McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 4 5 Antiarrhythmic agents

■ ■ Ensure that emergency life support equipment is readily available to treat severe adverse reactions that might occur. ■ ■ Administer parenteral forms as ordered only if the oral form is not feasible; expect to switch to the oral form as soon as possible to decrease the potential for severe adverse effects. ■ ■ Consult with the prescriber to reduce the dose in people with renal or hepatic dysfunction; reduced dose may be needed to ensure therapeutic effects without increased risk of toxic effects. ■ ■ Establish safety precautions, including side rails, lighting and noise control, if CNS effects occur to ensure the person’s safety. ■ ■ Arrange for periodic monitoring of cardiac rhythm when the person is receiving long-term therapy to evaluate effects on cardiac status. ■ ■ Provide comfort measures to help the person tolerate drug effects. These include small, frequent meals to minimise nausea and vomiting; access to bathroom facilities; bowel program as needed to deal with nausea, vomiting and constipation ; administration of food with drug if GI upset is severe to alleviate the discomfort ; environmental controls, such as temperature regulation, light control and decreased noise, to alleviate THE SITUATION R.A., a 63-year-old man, developed atrial fibrillation 2 years ago, with a rapid drop in blood pressure and a rapid pulse of 160 beats/minute, irregularly irregular. He was cardioverted within a few hours of onset to normal sinus rhythm with a heart rate of 74 beats/minute. He was started on digoxin ( Lanoxin ) and remained stable for more than a year. It was decided to stop the drug and monitor R.A. He did well, but on a long-awaited trip to Italy, he again developed atrial fibrillation, with rapid pulse and drop in blood pressure. He was treated at an Italian clinic with cardioversion and seen by his cardiologist on his return to Australia. He was again placed on digoxin to maintain his conversion to sinus rhythm. He called the clinic with complaints of palpitations and a severe headache and was told to immediately come in to be evaluated. He was found to be in sinus rhythm with PVCs. He stated that he felt that the headache was related to a cold he had been fighting, and he has been self-medicating with antihistamines.

overstimulation if CNS effects occur ; and reorientation as needed. ■ ■ Offer support and encouragement to help the person to deal with the diagnosis and the drug regimen. ■ ■ Provide thorough teaching, including the name of the drug, dosage prescribed, measures to avoid adverse effects, warning signs of problems and the need for periodic monitoring and evaluation, to enhance knowledge about drug therapy and to promote compliance. Evaluation ■ ■ Monitor response to the drug (stabilisation of cardiac rhythm and output). ■ ■ Monitor for adverse effects (sedation, hypotension, cardiac arrhythmias, respiratory depression, CNS effects). ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, adverse effects to watch for, specific measures to avoid them and the importance of continued follow-up). ■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen. See the Critical thinking scenario for information on managing the person on chronic antiarrhythmic therapy. CRITICAL THINKING Based on your knowledge of the drug digoxin and the symptoms reported by R.A, what do you think happened? What actions should be taken at this time to make sure that R.A.’s heart rhythm remains stable? What teaching points will be essential to convey to R.A. before he goes home? What other screening should be done at this time to prevent problems in the future? DISCUSSION R.A. has the signs and symptoms of increased digoxin levels—headache and ventricular arrhythmias. Initially, R.A. should be placed on a cardiac monitor and supported to ensure that the ventricular arrhythmias do not progress. His digoxin should be stopped until the situation is stabilised. Emergency life support equipment should be readily available in case the situation deteriorates.

CRITICAL THINKING SCENARIO Managing people on chronic antiarrhythmic therapy