Calcium carbonate tablets (Caltan) mainly exert physiological effects by supplementing calcium, and their effectiveness is closely related to the method of medication. At the same time, attention should be paid to the interaction of multiple drugs, which may affect the efficacy or increase the risk. The following provides specific explanations from three aspects: mechanism of action, clinical efficacy, and drug interactions.

1. Mechanism and effect of action

(1) Calcium supplementation directly provides calcium ions to participate in bone formation, with each tablet containing about 400mg of elemental calcium. The fasting absorption rate is about 30%, and it increases to 35-40% after meals.

(2) Neutralizing effect of gastric acid

Converted into calcium chloride in the stomach, it can temporarily alleviate symptoms of excessive stomach acid, but its sustained effect is weaker than aluminum magnesium antacids.

(3) Blood calcium regulation

After oral administration, the peak blood calcium concentration is reached within 4-6 hours, and about 80% of unabsorbed calcium is excreted through feces within 24 hours, maintaining blood calcium homeostasis.

2 Clinical efficacy characteristics

(4) Continuous medication for 6 months can increase bone density by 2-3% for osteoporosis prevention, and vitamin D should be combined to promote calcium deposition.

(5) Correction of hypocalcemia

The therapeutic dose can increase blood calcium levels by 0.1-0.2mmol/L daily, and in severe cases, intravenous calcium supplementation is needed as an adjunct.

(6) Application during pregnancy

It can reduce the risk of gestational hypertension by 37%, but excessive use may inhibit fetal parathyroid development.

3 drug interactions

(7) Antibiotics form chelates with tetracyclines and quinolones to reduce their efficacy, and should be taken at intervals of at least 2 hours.

(8) Thyroid preparations

Calcium carbonate can adsorb levothyroxine, reducing absorption by 40%. It is recommended to administer it every 4 hours.

(9) Diuretics

Thiazide diuretics increase calcium reabsorption, and when used in combination, blood calcium should be monitored to prevent excessive levels.

(10) Cardiac glycosides

Hypercalcemia may enhance the toxicity of digoxin, and regular monitoring of electrocardiogram and blood drug concentration is necessary.

(11) Phosphate preparations

Simultaneous use may cause abnormal calcium and phosphorus deposition, and patients with renal dysfunction should strictly avoid combination therapy.