Antacids

Antacids are used to chemically react with and neutralize the acid in the stomach. They can provide rapid relief from increased acid levels. They are known to cause GI alterations such as diarrhea or constipation and can alter the absorption of many drugs.

Antacids: Generic and Brand Names

Here is a list of the most commonly encountered antacids and their brand names.

• Antacids

• aluminum salts (AlternaGel)

• calcium salts (Oystercal, Tums)

• magaldrate (Losopan, Riopan)

• magnesium salts (Milk of Magnesia, others)

• sodium bicarbonate (Bell-ans)

Disease Spotlight: Ulcer Disease

Erosions in the lining of the stomach and adjacent areas of the GI tract are called peptic ulcer.

• Ulcer patients present with a predictable description of gnawing, burning pain often occurring a few hours after meals.

• Many of the drugs that are used to affect GI secretions are designed to prevent, treat, or aid in the healing of these ulcers.

• Further research led many to believe that, because acid production was often normal in ulcer patients, ulcers were caused by a defect in the mucous lining that coats the inner lumen of the stomach to protect it from acid and digestive enzymes.

• Treatment was aimed at improving the balance between the acid produced and the mucous layer that protects the stomach lining.

What are antacids?

Antacids are a group of inorganic chemicals that neutralize stomach acid.

• Antacids are available OTC, and many patients use them to self-treat a variety of GI symptoms.

• The choice of an antacid depends on adverse effects and absorption factors.

Therapeutic actions

The desired actions of antacids include the following:

• Neutralize stomach acid by direct chemical reaction.

• Symptomatic relief of an upset stomach associated with hyperacidity, as well as the hyperacidity associated with peptic ulcer, gastritis, peptic esophagitis, gastric hyperacidity, and hiatal hernia.

Indication

Antacids are indicated for the following:

• Symptomatic relief of GI hyperacidity, treatment of hyperphosphatemia, prevention of formation of phosphate urinary stones.

• Treatment of calcium deficiency, prevention of hypocalcemia.

• Prophylaxis of stress ulcers, relief of constipation.

Pharmacokinetics

Many of these antacids are available in combination forms to take advantage of the acid-neutralizing effect and block adverse effects.

Route	Onset	Peak	Duration
Oral	Rapid	30 min	1-3h
IV	Immediate	Rapid	Unknown
T 1/2: Unknown
			Excretion: Unchanged in urine

Contraindications and Cautions

The following are contraindications and cautions when using antacids:

• Allergy. The antacids are contraindicated in the presence of any known allergy to antacid products or any component of the drug to prevent hypersensitivity reactions.

• Co-morbidities. Caution should be used in the following instances: any condition that can be exacerbated by electrolyte or acid-based imbalance to prevent exacerbations and serious adverse effects; any electrolyte imbalance , which could be exacerbated by the electrolyte-changing effects of these drugs; GI obstruction which could cause systemic absorption of the drugs and increase adverse effects; renal dysfunction, which could lead to electrolyte disturbance if any absorbed antacid is neutralized properly.

• Pregnancy and lactation. Antacids are contraindicated for pregnant and lactating women because of the potential for adverse effects on the fetus or neonate.

Adverse effects

Adverse effects when using antacids include:

• GI: Gastric rupture.

• Systemic alkalosis: headache, nausea, irritability, weakness, tetany, confusion.

• Misc: Hypokalemia.

Interactions

Antacids can greatly affect the absorption of drugs from the GI tract.

• Alkalinity. Most drugs are prepared for an acidic environment, and an alkaline environment can prevent them from being broken down for absorption or can actually neutralize them so that they cannot be absorbed.

Nursing considerations

Nursing considerations for a patient using antacids include the following:

Nursing Assessment

History taking and physical exam in a patient using antacids include:

• Assess for possible contraindications and cautions: any history of allergy to antacids to prevent hypersensitivity reactions; renal dysfunction, which might interfere with the drug’s excretion; electrolyte disturbances, which could be exacerbated by effects of the drug; and current status of pregnancy or lactation due to possible effects on the fetus or newborn.

• Perform a physical examination to establish baseline data before beginning therapy, determine the effectiveness of the therapy, and evaluate for any potential adverse effects associated with the drug.

• Inspect the abdomen; auscultate bowel sounds to ensure GI motility.

• Assess mucous membrane status to evaluate potential problems with absorption and hydration.

• Monitor laboratory test results, including serum electrolyte levels and renal function tests, to monitor for adverse effects of the drug and potential alterations in excretion that may necessitate dose adjustment.

Nursing Diagnosis and Care Planning

Nursing diagnoses related to drug therapy might include the following:

• Diarrhea related to GI effects.

• Risk for constipation related to GI effects.

• Imbalanced nutrition: less than body requirements related to GI effects.

• Risk for imbalanced fluid volume related to systemic effects.

• Deficient knowledge regarding drug therapy.