McKenna's Pharmacology for Nursing, 2e

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

Care considerations for people receiving non-selective adrenergic blocking agents

■ ■ Encourage the person to adopt lifestyle changes, including diet, exercise, smoking cessation and stress reduction, to aid in lowering blood pressure. ■ ■ Assess heart rate for changes that might suggest arrhythmias. Obtain blood pressure in various positions to assess for orthostatic hypotension. ■ ■ Institute safety precautions especially if the person complains of dizziness, fatigue or vertigo or if orthostatic hypotension occurs to prevent injury to the person. ■ ■ Monitor GI function and need for increased access to bathroom facilities and need for increased fluid intake related to diarrhoea. ■ ■ Monitor for any sign of liver failure to arrange to discontinue the drug if this occurs (this effect is more likely to happen with carvedilol). ■ ■ Offer support and encouragement to help the person deal with the drug regimen. ■ ■ Provide thorough teaching, including drug name, dosage and schedule for administration; measures to prevent adverse effects and warning signs of problems; the need to avoid herbal or alternative therapies unless allowed by the prescriber; and safety measures, such as changing position slowly and avoiding driving or operating hazardous machinery; and the need for monitoring and evaluation to enhance knowledge about drug therapy and to promote compliance. Evaluation ■ ■ Monitor response to the drug (improvement in blood pressure and HF). ■ ■ Monitor for adverse effects (CV changes, headache, GI upset, bronchospasm, liver failure). ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, adverse effects to watch for, specific measures to avoid adverse effects). ■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen.

Assessment: History and examination

■ ■ Assess for contraindications or cautions: any known allergies to these to avoid hypersensitivity reactions ; presence of bradycardia or heart blocks, which could be worsened by the slowing of heart rate and conduction ; asthma or bronchospasm, which could be exacerbated by the loss of the bronchodilation effect of noradrenaline ; shock or HF, which could worsen with the loss of the sympathetic reaction ; diabetes, which could be aggravated by the blocking of the sympathetic response and the masking of the usual signs and symptoms of hypoglycaemia and hyperglycaemia ; and pregnancy or breastfeeding status because of the potential adverse effects on the fetus or neonate. ■ ■ Perform a physical assessment to establish baseline data for determining the effectiveness of the drug and the occurrence of any adverse effects associated with drug therapy ; assess the level of orientation and for any complaints of dizziness, paraesthesias or vertigo. ■ ■ Monitor vital signs and assess cardiovascular status, including pulse, blood pressure and cardiac output, to evaluate for possible cardiac effects ; obtain an electrocardiogram (ECG) as ordered to assess for possible irregularities in rate or rhythm ; assess respiratory rate and auscultate lungs to determine the presence of any adventitious sounds ; observe for ease of breathing, and report any signs and symptoms of bronchospasm or respiratory distress; and monitor GI activity to determine the need for interventions to deal with increased activity. ■ ■ Monitor the results of laboratory tests such as renal and liver function studies and electrolyte levels to determine the need for possible dose adjustment ; monitor blood glucose levels to evaluate for hyper- or hypoglycaemia. ■ ■ Do not discontinue abruptly after chronic therapy because hypersensitivity to catecholamines may develop and the person could have a severe reaction ; taper drug slowly over 2 weeks, monitoring the person. ■ ■ Consult with the doctor about withdrawing the drug before surgery because withdrawal is controversial; effects on the sympathetic system after surgery can cause problems. Implementation with rationale

KEY POINTS

■■ Adrenergic blocking agents block the effects of the SNS. ■■ The non-selective adrenergic blocking agents block all receptors, that is, both alpha- and beta-receptors. ■■ Selective adrenergic blocking agents have specific affinity for alpha- or beta-receptors or for specific alpha 1 -, alpha 2 -, beta 1 - or beta 2 -receptor sites. ■■ Blocking all of the receptor sites within the SNS results in a lowering of blood pressure.