McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 4 4 Cardiotonic agents

G.J. was treated with diuretics and was redigitalised in the hospital with close cardiac monitoring. After her condition stabilised, G.J. reported that she knew she had been taking her digoxin every day because she recognised the pill. The only difference she could identify was that she was given the pill in the afternoon with a dish of ice cream, while at home she always took it on an empty stomach first thing in the morning. The nursing home staff confirmed that G.J. had received the drug daily in the afternoon and that it was the same brand name she had used at home. CRITICAL THINKING What care interventions should be made at this point? Think about the signs and symptoms of HF and how they show its progression. How could the change in the timing of drug administration be related to the decreased serum digoxin levels noted on G.J.’s admission? Consider the factors that affect absorption of a drug. What alterations in dosing could be suggested that would prevent this from happening to G.J. again? What potential problems with trust could develop for G.J. on her return to the nursing home? Suggest an explanation for what happened to G.J. and possible ways that this problem could have been averted. DISCUSSION G.J.’s immediate needs involve trying to alleviate the alteration to her cardiac output that occurred when she lost the therapeutic effects of digoxin. Positioning, cool environment, small and frequent meals, and rest periods can help to decrease the workload on her heart. Digoxin has a narrow margin of safety and requires an adequate serum level to be therapeutic. G.J. was not absorbing enough digoxin to achieve a therapeutic serum level; consequently, her body began to go through the progression of HF, first right-sided and then left-sided. CARE GUIDE FOR G.J.: DIGOXIN Assessment: History and examination Assess the person’s health history for allergies to any digitalis product, renal dysfunction, idiopathic hypertrophic subaortic stenosis (IHSS), pregnancy, breastfeeding, arrhythmias, heart block and electrolyte abnormalities. Focus the physical examination on the following areas: Cardiovascular: blood pressure, pulse, perfusion, ECG Neurological (CNS): orientation, affect, reflexes, vision Skin: colour, lesions, texture, perfusion Respiratory system: respiratory rate and character, adventitious sounds

GI: abdominal examination, bowel sounds Laboratory tests: serum electrolytes, body weight Implementation Administer a loading dose to provide rapid therapeutic effects. Monitor apical pulse for 1 full minute before administering to assess for adverse and therapeutic effects. Check dose very carefully. Provide comfort and safety measures: give small, frequent meals; ensure access to bathroom facilities; avoid intramuscular injection; administer intravenously over 5 minutes; keep emergency equipment on standby. Provide support and reassurance to deal with drug effects. Provide teaching regarding drug, dosage, adverse effects, what to report, safety precautions. Evaluation Evaluate drug effects: relief of signs and symptoms of HF, resolution of atrial arrhythmias, serum digoxin levels 0.5 to 2 ng/mL. Monitor for adverse effects, including arrhythmias, vision changes (yellow halo), GI upset, headache, drowsiness. Monitor for drug–drug interactions as indicated for each drug. Evaluate the effectiveness of teaching program. Evaluate the effectiveness of comfort and safety measures. TEACHING FOR G.J. • Digoxin is a digitalis preparation. Digitalis has many helpful effects on the heart; for example, it helps the heart to beat more slowly and efficiently. These effects promote better circulation and should help to reduce the swelling in your ankles or legs. It also should increase the amount of urine that you produce every day. • Digoxin is a very powerful drug and must be taken exactly as prescribed. It is important to have regular medical checkups to ensure that the dose of the drug is correct for you and that it is having the desired effect on your heart. • Do not stop taking this drug without consulting your healthcare provider. Never skip doses and never try to “catch up” any missed doses, because serious adverse effects could occur. • Learn to take your pulse. Take it each morning before engaging in any activity. Write your pulse rate on a calendar so you will be aware of any changes and can notify your healthcare provider if the rate or rhythm of your pulse shows a consistent change. Your normal pulse rate is __________. • Try to monitor your weight fairly closely. Weigh yourself every other day, at the same time of the day and in the same amount of clothing. Record your weight on your calendar for easy reference. If you gain or lose 1.5 kg or more in 1 day, it may indicate a problem with your drug. Consult your healthcare provider.