McKenna's Pharmacology for Nursing, 2e

31

Adrenergic blocking antagonists

Learning objectives Upon completion of this chapter, you should be able to: 1. Describe the effects of adrenergic blocking agents on adrenergic receptors, correlating these effects with their clinical effects. 2. Describe the therapeutic actions, indications, pharmacokinetics, contraindications and cautions, most common adverse reactions and important drug–drug interactions associated with adrenergic blocking agents. 3. Discuss the use of adrenergic blocking agents across the lifespan. 4. Compare and contrast the prototype drugs labetalol, phentolamine, doxazosin, propranolol and atenolol with other adrenergic blocking agents. 5. Outline the care considerations, including important teaching points, for people receiving an adrenergic blocking agent.

Test your current knowledge of adrenergic blocking antagonists with a PrepU Practice Quiz!

Glossary of key terms adrenergic-receptor-site specificity: a drug’s affinity for only adrenergic receptor sites; certain drugs may have specific affinity for only alpha- or only beta-adrenergic receptor sites alpha 1 -selective adrenergic blocking agents: drugs that block the postsynaptic alpha 1 -receptor sites, causing a decrease in vascular tone and a vasodilation that leads to a fall in blood pressure; these drugs do not block the presynaptic alpha 2 -receptor sites, and therefore the reflex tachycardia that accompanies a fall in blood pressure does not occur beta-adrenergic blocking agents: drugs that, at therapeutic levels, selectively block the beta-receptors of the sympathetic nervous system beta 1 -selective adrenergic blocking agents: drugs that, at therapeutic levels, specifically block the beta 1 -receptors in the sympathetic nervous system while not blocking the beta 2 -receptors and resultant effects on the respiratory system bronchodilation: relaxation of the muscles in the bronchi, resulting in a widening of the bronchi; an effect of sympathetic stimulation phaeochromocytoma: a tumour of the chromaffin cells of the adrenal medulla that periodically releases large amounts of noradrenaline and adrenaline into the system with resultant severe hypertension and tachycardia sympatholytic: a drug that lyses, or blocks, the effects of the sympathetic nervous system

NON-SELECTIVE ADRENERGIC BLOCKING AGENTS amiodarone carvedilol labetalol

ALPHA 1 -SELECTIVE ADRENERGIC BLOCKING AGENTS alfuzosin doxazosin prazosin tamsulosin terazosin

NON-SELECTIVE BETA- ADRENERGIC BLOCKING AGENTS nebivolol oxprenolol pindolol propranolol

BETA 1

-SELECTIVE ADRENERGIC

BLOCKING AGENTS atenolol

betaxolol bisoprolol esmolol metoprolol

NON-SELECTIVE ALPHA-ADRENERGIC BLOCKING AGENTS phentolamine

sotalol timolol