The P-I-E-N-O Parkinsn's List Drug Database
calcium carbonate / TitralacTM , TumsTM
ANTACID:
Description: Calcium carbonate is an inorganic salt that was once a popular antacid but is now more commonly used as a calcium supplement. Calcium carbonate was in use prior to 1938 and approved by the FDA at its inception.
Mechanism of Action: Calcium is the fifth most abundant element in the body. Calcium is a divalent metal essential for the maintenance of the nervous, muscular, and skeletal systems and for cell membrane and capillary permeability. Its role in bone structure and muscle contraction is well known, but calcium is also important for blood coagulation, nerve conduction, and electrical conduction in the heart. Calcium stimulates gastrin secretion, which offsets the utility of oral calcium carbonate as a treatment of peptic ulcer disease. Calcium and magnesium are, in some ways, physiological opposites, and calcium can be used for the temporary control of cardiac arrhythmias associated with hypokalemia. Finally, growing evidence suggests that calcium accumulates readily in atherosclerotic plaques, although this does not appear to be related to exogenous calcium administration. Parathyroid hormone (PTH), vitamin D, and, to a lesser extent, calcitonin, glucocorticoids, and magnesium influence calcium balance.
Antacids neutralize gastric acid, increasing the pH of the gastric contents, which reduces GI mucosal irritation. The increase in gastric pH inhibits the proteolytic activity of pepsin, which is beneficial to patients with peptic ulcers. The role of calcium carbonate in the treatment of peptic ulcers is questionable, however, because the drug can cause acid rebound. Most clinicians do not use calcium carbonate to treat peptic ulcers, and antacids in general have fallen out of favor due to the availability of HA-blockers.
Calcium carbonate and calcium citrate are useful in treating hyperphosphatemia secondary to chronic renal failure. Oral calcium salts do not extract phosphate from the circulation, as charcoal does to some drugs, but rather bind to dietary phosphate in the gut, preventing its absorption. To accomplish this, it is important to administer the oral calcium salt with meals or snacks because it exerts minimal effects on phosphate once phosphate has been absorbed into the circulation. Calcium binds with phosphate in the gut, forming the insoluble calcium phosphate, which is subsequently eliminated in the stool. Some free calcium, however, can be absorbed, potentially elevating the calcium-phosphorus product. For this reason, it is important to avoid using calcium salts as phosphate binders when serum phosphorus is extremely elevated.
Pharmacokinetics: Calcium carbonate reacts with hydrochloric acid in the stomach to form calcium chloride, carbon dioxide, and water. Most of this calcium chloride (90%) is converted to insoluble salts such as calcium carbonate and calcium phosphate, and these salts are not well absorbed in the intestine. Small amounts of calcium and bicarbonate are absorbed, however, which can cause hypercalcemia. Calcium is excreted in the urine. Hypercalciuria is common in patients receiving calcium carbonate therapy.
CONTRAINDICATIONS/PRECAUTIONS: Patients with preexisting hypercalcemia, renal disease, or dehydration are predisposed to developing milk-alkali syndrome. Symptoms of this syndrome include hypercalcemia, nausea/vomiting, headache, weakness, metabolic alkalosis, and change in mental status. Calcium blood concentrations should be monitored weekly in patients receiving calcium carbonate therapy.
Administration of calcium carbonate can cause gastric hypersecretion and acid rebound. For this reason, calcium carbonate is not a good choice for the treatment of peptic ulcer disease.
Calcium carbonate should be used cautiously in patients with GI bleeding, GI obstruction, constipation, or decreased gastric motility.
DRUG INTERACTIONS: Administration of calcium carbonate concurrently with orally administered tetracyclines or fluoroqinolones can decrease the absorption of antibiotic. This effect presumably is due to the chelation of the antibiotic by the antacid. Oral doses of tetracyclines or quinolones should be given 1-2 hours before or after the administration of antacids, although doxycycline may be affected to a lesser degree than other tetracyclines.
By increasing intragastric pH, calcium carbonate can reduce the oral absorption of iron salts or ketoconazole. In addition, increased intragastric pH can affect the dissolution of oral bisacodyl tablets. These interactions can be minimized by staggering the doses of these agents as much as possible.
By increasing urinary pH, calcium carbonate can decrease the urinary excretion of quinidine or increase the urinary excretion of salicylates. In addition, increased urinary pH can antagonize the actions of either ammonium chloride or methenamine. Staggering the administration times will not prevent this interaction. Calcium carbonate should not be used with urinary acidifiers.
Calcium carbonate potentially interferes with gastric mucosal binding of sucralfate. This interaction can be minimized by staggering the doses of these agents as much as possible.
ADVERSE REACTIONS: Administration of calcium carbonate can cause gastric hypersecretion and acid rebound. For this reason, calcium carbonate is not a good choice for the treatment of peptic ulcer disease. Other GI adverse reactions to calcium carbonate therapy include flatulence, gastric distension, constipation, and eructation.
Large doses of calcium carbonate can lead to the development of hypercalcemia. Hypercalcemia causes symptoms such as anorexia, nausea/vomiting, headache, weakness, dizziness, and altered mental status. Patients with electrolyte imbalances and renal impairment or dehydration are predisposed to developing the milk- alkali syndrome, characterized by hypercalcemia, metabolic alkalosis, and renal failure.
Hypophosphatemia can occur during calcium carbonate therapy if dietary phosphate levels are low. Some oral calcium salts are used clinically to treat hyperphosphatemia in patients with chronic renal failure because calcium will bind with phosphate in the gut and prevent its absorption.
PATIENT INFORMATION:
What do calcium carbonate tablets do?
Calcium carbonate (TitralacTM , TumsTM ) is an antacid that neutralizes or reduces stomach acids. It relieves symptoms in patients with indigestion and heartburn. Calcium carbonate also can be used to prevent stomach bleeding in hospitalized patients or as a dietary calcium supplement. Generic calcium carbonate tablets are available.
What should my doctor, dentist, or pharmacist know before I take calcium carbonate?
They need to know if you have any of these conditions:
How should I take this medicine?
Take calcium carbonate tablets by mouth. Follow the directions on the prescription label. Chew well, or crush the tablets before swallowing; follow with a drink of water. Antacids are usually taken after meals and at bedtime. Take your doses at regular intervals. Do not take your medicine more often than directed.
Special precautions for use in children:
Only give to children on advice from your doctor.
What if I miss a dose?
If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.
What other medicines can interact with calcium carbonate?
Tell your doctor or pharmacist: about all other medicines you are taking, including non-prescription medicines; if you are a frequent user of drinks with caffeine or alcohol; if you smoke; or if you use illegal drugs. These may affect the way your medicine works. Check before stopping or starting any of your medicines.
What side effects may I notice from taking calcium carbonate?
Serious side effects with calcium carbonate are rare and are more likely in patients over 60 years old or patients with severe kidney problems. They include:
Call your doctor as soon as you can if you get any of these side effects.
Let your doctor know about these side effects if they do not go away or if they annoy you.
What do I need to watch for while I take calcium carbonate?
Check with your doctor if calcium carbonate does not relieve your stomach pains; if you get black tarry stools; notice any rectal bleeding; or feel unusually tired. Do not change to another antacid product without advice.
Do not treat yourself for stomach problems with calcium carbonate for more than two weeks without consulting your doctor. A condition known as acid rebound can develop after the initial relief produced by calcium carbonate. Long-term use can make chronic stomach problems worse and is not recommended.
If you are taking other medications, leave an interval of at least 2 hours before or after dosing with calcium carbonate.
Drink several glasses of water a day. This will help to reduce possible constipation.
Where can I keep my medicine?
Keep out of the reach of children in a container that small children cannot open.
Store at room temperature between 15 and 30C (59 and 86F). Throw away any unused medicine after the expiration date.
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