Drugs Affecting Blood Pressure PDF

Drugs Affecting Blood Pressure Chapter 43  Elements Determining Blood Pressure ▪ Heart Rate ▪ Stroke Volume / Cardiac Output ▪ Amount of blood that is pumped out of the ventricle with each heartbeat. Cardiac OP is HR x SV ▪ Total Peripheral V...

Drugs Affecting Blood Pressure Chapter 43  Elements Determining Blood Pressure ▪ Heart Rate ▪ Stroke Volume / Cardiac Output ▪ Amount of blood that is pumped out of the ventricle with each heartbeat. Cardiac OP is HR x SV ▪ Total Peripheral Vascular Resistance ▪ Resistance of the muscular arteries to the blood being pumped through ▪ MAP = CO x PVR ▪ Most hypertension is Primary Idiopathic Hypertension (Essential) ▪ Secondary Hypertension may have a cause that can be treated Conditions Related to Untreated Hypertension ▪ Coronary Artery Disease ▪ Heart Attack ▪ Heart Failure ▪ Stroke ▪ Renal Failure ▪ Loss of Vision ▪ Peripheral Vascular Disease ▪ Aortic Aneurysm  Risks for Coronary Artery Disease Related to Hypertension ▪ Thickening of the heart muscle ▪ Increased pressure generated by the muscle on contraction ▪ Increased workload on the heart Systolic, Diastolic Blood Pressure ACC/AHA (mm Hg) metoprolol ▪ →  heart contractility (inotropic) > propranolol ▪ →  rate of conduction thru AV node > atenolol ▪ Uses > nadolol ▪ Primary hypertension ▪ Angina, some dysrhythmias, MI ▪ Special beta blockers for CHF (bisoprolol, carvedilol, nebivolol, ER metoprolol) ▪ Other uses: ▪ Hyperthyroidism, migraines, stage fright, test anxiety, pheochromocytoma, glaucoma ▪ Contraindications for Beta Blockers ▪ Bradycardia ▪ Heart block ▪ Cardiogenic shock ▪ Diabetes ▪ Pregnancy / lactations ▪ Caution with resp. disorders, thyroid disorders, PVD  Beta-Adrenergic Blockers ▪ Adverse Effects: R/T Blocking Beta 1 Effects ▪ Bradycardia (don’t give if pulse < 60/min) (teach pt. to monitor pulse and BP) ▪  cardiac output (caution with heart failure) (avoid non-selective blockers in pt. with heart failure) ▪ AV block (monitor, EKG) ▪ Orthostatic hypotension (cautions, safety) ▪ Rebound myocardium excitation with D/C (don’t D/C abruptly, D/C over 1-2 weeks) ▪ R/T Blocking Beta 2 Effects (non-selective agents) ▪ Bronchoconstriction (avoid in asthmatics) ▪ Inhibition of glycogenolysis (caution with DM) ▪ Take at bedtime to  “first dose” hypotensive effect  Alpha-Beta Adrenergic Blockers Carvedilol Labetalol ▪ Sympatholytic ▪ Powerful @ Block both alpha and beta receptors ▪ used with other agents ▪ Limited use because of side effects (fatigue, sexual dysfunction, insomnia, GI / GU disturbances)  Alpha1 Adrenergic Blockers ▪ Action: ▪ sympatholytic ▪ Block alpha1 action ▪ → venous and arterial dilation ▪ → smooth muscle relaxation in prostate / bladder neck ▪ Uses: ▪ Primary hypertension ▪  symptoms of BPH (urgency, frequency, dysuria) ▪ Contraindications / Cautions doxazosin ▪ Pregnancy / lactation prazosin ▪ Nursing Considerations terazosin ▪ Obtain baseline VS ▪ Take at bedtime to  “first dose” hypotensive effect  Centrally-Acting Alpha2-Adrenergic Agonists Action: ▪ Act in CNS to block stimulation of alpha and beta adrenergic receptors in the heart and vascular system  sympathetic stimulation of myocardium → bradycardia,  cardiac output  sympathetic stimulation of peripheral blood vessels Clonidine → vasodilation →  BP Methyldopa Uses ▪ Primary hypertension ▪ Severe cancer pain (epidural) ▪ Investigational uses (migraines, Tourettes, ADHD, substance withdrawal symptoms, menopause S/S) Contraindications / Cautions ▪ Clonidine / Pregnancy Category C / Lactation ▪ Those taking anticoagulants ▪ Caution with various chronic illnesses ▪ Rebound hypertension with abrupt D/C (D/C slowly)  Question 4 Which of the following is a side effect of clonidine that usually diminishes with time? a) Excessive saliva b) Bradycardia c) Sedation d) Pruritis  Question 5 Because of it’s beta-adrenergic blocking effects, patients with which of the following disorders should be especially cautious when using beta blockers? a) COPD b) Migraine headaches c) Sensorineural deafness d) Insulin-dependent diabetes  Treatment of HYPOTENSION Situations in Which Hypotensive States Can Occur ▪ Heart muscle is damaged and unable to pump effectively ▪ Severe blood loss, volume drops dramatically ▪ Extreme stress when body’s levels of norepinephrine are depleted ▪ Body is unable to respond to stimuli to raise blood pressure  Agents to Treat Hypotension ▪ Sympathetic Adrenergic Agonists ▪ (Sympathomimetics) ▪ Dobutamine ▪ Dopamine ▪ Ephedrine ▪ Epinephrine ▪ Isoproterenol (Isuprel) ▪ Metaraminol ▪ Norepinephrine (Levophed) ▪ Phenylephrine ▪ Alpha-Specific Adrenergic agonist Agent ▪ Midodrine  Agents to Treat Hypotension ▪ Alpha Specific Adrenergic Agent ▪ Midodrine ▪ Sympathomimetic ▪ Activates alpha-receptors in arteries and veins to produce an increase in vascular tone and an increase in blood pressure ▪ Indications Symptomatic treatment of orthostatic hypotension ▪ Contraindications Supine hypertension, CAD, pheochromocytoma, and with urinary retention  Midodrine ▪ Caution ▪ Pregnancy and lactation ▪ Visual problems ▪ Adverse Effects ▪ Related to stimulation of alpha-receptors ▪ Drug-to-Drug Interactions ▪ Cardiac glycosides, beta blockers, alpha-adrenergic agents, and corticosteroids  Question 6 You are caring for a 27-year-old African American woman who was just prescribed an ACE inhibitor for management of her hypertension. What should you advise this patient about contraception? a. The use of spermicidal jellies is recommended. b. The minipill is the contraception method of choice. c. Use barrier contraceptives to prevent pregnancy while taking these drugs. d. No special precautions need to be taken.