McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 5 7 Drugs affecting gastrointestinal secretions

indigestion, gastric discomfort and dry mouth may also occur. Other adverse effects that have been reported with this drug include dizziness, sleepiness, vertigo, skin rash and back pain. Clinically important drug–drug interactions If aluminium salts are combined with sucralfate, there is a risk of high aluminium levels and aluminium toxicity. Extreme care should be taken if this combination is used. In addition, if phenytoin, fluoroquinolone antibiot- ics (e.g. ciprofloxacin, norfloxacin), or penicillamine is combined with sucralfate, decreased serum levels and drug effectiveness may result. In such combinations, the individual agents should be administered separately, with at least 2 hours between drugs. Prototype summary: Sucralfate Indications: Short-term treatment and maintenance treatment of active duodenal ulcer; treatment of oral and oesophageal ulcers due to radiation, chemotherapy or sclerotherapy. Actions: Forms an ulcer-adherent complex at the duodenal ulcer site, protecting the ulcer from acid, bile salts and pepsin, promoting healing of the ulcer; also inhibits pepsin activity in gastric juices. Pharmacokinetics: Route Onset Duration Oral 30 mins 5 hours T 1/2 : 6 to 20 hours; metabolised in the liver and excreted in faeces. Adverse effects: Sleeplessness, dizziness, vertigo, insomnia, rash, constipation, diarrhoea, nausea, indigestion, dry mouth, back pain.

KEY POINTS

■■ The gastric acid pump or proton pump inhibitors suppress gastric acid secretion by specifically inhibiting the hydrogen–potassium adenosine triphosphatase (H + , K + -ATPase) enzyme system on the secretory surface of the gastric parietal cells. This action blocks the final step of acid production, lowering the acid levels in the stomach. ■■ Proton pump inhibitors are indicated for the short- term treatment of active duodenal ulcer or active benign gastric ulcer; treatment of heartburn or symptoms of gastro-oesophageal reflux; treatment of pathological hypersecretory syndromes; and eradication of H. pylori infection as part of combination therapy GI protectant GI protectants (Table 57.1) coat any injured area in the stomach to prevent further injury from acid. Sucralfate ( Carafate, Ulcyte ) is the only GI protectant currently available. Therapeutic actions and indications Sucralfate forms an ulcer-adherent complex at duodenal ulcer sites, protecting the sites against acid, pepsin and bile salts. This action prevents further breakdown of the area and promotes ulcer healing. The drug also inhibits pepsin activity in gastric juices, preventing further break- down of proteins in the stomach, including the protein wall of the stomach (see Figure 57.1). See Table 57.1 for indications. Pharmacokinetics Sucralfate is rapidly absorbed after oral administration, metabolised in the liver and excreted in faeces. It crosses the placenta and may enter breast milk. Contraindications and cautions Sucralfate should not be given to any person with known allergy to the drug or any of its components to prevent hypersensitivity reactions . It should not be given to individuals with renal failure or undergoing dialysis because a build-up of aluminium may occur if it is used with aluminium-containing products. Caution should be used in women who are pregnant or breastfeeding because of the potential adverse effects on the fetus or neonate . Adverse effects The adverse effects associated with sucralfate are pri- marily related to its GI effects. Constipation is the most frequently seen adverse effect. Diarrhoea, nausea,

Care considerations for people receiving a GI protectant

Assessment: History and examination

■ ■ Assess for possible contraindications or cautions : any history of allergy to sucralfate to prevent hypersensitivity reactions ; renal dysfunction or dialysis, which can lead to a build-up of aluminium ; and current status of pregnancy or breastfeeding. ■ ■ Perform a physical examination to establish baseline data before beginning therapy, to determine the effectiveness of therapy and to evaluate for any adverse effects associated with drug therapy.