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C H A P T E R 3 0 Adrenergic agonists

receptors in the SNS, and a -specific and b -specific adrenergic agonists, which stimulate only a - or only b -receptors, respectively. ■■ a -specific adrenergic agonists, such as phenylephrine and clonidine, stimulate only the a -receptors within the SNS. Clonidine specifically stimulates a 2 -receptors and is used to treat hypertension because its action blocks the release of noradrenaline from nerve axons. ■■ Many of the b 2 -specific adrenergic agonists are used to manage and treat asthma, bronchospasm and other obstructive pulmonary diseases. ■■ Isoprenaline, a non-specific b -specific adrenergic, is used to treat shock, cardiac standstill and certain arrhythmias when used systemically; it is especially effective in the treatment of heart block in transplanted hearts. Knowing your strengths and weaknesses helps you to study more effectively. Take a PrepU Practice Quiz to find out how you measure up! ONLINE RESOURCES An extensive range of additional resources to enhance teaching and learning and to facilitate understanding of this chapter may be found online at the text’s accompanying website, located on thePoint at http://thepoint.lww.com. These include Watch and Learn videos, Concepts in Action animations, journal articles, review questions, case studies, discussion topics and quizzes. BIBLIOGRAPHY Farrell, M. & Dempsey, J. (2014). Smeltzer & Bare’s Textbook of Medical-Surgical Nursing (3rd edn). Sydney: Lippincott Williams & Wilkins. Goodman, L. S., Brunton, L. L., Chabner, B. & Knollmann, B. C. (2011). Goodman and Gilman’s Pharmacological Basis of Therapeutics (12th edn). New York: McGraw-Hill. Lim, A., Hussainy, S. & Abramson, M. J. (2013). Asthma drugs in pregnancy and lactation. Australian Prescriber, 36, 150–153. McKenna, L. (2012). Pharmacology Made Incredibly Easy (1st Australian and New Zealand edn). Sydney: Lippincott Williams & Wilkins. McKenna, L. & Mirkov, S. (2014). McKenna’s Drug Handbook for Nursing and Midwifery (7th edn). Sydney: Lippincott Williams & Wilkins. National Center for Complementary and Alternative Medicine. (2013). Herbs at a Glance: Ephedra. Available at: http://nccam. nih.gov/health/ephedra?nav=gsa. Porth, C. M. (2011). Essentials of Pathophysiology: Concepts of Altered Health States (3rd edn). Philadelphia: Lippincott Williams & Wilkins. Porth, C. M. (2009). Pathophysiology: Concepts of Altered Health States (8th edn). Philadelphia: Lippincott Williams & Wilkins. Vale, S., Smith, J. & Loh, R. (2012). Safe use of adrenaline autoinjectors. Australian Prescriber, 35, 56–58. Wilmot, L. A. (2010). Shock: Early recognition and management. Journal of Emergency Nursing, 36(2) , 134–139.

■■ Most of the b 2 -specific adrenergic agonists are used to manage and treat asthma, bronchospasm and other obstructive pulmonary diseases. ■■ Isoprenaline, a non-specific β -specific adrenergic agent, is used for its sympathomimetic effects to treat shock, cardiac standstill and certain arrhythmias when used systemically; it is especially effective in the treatment of heart block in transplanted hearts. ■■ Because of its many adverse effects, isoprenaline is reserved for use in emergency situations that do not respond to other, safer therapies. CHAPTER SUMMARY ■■ Adrenergic agonists, also called sympathomimetics, are drugs that mimic the effects of the sympathetic nervous system (SNS) and are used to stimulate the adrenergic receptors within the SNS. The adverse effects associated with these drugs are usually also a result of sympathetic stimulation. ■■ Adrenergic agonists include a - and b -adrenergic agonists, which stimulate both types of adrenergic ■ ■ Use minimal doses of isoprenaline needed to achieve desired effects to prevent adverse effects and maintain safety. ■ ■ Arrange for supportive care and comfort measures, including rest and environmental control, to relieve CNS effects ; provide analgesics for headache and safety measures if CNS effects occur to provide comfort and prevent injury ; and avoid overhydration to prevent pulmonary oedema. ■ ■ Provide thorough teaching, including drug name, dosage and frequency of administration; rationale for administration; monitoring required; anticipated adverse effects, measures to reduce these and warning signs of problems to report immediately. Evaluation ■ ■ Monitor response to the drug (improvement in condition being treated, stabilisation of blood pressure, prevention of preterm labour, cardiac stimulation). ■ ■ Monitor for adverse effects (GI upset, CNS changes, respiratory problems). ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, adverse effects to watch for and specific measures to reduce them). ■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen. KEY POINTS