250 mg or 500 mg tablet (Rocal Or): Used for treatment or prevention of calcium depletion when diet is inadequate. Associated conditions: hypoparathyroidism, achlorhydria, chronic diarrhea, vitamin D deficiency, steatorrhea, sprue, pregnancy, lactation, menopause, pancreatitis, renal failure, alkalosis, hyperphosphatemia. Commonly used in chronic renal failure and dialysis patients for hyperphosphatemia. Provides short‑term relief of dyspeptic symptoms but not recommended for long‑term peptic ulcer treatment.
1000 mg tablet (Rocal Jr): Indicated for management of hyperacidity and fast relief of acid indigestion, heartburn, sour stomach, and upset stomach.

Calcium carbonate reacts with gastric acid to form calcium chloride, water, and carbon dioxide.
Raises gastric pH, reduces pepsin activity.
Up to 30% of oral calcium load may be absorbed.

250/500 mg tablet:
- Adults: 540–2000 mg/day (antacid use).
- Children: half adult dose.
- Osteoporosis prevention: 1250–3750 mg/day (500–1500 mg calcium).
- Pregnancy/lactation: 1200–1500 mg/day.
- Chronic renal failure: 2.5–9 g/day, adjusted individually, taken with meals for phosphate binding.
1000 mg tablet: 2000–3000 mg when symptoms occur; may repeat hourly if needed.

Hypercalcemia, hyperparathyroidism
Hypercalciuria, nephrolithiasis
Zollinger‑Ellison syndrome
Concomitant digoxin therapy (requires monitoring)
Use cautiously in sarcoidosis, renal/cardiac disease, or with cardiac glycosides.

Widely used safely in pregnancy and lactation for supplementation or antacid therapy.

Children: Safe and effective in chronic renal failure.
Elderly: Constipation may be troublesome; monitor calcium and phosphate levels.