Gastrik

Uses

Adult: One Calcium Carbonate 500 tablet or as directed by the physician. For the prevention of osteoporosis, 1-3 Calcium Carbonate 500 tablet is recommended generally as a dietary supplement . Doses for children is half of those for adults. A large dose should not be taken without physician\'s advice.

Adolescent: One to two Calcium Carbonate tablet daily.

Children: One Calcium Carbonate tablet daily.

Acid regurgitation, Constipation, Gastric ulcer, Gastrointestinal hyperacidity, Heartburn, Indigestion, Non ulcer dyspepsia, Osmotic laxative

Gastrik is also used to associated treatment for these conditions: Acid Reflux, Acid indigestion, Bloating, Calcium Deficiency, Calcium Metabolism Disorders, Calcium and Vitamin D Deficiencies, Colic, Dyspepsia, Gastric Ulcer, Gastroesophageal Reflux, Heartburn, Hemorrhoids, Hot Flushes, Hyperacidity, Hyperphosphataemia, Hypovitaminosis D, Low Bone Density, Osteodystrophy, Osteomalacia, Osteoporosis, Postmenopausal Osteoporosis, Postoperative Gas, Proctitis, Vertebral Fractures, Calcium loss, Gastrointestinal ulceration, Dietary supplementationAcid indigestion, Colic, Constipation, Dyspepsia, Flatulence, Gastric Ulcer, Heartburn, Upset stomach, Antacid therapy, Gastric Acid Suppression

How Gastrik works

Calcium carbonate is a basic inorganic salt that acts by neutralizing hydrochloric acid in gastric secretions. It also inhibits the action of pepsin by increasing the pH and via adsorption. Cytoprotective effects may occur through increases in bicarbonate ion (HCO₃^-) and prostaglandins. Neutralization of hydrochloric acid results in the formation of calcium chloride, carbon dioxide and water. Approximately 90% of calcium chloride is converted to insoluble calcium salts (e.g. calcium carbonate and calcium phosphate).

The suspension of magnesium hydroxide is ingested and enters the stomach. According to the amount ingested, the magnesium hydroxide will either act as an antacid or a laxative.

Through the ingestion of 0.5-1.5 grams (in adults) the magnesium hydroxide will act by simple acid neutralization in the stomach. The hydroxide ions from the magnesium hydroxide suspension will combine with the acidic H+ ions of the hydrochloric acid made by the stomachs parietal cells. This neutralization reaction will result in the formation of magnesium chloride and water.

Through the ingestion of 2-5 grams (in adults) the magnesium hydroxide acts as a laxative in the colon. The majority of the suspension is not absorbed in the intestinal tract and will create an osmotic effect to draw water into the gut from surrounding tissues. With this increase of water in the intestines, the feces will soften and the intraluminal volume of the feces will increase. These effects still stimulate intestinal motility and induce the urge to defecate. Magnesium hydroxide will also release cholecystokinin (CKK) in the intestines which will accumulate water and electrolytes in the lumen and furthermore increase intestinal motility.

Dosage

Gastrik dosage

Calcium Carbonate is always used orally and when used as an antacid the recommended doses for adults are equivalent to 540-2000 mg Calcium Carbonate per day, doses for children being half of those for adults. As a dietary supplement, such as for the prevention of osteoporosis, 1250-3750 mg Calcium Carbonate (500-1500 mg calcium) daily is recommended in general, but again this will need to be tailored to the individual patient depending on any specific disease such as Calcium deficiency, malabsorption or parathyroid function. In pregnancy and lactation therecommended daily dose of calcium is 1200-1500 mg. In chronic renal failure the doses used vary from 2.5 - 9.0 gm Calcium Carbonate per day and need to be adjusted according to the individual patient. To maximize effective phosphate binding in this context the Calcium Carbonate should be given with meals.

Gastrointestinal hyperacidity:

• Adult: Up to 1 g daily, usually given in conjunction with an aluminium-containing antacid eg, aluminium hydroxide.

Osmotic laxative:

• Adult: 2.4-4.8 g daily as a single dose or in divided doses.
• Child: 6-11 yr: 1.2-2.4 g daily; 2-5 yr: 0.4-1.2 g daily. Doses may be given as a single dose or in divided doses.

Side Effects

In rare cases, flatulence, diarrhoea or constipation.

GI irritation, diarrhoea, abdominal cramps; hypermagnesaemia (in patients with renal impairment). Paralytic ileus.

Toxicity

LD50=8500 mg/kg (rat, oral)

Common side effects include drowsiness or flushing (warmth, redness or tingly feeling).

Daily use of magnesium hydroxide can result in fluid and electrolyte disturbances.

Excessive use of the laxative effects of magnesium hydroxide may result in abdominal cramping, nausea and/or diarrhea.

In overdose, symptoms of gastrointestinal irritation and/or watery diarrhea may occur.

Magnesium hydroxide poisoning can result in hypermagnesemia which includes symptoms of: nausea, vomiting, flushing, thirst, hypotension, drowsiness, confusion, loss of tendon reflexes, muscle weakness, respiratory depression, cardiac arrhythmias, coma and cardiac arrest.

Not to be used in individuals with any form of kidney disease or renal failure, a magnesium restricted diet or with any sudden changes in bowel movement lasting over two weeks. Also not to be used in those individuals with abdominal pain, nausea, vomiting, symptoms of appendicitis or myocardial damage, heart block, fecal impaction, rectal fissures, intestinal obstruction or perforation or renal disease. Not to be used in women who are about to deliver as magnesium crosses the placenta and is excreted in small amounts in breast milk.

Using magnesium hydroxide with aluminum hydroxide can decrease the absorption rate of these drugs.

Magnesium hydroxide can react with digoxin, dicoumerol and cimetidine.

Use of ibuprofen with magnesium hydroxide can increase the absorption of the ibuprofen.

Use of magnesium hydroxide with penicallamine, bisphosphates, ketoconazole, quinolones or tetracycline can decrease the absorption of these drugs.

Enteric-coated tablets can be prematurely released when taken with magnesium hydroxide.

It is important to routinely monitor levels of serum magnesium and potassium in patients using magnesium hydroxide. Serum magnesium levels are necessary to determine how much magnesium is being absorbed and how much is being excreted by the kidneys. Excessive diarrhea can occur from use of magnesium hydroxide and thus it is important to also monitor serum potassium levels to ensure hypokalemia does not occur.

Precaution

In the presence of mild hypercalciuria, excretion levels must be carefully monitored and where necessary the dose of calcium carbonate should be reduced or treatment should be stopped. Patients with a history of stone formation should also be recommended to increase their fluid intake. High dosage of vitamin D should be avoided during Calcium therapy unless specifically indicated.

Colostomy, ileostomy; electrolyte imbalance. Monitor for toxicity in patients with impaired renal function. Pregnancy.

Interaction

Oral calcium can reduce internal absorption of tetracycline and fluoride prepa-rations and an interval of at least 3 hours should therefore be allowed between ingestion of these medications. Vitamin D increases internal absorption of calcium. The intestinal uptake of calcium may be reduced by concomitant ingestion of certain foods (e.g. spinach, milk and milk products).

Decreases absorption of tetracyclines and biphosphonates. Separate administration of these and other drugs by around 2 hr.

Volume of Distribution

Calcium is rapidly distributed taken up by skeletal tissues following absorption and distribution into extracellular fluids. Bone contains 99% of the body's calcium and the remaining 1% is approximately equally distributed between intracellular and extracellular fluids.

The peak action and distribution of magnesium hydroxide are variable.

Elimination Route

Maximal absorption occurs at doses of 500 mg or less taken with food. Oral bioavailability depends on intestinal pH, the presence of food and dosage.

About 15%-50% of magnesium hydroxide is absorbed very slowly through the small intestine.

Half Life

N/A

Clearance

Magnesium hydroxide is mainly excreted in the urine by the kidneys. Since the kidneys play a major role in its clearance, individuals with renal failure are at risk of hypermagnesemia with long term consumption as the appropriate amounts of magnesium may not be excreted.

Elimination Route

Excreted mainly in the feces. The majority of renally filtered calcium is reabsorbed in the ascending limb of the loop of Henle and the proximal and distal convoluted tubules. Also secreted by sweat glands.

After oral administration, up to 50% of the magnesium hydroxide suspension may be absorbed as magnesium ions through the small intestines and then rapidly excreted in the urine through the kidneys. The unabsorbed drug is mainly excreted in the feces and saliva.

Pregnancy & Breastfeeding use

Pregnant women : Calcium containing drugs are used widely in pregnancy by way of calcium supplement or antacid therapy. No relationship between malformation in general and calcium exposure has been noted.

Lactating mother : There is no contraindication to the use of calcium carbonate in lactating mother.

Pregnancy category- A.

Contraindication

Hypersensitivity to the Calcium Carbonate or any inactive ingredient of the medication. Hypercalcemia (e.g. in hyperparathyroidism, overdosage of vitamin D, demineralizing tumours such as plasmacytomas and bone metastases), severe hypercalcuria, several renal insufficiency.

Intestinal obstruction, faecal impaction; renal failure; appendicitis.

Special Warning

USE IN CHILDREN: Calcium carbonate has been extensively studied in children and infants with chronic renal failure and is both safe and effective.

USE IN ELDERLY: In case of elderly patients with renal failure when calcium carbonate is taken constipation may be troublesome one for this group. For this reason, monitoring of serum calcium and phosphate is of course indicated for elderly patients.

Storage Condition

Store in a cool, dry place in controlled room temperature.

Innovators Monograph

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