Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1 Pharmacodynamic properties
Pharmacotherapeutic group: antacids, other combinations, ATC code: A02 AX.
Mechanism of action
Rennie Spearmint is a combination of two antacids, calcium carbonate and magnesium carbonate. The mechanism of action of calcium carbonate and magnesium carbonate is local, based on the neutralisation of gastric acid, and is not dependent on systemic absorption.

Pharmacodynamic effects
Calcium carbonate has a rapid, long-lasting and potent neutralising effect. This effect is increased by the addition of magnesium carbonate, which also has a potent neutralising effect. In-vitro studies (with an artificial human stomach model) demonstrate that Rennie increases the pH of the study from 1.5-2.0 to pH 3.0 in 40 seconds and to pH 4.0 in 1 minute and 13 seconds. The maximum pH in this model was pH 5.24.

Clinical efficacy and safety
In healthy volunteers, a significant increase in the pH of the contents of the stomach was reached within 2 minutes following the administration of calcium carbonate and magnesium carbonate. The total neutralising capacity of 2 tablets is 29 mEq/H+ (titration to endpoint pH 2.5).

Pharmacokinetic Properties

5.2 Pharmacokinetic properties
Calcium and magnesium:
In the stomach, calcium carbonate and magnesium carbonate react with the acid in gastric juice to form water and soluble mineral salts.
CaCO3 + 2 HCl -> CaCl2 + H2O + CO2
MgCO3 + 2 HCl -> MgCl2 + H2O + CO2

Calcium and magnesium can be absorbed from these soluble salts. However, the extent of absorption is dependent on the patient and the dose. Less than 10% calcium and 15-20% magnesium is absorbed.
The small quantities of calcium and magnesium absorbed are usually rapidly excreted via the kidneys in healthy individuals. In patients with renal dysfunction, serum concentrations of calcium and magnesium may be elevated.
Due to the effects of various digestive juices outside the stomach, the soluble salts are converted to insoluble salts in the intestinal tract and then excreted with the faeces.