McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 3 1 Adrenergic blocking antagonists

DISCUSSION Propranolol, a non-selective beta-blocker, was prescribed to decrease the tremor he was experiencing. The exact action of this drug to decrease the tremor is thought to be related to its membrane-stabilising properties. The desired therapeutic effect is the reduction of the tremor, but all of the beta-blocking effects will occur and need to be monitored. He did well on the drug until pollen season arrived. That is because propranolol, a non-selective beta- blocker, prevented the compensatory bronchodilation that occurs when the SNS is stimulated. When the pollen reacted with M.R.’s airways, causing them to swell and become narrower, his swollen bronchial tubes were unable to allow air to flow through them. The result was bronchial constriction and respiratory distress that, in M.R.’s case, progressed to a respiratory arrest. Before he began taking propranolol, M.R. probably had been effectively compensating for the swelling of the bronchi through bronchodilation and had never experienced such a reaction. There are few other drugs for treating essential tremor. M.R. and his healthcare providers will need to decide whether the benefit that the drug has brought to him is worth the potential for adverse effects. They might be able to suggest additional drugs to deal with the seasonal allergic reactions to make the use of the propranolol safer for M.R. M.R. may want to discuss this frightening incident with his healthcare provider. He also may want to include his family in this discussion. It should be stressed that he did so well up to this point because he had not been exposed to pollen and therefore had not had the problem that brought him into the hospital this time. M.R. probably never reported the occurrence of hay fever to his healthcare provider when the drug was prescribed because it had never been a problem and probably did not seem significant to him. M.R. and his family should receive support and be encouraged to talk about what happened and how they reacted to it. It is normal to feel frightened and unsure when a loved one is in distress. They should be involved in the discussion of what medical regimen would be most appropriate for M.R. at this point. Review the person’s history for allergy to propranolol, HF, shock, bradycardia, heart block, hypotension, COPD, thyroid disease, diabetes, respiratory impairment, and concurrent use of barbiturates, non-steroidal anti- inflammatory drugs, piroxicam, sulindac, lignocaine, cimetidine, phenothiazines, clonidine, theophylline and rifampicin. Focus the physical examination on the following: CV: blood pressure, pulse, peripheral perfusion, ECG CNS: orientation, affect, reflexes, vision CARE GUIDE FOR M.R.: PROPRANOLOL Assessment: History and examination

Skin: colour, lesions, texture GU: urinary output, sexual function GI: abdominal, liver evaluation Respiratory: respirations, adventitious sounds Implementation

Ensure safe and appropriate administration of the drug. Provide comfort and safety measures: assistance/side rails; temperature control; rest periods; mouth care; small, frequent meals. Monitor blood pressure, pulse, and respiratory status throughout drug therapy. Taper the drug gradually if it is to be discontinued to decrease the risk of severe hypertension, MI or stroke related to abrupt withdrawal. Provide support and reassurance to deal with drug effects and discomfort, sexual dysfunction and fatigue. Provide teaching regarding drug name, dosage, side effects, precautions and warning signs to report. Evaluation Evaluate drug effects: blood pressure within normal limits, decrease in essential tremors, stabilised cardiac rhythm. Monitor for adverse effects: CV effects: HF, block; dizziness, confusion; sexual dysfunction; GI effects; hypoglycaemia; respiratory problems. Monitor for drug–drug interactions as indicated. Evaluate the effectiveness of the teaching program. Evaluate the effectiveness of comfort and safety measures. TEACHING FOR M.R. • The drug that has been prescribed for you, propranolol, is a non-selective beta-adrenergic blocking agent. A beta-adrenergic blocking agent works to prevent certain stimulating activities that normally occur in the body in response to such factors as stress, injury or excitement. It stabilises certain nerve membranes, which helps to decrease your tremor. You should learn to take your pulse and monitor it daily, writing the pulse rate on the calendar. Your current pulse rate is 82 beats/minute. • Never discontinue this medication suddenly. If you find that your prescription is running low, notify your healthcare provider at once. This drug needs to be tapered over time to prevent severe reactions when its use is discontinued. Some of the following adverse effects may occur: • Fatigue, weakness : Try to stagger your activities throughout the day to allow rest periods. • Dizziness, drowsiness : If these should occur, take care to avoid driving, operating dangerous machinery or doing delicate tasks. Change position slowly to avoid dizzy spells. • Change in sexual function : Be assured that this is a drug effect and discuss it with your healthcare provider.