McKenna's Pharmacology for Nursing, 2e

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

combination should be avoided. There is a decrease in effectiveness of warfarin if they are combined, and the person must be monitored very closely and adjust- ments made in the warfarin dose if this combination must be used. There is a decrease in the effectiveness of hormonal contraceptives if they are taken concurrently with these drugs; use of a barrier contraceptive should be suggested.

Implementation with rationale

■ ■ Assure that route of administration is appropriate for each person to ensure therapeutic effects and decrease adverse effects : if used to prevent motion sickness, should be given 30 minutes before activity that involves motion; some oral tablets can be placed in the mouth and allowed to dissolve slowly; rectal suppositories should be inserted high into the rectum; IV infusions should be run slowly, monitoring the person for CNS depression. ■ ■ Assess the person carefully for any potential drug–drug interactions if giving antiemetics in combination with other drugs to avert potentially serious drug–drug interactions. ■ ■ Provide comfort and safety measures, including mouth care, ready access to bathroom facilities, assistance with ambulation and periodic orientation, ice chips to suck, protection from sun exposure and remedial measures to treat dehydration if it occurs, to protect the person from injury and to increase comfort. ■ ■ Provide support and encouragement, as well as other measures (quiet environment, carbonated drinks, deep breathing), to help the person cope with the discomfort of nausea and vomiting and drug effects. ■ ■ Provide thorough teaching, including the drug name and prescribed dosage; the schedule and method for administration; the need to avoid alcohol and other CNS depressants (if the person is not hospitalised); signs and symptoms of adverse effects and measures to minimise or prevent them; the use of sunscreen and protective clothing when outside; comfort measures to reduce feelings of nausea, such as adequate ventilation, deep breathing and a quiet environment; the importance of fluid intake and signs and symptoms of dehydration that should be reported to the healthcare provider; safety measures, such as assistance with ambulation and gradual position changes; the need to notify the healthcare provider before using any OTC medications; 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 (relief of nausea and vomiting). ■ ■ Monitor for adverse effects (dizziness, confusion, GI alterations, cardiac arrhythmias, hypotension, gynaecomastia, pink- to brown-tinged urine, photosensitivity).

Care considerations for people receiving an antiemetic agent

Assessment: History and examination

■ ■ Assess for possible contraindications or cautions : history of allergy to antiemetic to avoid potential hypersensitivity reactions ; impaired renal or hepatic function, which could interfere with the metabolism or excretion of the drug ; coma or semiconscious state, CNS depression or CNS injury, which could be exacerbated by the CNS- depressing effects of the drug ; hypotension or hypertension, which could be affected by the CNS effects of the drug ; active peptic ulcer, which could be exacerbated by the GI effects of the drug ; and current status of pregnancy and breastfeeding because of the potential for adverse effects on the fetus or breastfeeding infant. ■ ■ Perform a physical examination to establish baseline data before beginning therapy and during therapy to determine the effectiveness of the drug and evaluate for the occurrence of any adverse effects associated with drug therapy. ■ ■ Assess the person’s neurological status, including level of orientation, affect and reflexes, to monitor for CNS effects and to rule out underlying CNS problems that could be a contraindication. ■ ■ Assess cardiopulmonary status, including baseline pulse and blood pressure, to evaluate effects on the cardiovascular system. ■ ■ Inspect the skin for colour and evidence of lesion or rash to evaluate for photosensitivity and adverse effects of the drug. ■ ■ Examine the abdomen, including the liver, and auscultate bowel sounds to evaluate GI function and motility, rule out underlying medical problems and identify possible adverse drug effects. ■ ■ Assess complaints of nausea and evaluate emesis; note colour, amount and frequency of vomiting episodes to determine the need for therapy. ■ ■ Monitor laboratory test results, including liver and renal function tests, to monitor for potential problems with metabolism or excretion.