. In the Indian context, a 75mg dose is commonly used for daily nutritional supplementation, prophylaxis, and as adjunctive therapy in conditions with increased oxidative stress or mild deficiency. It is a critical cofactor for enzymes involved in neurotransmitter synthesis, carnitine production, and iron absorption.
Adult: Prophylactic: 75-100mg orally once daily. Therapeutic (for deficiency): 250-500mg daily in divided doses for at least 2 weeks, then maintenance dose.
Note: Administer orally, preferably with or after meals to reduce gastrointestinal irritation. Tablet/Capsule should be swallowed whole with a glass of water. Chewable or dispersible forms are available. Avoid taking close to antacids containing aluminum (may increase aluminum absorption).
Vitamin C acts as an essential cofactor for multiple enzymatic reactions, primarily those involving hydroxylation. It is a potent water-soluble antioxidant that scavenges reactive oxygen and nitrogen species, thereby protecting cellular components from oxidative damage. It also regenerates other antioxidants like Vitamin E.
Pregnancy: Category A (when used in recommended daily allowances). 75mg/day is safe and often included in prenatal supplements. RDA in pregnancy is 85mg. High doses (>UL) should be avoided.
Driving: No effect on ability to drive or operate machinery.
| Oral Iron Supplements (Ferrous sulfate/fumarate) | Vitamin C enhances the absorption of non-heme iron, increasing its bioavailability by 2-3 times. | Moderate |
| Aspirin and NSAIDs | May decrease Vitamin C renal tubular reabsorption, increasing its excretion and potentially lowering body stores. | Mild |
| Oral Contraceptives (Estrogen) | Estrogen may increase Vitamin C requirements and decrease plasma ascorbate levels. | Mild |
| Warfarin | Theoretical interaction; high-dose Vitamin C may slightly reduce anticoagulant effect, but not clinically significant at 75mg. | Minor |
| Aluminum-containing Antacids | Vitamin C may increase aluminum absorption, potentially leading to toxicity in renal impairment. | Moderate (in renal disease) |
| Chemotherapy (e.g., Bortezomib, Doxorubicin) | Antioxidants may theoretically interfere with the oxidative mechanism of some chemotherapeutic agents. Consult oncologist. | Major |