McKenna's Pharmacology for Nursing, 2e

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P A R T 1 1  Drugs acting on the gastrointestinal system

replacement in conditions that result in lower-than-nor- mal levels of these enzymes. Therapeutic actions and indications The pancreatic enzymes are replacement enzymes that help the digestion and absorption of fats, proteins and carbohydrates (see Figure 57.1). See Table 57.2 for usual indications for each agent. Pharmacokinetics Pancrelipase, which is available in capsules, delayed release capsules, granules and tablet form, is thought to be processed through normal metabolic systems in the body. Little is known about its pharmacokinetics. Contraindications and cautions Pancreatic enzymes should not be used with known allergy to the product or to pork products to prevent hypersensitivity reactions . In addition, pancreatic enzymes should be used cautiously in pregnancy and breastfeeding because of the risk for adverse effects on the fetus or baby . Adverse effects The adverse effects that most often occur with pancre- atic enzymes are related to GI irritation and include nausea, abdominal cramps and diarrhoea. Prototype summary: Pancrelipase Indications: Replacement therapy in people with deficient exocrine pancreatic secretions. Actions: Replaces pancreatic enzymes to aid in the digestion and absorption of fats, proteins and carbohydrates. Pharmacokinetics: Generally not absorbed systemically. T 1/2 : Generally not absorbed systemically. Adverse effects: Nausea, abdominal cramps, diarrhoea, hyperuricosuria.

■■ The prostaglandin misoprostol is used to inhibit gastric acid secretion and increase bicarbonate and mucus production in the stomach; this action will protect the lining of the stomach. ■■ This drug increases prostaglandin effects in the uterus, causing increased contractions, excessive bleeding and cramping. This drug is pregnancy category X and cannot be used during pregnancy. DIGESTIVE ENZYMES Digestive enzymes (Table 57.2) are substances produced in the GI tract to break down foods into usable nutri- ents. Some people—with cystic fibrosis or pancreatic dysfunction resulting from surgery or illness—may require a supplement to the production of digestive enzymes. Pancrelipase ( Creon , Panzytrat ) is available for measures such as small, frequent meals and increased fluid intake to alleviate or minimise adverse GI effects; danger signs to report to the healthcare provider immediately; support to deal with changes in sexuality patterns that may occur; and the importance of periodic monitoring and evaluation to enhance knowledge about drug therapy and to promote compliance. Evaluation ■ ■ Monitor the response to the drug (prevention of GI ulcers related to NSAIDs). ■ ■ Monitor for adverse effects (GI, genitourinary). ■ ■ Monitor the effectiveness of comfort and safety measures and compliance with the regimen. ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug and dosage and describe adverse effects to watch for, specific measures to avoid them and measures to take to increase the effectiveness of the drug). KEY POINTS

TABLE57.2

DRUGS IN FOCUS Drug used to treat digestive enzyme dysfunction

Drug name

Dosage/route

Usual indications

Digestive enzymes

Adult: 4000–48,000 units PO with each meal and snacks Paediatric: 6 months–1 year: 2000 units PO per meal 1–6 years: 4000–8000 units PO with meals, 4000 units with snacks 7–12 years: 4000–12,000 units PO with each meal and snack

Aids digestion and absorption of fats, proteins and carbohydrates in conditions that result in a lack of this enzyme; used as replacement therapy in people with cystic fibrosis, chronic ductal obstruction, pancreatic insufficiency, steatorrhoea or malabsorption syndrome and after pancreatectomy or gastrectomy

pancrelipase (Creon, Panzytrat)