Pharmacology and Nutrition

LEARNING OUTCOMES

After studying this chapter, the student will be able to:

1. Explain the difference between systemic and non-systemic antacids and give

an example of each

2. Describe three ways that antacids may interact with other drugs

3. Apply the nursing process related to caring for clients receiving antacid therapy

 

Antacids are alkaline chemical agents used for relief of symptoms associated with hyperacidity and peptic ulcer disease (PUD). There is considerable controversy as to the function of antacids in treating these common gastrointestinal disorders. Although it has long been established that antacids reduce the corrosiveness of gastric acid and decrease

pepsin activity, there is little conclusive evidence to support the contention that antacids enhance the healing, decrease the frequency, or prevent the recurrence of peptic ulcers.

The primary goal of antacid therapy is the relief of pain. The pain-reducing effect of antacids is believed to be due to their:

acid neutralizing capacity inhibition of the protein-digesting ability of pepsin

action to increase the resistance of the stomach lining to irritation

ability to increase the tone of the lower esophageal sphincter

This latter action is believed to explain why antacids are effective in reducing pain associated

with gastroesophageal reflux (GER).

Selection of the proper antacid is important because most clients on antacid therapy will be

using large doses for a prolonged time. An ideal antacid product:

effectively neutralizes large volumes of acid with a reasonably small dose.

avoids causing “acid rebound.” This is a phenomenon characterized by the production of

greater than normal volumes of acid by the stomach when the pH of its contents is raised

above the desirable 4–5 range. Above this level, the stomach responds to alkalinization

by secreting more acid, thereby returning the client to a state of hyperchlorhydria.

has a prolonged action. It should provide prompt relief and then continue to provide relief for several hours. This is an important feature, as the client may not take the medication as directed if the antacid must be administered too frequently. In other words, client cooperation is more likely if relief continues for some time after the antacid is taken.

does not interfere with the digestion or absorption of nutrients or drugs. Many antacids

form chemical complexes with drugs such as the tetracycline antibiotics. When these drugs

form complexes, the tetracycline is not absorbed well from the gastrointestinal tract

and is not as effective. Antacids should, therefore, not be administered within 2 hours of

an oral dose of a tetracycline. Antacids have also been found to adsorb certain drugs onto

their surface—that is, the drug sticks to the surface of the antacid particles. Some

antacids may slow or impair the absorption of digoxin.

 

Active Ingredients in Antacid Products

ü  Administration with other drugs or food may reduce the absorption of these agents.

ü  Do not take other oral drugs within 1–2 hours of antacid administration.

ü  Monitor quality and consistency of stool during antacid therapy.

ü  Shake liquid antacid products well prior to use.

ü  Follow administration of antacid with a small amount of water or milk to facilitate passage into stomach.

ü  Do not administer within 1–2 hours of any enteric-coated drug product.

ü  Assess the client’s response to antacid use

 

KEY NURSING IMPLICATIONS

Antacids

1. Maintain a schedule for antacid administration. Antacids should be administered

following meals or a snack.

2. Shake all liquid preparations thoroughly and instruct clients to chew tablets well

and to follow the tablets with water.

3. Avoid the use of aspirin, ibuprofen and naproxen in clients with peptic ulcer disease.

4. Discuss the development of diarrhea or constipation with the prescriber.

5. Avoid simultaneous administration of antacids and antibiotics

 

Antispasmodics that Are Belladonna Derivatives

ü  Administration is contraindicated in clients with narrow-angle glaucoma, renal disease, prostatic hypertrophy, obstructive disease of the GI tract, or preoperatively for open heart surgery.

ü  May reduce tolerance to high environmental temperature.

ü  Administer 30–60 minutes before meals and at bedtime.

ü  Gum, hard candy, or ice chips may be provided to relieve dry mouth.

ü  Monitor client for development of constipation, reduced urinary output, skin rash, flushing, or eye pain.

ü  Elderly clients may develop excitement, confusion, agitation, or drowsiness.

ü  Diminished doses should be used in the elderly.

ü  Neostigmine methylsulfate (0.5–2 mg) may be given intravenously to treat overdose. Physostigmine (1–4 mg)

ü  administered by slow IV injection also has been successfully used to reverse anticholinergic effects.

ü  Assess client for therapeutic effectiveness.

 

Synthetic Anticholinergics Used as Antispasmodics

ü  Administration is contraindicated in clients with narrow-angle glaucoma, renal disease, prostatic hypertrophy, obstructive disease of the GI tract, or preoperatively for open-heart surgery.

ü  May reduce tolerance to high environmental temperature (impairs ability to perspire).

ü  Administer 30–60 minutes before meals and at bedtime.

ü  Gum, hard candy, or ice chips may be provided to relieve dry mouth.

ü  Monitor client for development of constipation, reduced urinary output, skin rash, flushing, or eye pain.

ü  Elderly clients may develop excitement, confusion, agitation, or drowsiness.

ü  Diminished doses should be used in the elderly.

ü  Assess client for therapeutic effectiveness.

 

KEY NURSING IMPLICATIONS

Antispasmodics

1. Clients noting blurred vision, headache, urinary retention, palpitations, and indications of glaucoma are referred to the physician.

2. Antispasmodics should not be administered to clients with acute, narrow-angle glaucoma.

3. Carefully monitor elderly clients receiving antispasmodics and notify the physician if

urinary retention or indications of acute glaucoma occur.

4. Tincture of belladonna may be mixed in a small amount of applesauce or juice to mask its unpleasant taste.

5. Mouth care and sucking on hard candy may help to relieve dry mouth.

 

 

 

OTHER AGENTS AFFECTING GASTROINTESTINAL FUNCTION

Laxatives are drugs intended to facilitate the passage and elimination of feces from the colon and rectum.

They are used to:

§  prepare clients for a lower GI X-ray series or surgery

§  reduce the strain of defecation in clients with cardiovascular disease or in postoperative clients

§  diagnose and treat parasitic infestations of the GI tract

§  help remove unabsorbed poisons from the GI tract when oral poisonous substances have been consumed prevent or treat constipation

Laxative use by the general public is widespread but controversial because of the lack of objective data to justify their routine use. Most laxatives are used to either prevent or treat constipation.

 

Stimulant Laxatives

§  Contraindicated for use in clients with abdominal pain, nausea, vomiting, or rectal fissures.

§  Should only be used for short-term treatment.

§  Evaluate effectiveness of laxative.

Saline Laxatives

§  Should only be used for short-term treatment.

§  Contraindicated for use in clients with abdominal pain, nausea, vomiting, or other symptoms of appendicitis.

§  Evaluate the effectiveness of laxative.

Bulk-forming Laxatives

§  Laxative effect may not be evident for up to 3 days.

§  Contraindicated for use in clients with abdominal pain, nausea, vomiting or other symptoms of appendicitis.

§  Should be mixed with cold liquid and drunk immediately. Follow with another glass of liquid.

§  Evaluate effectiveness of laxative

Stool Softeners

§  Liquid dosage form may be given in milk, fruit juice, or formula to mask taste.

§  Action may not be evident for up to 3 days.

§  Prevents development of constipation. However, it is not used to treat existing constipation.

§  Avoid use for longer than 1 week.

§  Evaluate client for the effectiveness of these agents.

KEY NURSING IMPLICATIONS

Laxatives

1. In selecting a laxative, consider the age and general condition of the client, special restrictions due to illness, the client’s past experience with laxatives, and the time at which evacuation is desired.

2. In general, avoid the use of stimulant laxatives in the elderly.

3. Nondrug measures, such as dietary modification, fluid intake, and exercise, should

be encouraged to promote regularity.

4. Disguise the taste of castor oil.

5. Inform clients using laxatives, such as phenolphthalein and senna, that they discolor urine or feces.

6. Follow bulk-forming laxatives with at least 1 glass of fluid to prevent gastrointestinal obstruction.

7. Avoid rushing or distracting clients taking lubricant laxatives in order to prevent aspiration.

8. Support is necessary for clients taking fecal wetting agents, because they are

slow in producing effects.

9. Instruct clients using suppositories at home about proper storage and administration.

10. Always assess the effectiveness of laxatives.

11. Never administer laxatives to clients experiencing abdominal pain, nausea or

vomiting until you have consulted their physician.

12. Inform clients taking laxatives that they must drink 6–8 glasses of water to avoid

dehydration

 

KEY NURSING IMPLICATIONS

Antidiarrheal Agents

1. Monitor fluid intake and output and record information about the frequency

and nature of stools. Monitor body weight in infants.

2. Observe clients receiving paregoric, diphenoxylate HCl (Lomotil), difenoxin

(Motofen), or loperamide (Imodium) for CNS depression.

3. Adsorbents should not be taken within several hours of taking other oral

medications.

4. Lactobacillus products must be refrigerated.

5. Refer adult clients with fever, dehydration, or diarrhea persisting for several days to a

physician.

6. Infants and young children must be referred sooner.

 

KEY NURSING IMPLICATIONS

Emetics and Antiemetics

1. Identify the toxic substance ingested and call a poison control center for information.

2. Emetics are not administered to persons who have swallowed corrosive substances

or oils or to those who are unconscious.

3. Antiemetics are used carefully in clients taking other drugs with a CNS depressant

effect and are best avoided in pregnant women.