Vitamin-C

# Vitamin-C ## Overview - **Classification**: Water-soluble vitamin, Antioxidant. - **Mechanism**: Essential cofactor in collagen synthesis, carnitine, and neurotransmitter production. Acts as an antioxidant, protecting against oxidative stress. Enhances non-heme iron absorption. ## Primary Indications 1. **Scurvy Treatment** - Reversal of clinical signs of Vitamin C deficiency. 2. **Scurvy Prevention** - Dietary supplementation in at-risk populations. 3. **Vitamin C Deficiency** - Supplementation in conditions causing inadequate intake or malabsorption. ## Adult Dosing ### Standard Dosing **Scurvy Treatment** - **Dose**: **100-250 mg** - **Frequency**: **1-2 times daily** - **Route**: Oral, IM, IV, SubQ - **Duration**: At least **2 weeks** or until clinical signs resolve. **Scurvy Prevention (RDA)** - **Dose**: **65-90 mg** (non-smokers); **>125 mg** (smokers) - **Frequency**: **Once daily** - **Route**: Oral - **Maximum**: **2000 mg/day** (Upper Limit, UL) ### Dose Adjustments - **Renal Impairment**: No specific adjustment needed for low doses. High doses (**>1 g/day**) may increase risk of oxalate nephropathy, especially in ESRD. - **Hepatic Impairment**: No specific adjustment needed. - **Elderly Patients**: No specific adjustment. Consider malabsorption or poor dietary intake. ## Pediatric Dosing ### Neonates (0-28 days) - **Indication**: Scurvy treatment/prevention of deficiency - **Dose**: **50-100 mg** - **Frequency**: **Once daily** - **Route**: Oral (liquid), IM, IV - **Maximum**: **100 mg/day** - **Special Notes**: Use age-appropriate liquid formulations. ### Infants (1-12 months) - **Indication**: Scurvy treatment/deficiency - **Dose**: **50-100 mg** - **Frequency**: **Once daily** - **Route**: Oral (liquid), IM, IV - **Maximum**: **400 mg/day** (Upper Limit, UL, for 7-12 mos) ### Children (1-12 years) - **Indication**: Scurvy treatment/deficiency - **Dose**: **100-300 mg** - **Frequency**: **Once daily** - **Route**: Oral, IM, IV - **Maximum**: **400 mg/day** (UL, 1-3 years); **650 mg/day** (UL, 4-8 years); **1200 mg/day** (UL, 9-13 years) ### Adolescents (13-18 years) - **Indication**: Scurvy treatment/deficiency - **Dose**: **100-300 mg** - **Frequency**: **Once daily** - **Route**: Oral, IM, IV - **Maximum**: **1800 mg/day** (Upper Limit, UL) ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to ascorbic acid. - **Relative**: History of oxalate nephrolithiasis (high doses). - **Relative**: Hemochromatosis, G6PD deficiency (caution with high doses, especially IV). ### Common Adverse Effects - **Very Common (>10%)**: Generally well-tolerated at recommended doses. - **Common (1-10%)**: Nausea, vomiting, diarrhea, abdominal cramps (with high oral doses). - **Serious but Rare**: Hyperoxaluria, kidney stone formation (prolonged high doses). Hemolysis in G6PD deficiency (high IV doses). ### Key Drug Interactions - **Deferoxamine**: Concurrent use may increase iron-induced cardiac toxicity. Separate administration by several hours. - **Warfarin**: High doses of Vitamin C (**>1g/day**) may theoretically decrease anticoagulant effect. Monitor INR. - **Aluminum-containing Antacids**: Vitamin C can increase aluminum absorption. Avoid large doses concurrently. - **Chemotherapy**: Theoretical concern of interfering with chemotherapy efficacy due to antioxidant properties. Discuss with oncologist. ## Monitoring & Follow-up - **Before Treatment**: Assess dietary intake, consider other nutritional deficiencies. - **During Treatment**: Monitor for resolution of clinical signs of scurvy (e.g., gingival bleeding, petechiae, fatigue). - **Clinical Signs**: Observe for improved gum health, reduced bruising, increased energy. ## Clinical Pearls - 💡 **Tip 1**: Administer oral doses with food to minimize potential gastrointestinal upset. - 💡 **Tip 2**: High doses of Vitamin C can interfere with certain laboratory tests (e.g., urine glucose, fecal occult blood). - 💡 **Tip 3**: Smoking significantly increases Vitamin C requirements due to increased oxidative stress. - 💡 **Tip 4**: Urine may appear yellowish with high doses, which is typically harmless. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.