Hypersensitivity. Hemochromatosis, hemosiderosis & non-iron deficiency anemia. History of nephrolithiasis, hyperoxaluria, oxalate dysbolism & thalassemia. Avoid large doses of vit C (>1 g/day). G6PD deficiency. Infants <12 mth.
Transient constipation, diarrhea, nausea, vomiting, dark stools, bellyache. High doses of vit C may cause hyperoxaluria, nausea, vomiting, heartburn, abdominal cramps, fatigue, flushing, headache, insomnia, sleepiness; diarrhea.
Risk of hyperkalemia w/ antialdosterone agent or triamterene. Avoid use w/ phosphates, Ca salts, oral tetracyclines, antacids, levodopa. Decreased Fe absorption w/ tannin-containing products (eg green tea, red tea).