McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 5 9 Antiemetic agents

exposure to the sun and ultraviolet light. Sunscreens and protective clothing are essential if exposure cannot be prevented.

■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen. ■ ■ Evaluate the effectiveness of the teaching plan (person can name the drug and dosage, as well as describe adverse effects to watch for and specific measures to avoid them).

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ONLINE RESOURCES

KEY POINTS

■■ Antiemetics are used to manage nausea and vomiting in situations in which these actions are not beneficial and could cause harm to the person. ■■ Antiemetics act by depressing the hyperactive vomiting reflex, either locally or through alteration of CNS actions. ■■ The choice of an antiemetic depends on the cause of the nausea and vomiting, and the expected actions of the drug. ■■ Antiemetics include the phenothiazines and centrally acting non-phenothiazine metoclopramide; anticholinergic/antihistamines; the 5-HT 3 receptor blockers; and the newest class of antiemetic, the substance P/neurokinin 1 receptor antagonists. ■■ Phenothiazines and the non-phenothiazine metoclopramide are used as antiemetics to depress the CNS, including the CTZ. People must be monitored for CNS depression. Photosensitivity and pink to red-brown colour of the urine are common adverse effects of these drugs. ■■ Anticholinergic/antihistamine drugs are used to block the transmission of impulses within the CNS. They may be particularly effective in treating motion sickness. People receiving these drugs must be monitored for parasympathetic blocking effects, drowsiness and sedation. ■■ The 5-HT 3 blockers are newer antiemetics that directly block specific receptors in the CTZ to prevent nausea and vomiting. They are used in cases of nausea and vomiting associated with antineoplastic chemotherapy and radiation therapy as well as postoperative nausea and vomiting. ■■ Most antiemetics cause some CNS depression, with resultant dizziness, drowsiness and weakness. Care must be taken to protect the person and advise them to avoid dangerous situations. ■■ Photosensitivity is another common adverse effect with antiemetics. People should be protected from

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BIBLIOGRAPHY

Barrett, K. E. & Ganong, W. F. (2010). Ganong’s Review of Medical Physiology (23rd edn). New York: McGraw-Hill. Forbes, D. & Fairbrother, S. (2008). Cyclic nausea and vomiting in childhood. Australian Family Physician, 27(1–2) , 33–36. Goel, R. & Wilkinson, M. (2013). Recommended assessment and treatment of nausea and vomiting. Prescriber, 24(3) , 23–27. 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. Graudins, L. V. (2009). Preventing motion sickness in children. Australian Prescriber, 32 , 61–63. Gutierrez-Williams, G. & Goldman, M. (2008). Cost effective management of postoperative vomiting. Connecticut Medicine, 72(1) , 21–24. Kelly, B. & Ward, K. (2013). Nausea and vomiting in palliative care. Nursing Times, 109(39) , 16–19. Kerr, C. L. (2008). What goes in must come out. Journal of Paediatric Health Care , 22(1) , 44–48. Kovac, A. (2013). Update on the management of postoperative nausea and vomiting. Drugs , 73(14) , 1525–1547. 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. Middleton, J. & Lennan, E. (2011). Managing chemotherapy- induced nausea and vomiting. British Journal of Nursing, 22 (supp), S7–S15. 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. Raymond, S. H. (2013). A survey of prescribing for the management of nausea and vomiting in pregnancy in Australia. Australian and New Zealand Journal of Obstetrics and Gynaecology, 53 , 358–362.

CHAPTER SUMMARY