McKenna's Pharmacology for Nursing, 2e

Learning objectives Upon completion of this chapter, you should be able to: 1. Outline the normal controls of blood pressure and explain how the various drugs used to treat hypertension or hypotension affect these controls. 2. Describe the therapeutic actions, indications, pharmacokinetics, contraindications, most common adverse reactions and important drug–drug interactions associated with drugs affecting blood pressure. 3. Discuss the use of drugs that affect blood pressure across the lifespan. 4. Compare and contrast the drugs captopril, losartan, diltiazem, nitroprusside and midodrine with other agents in their class and with other agents used to affect blood pressure. 5. Outline the care considerations, including important teaching points, for people receiving drugs used to affect blood pressure. 43 Drugs affecting blood pressure

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Glossary of key terms angiotensin-converting-enzyme (ACE) inhibitor: drug that blocks ACE, the enzyme responsible for converting angiotensin I to angiotensin II in the lungs; this blockage prevents the vasoconstriction and aldosterone release related to angiotensin II angiotensin II receptors: specific receptors found in blood vessels and in the adrenal gland that react with angiotensin II to cause vasoconstriction and release of aldosterone baroreceptor: pressure receptor; located in the arch of the aorta and in the carotid artery; responds to changes in pressure and influences the medulla to stimulate the sympathetic system to increase or decrease blood pressure cardiovascular centre: area of the medulla at which stimulation will activate the sympathetic nervous system to increase blood pressure, heart rate and so forth essential hypertension: sustained blood pressure above normal limits with no discernible underlying cause hypotension: sustained blood pressure that is lower than that required to adequately perfuse all of the body’s tissues peripheral resistance: force that resists the flow of blood through the vessels, mostly determined by the arterioles, which contract to increase resistance; important in determining overall blood pressure renin–angiotensin–aldosterone system: compensatory process that leads to increased blood pressure and blood volume to ensure perfusion of the kidneys; important in the continual regulation of blood pressure shock: severe hypotension that can lead to accumulation of waste products and cell death stroke volume: the amount of blood pumped out of the ventricle with each beat; important in determining blood pressure

ANTIHYPERTENSIVE AGENTS Angiotensin-converting- enzyme inhibitors

ramipril trandolapril Angiotensin II–receptor blockers candesartan

olmesartan telmisartan valsartan Calcium channel blockers amlodipine diltiazem

lercanidipine nifedipine verapamil Vasodilators diazoxide hydralazine minoxidil sodium nitroprusside

captopril enalapril fosinopril lisinopril perindopril quinapril

eprosartan irbesartan losartan

felodipine isradipine