Snapshot A 44-year-old man presents to his primary care physician for an annual examination. He currently does not have any acute complaints. He has been attempting to increase the number of fruits and vegetables in his diet and has lost approximately 15 pounds over 6 months. His medical history is significant for type II diabetes mellitus and he is currently taking metformin. Physical examination is remarkable for a blood pressure of 155/103 mmHg and mildly decreased vibration and proprioception sense in his lower extremities. He returns to the clinic for two consecutive days to measure his blood pressure, which is 152/100 mmHg and 158/107 mmHg. He is started on lisinopril. Introduction Antihypertensive medications are used to manage hypertension in patients where conservative measures are ineffective there are four commonly used antihypertensive medications diuretics thiazides potassium-sparing diuretics sympatholytics β-blockers α-blockers vasodilators calcium channel blockers hydralazine minoxidil renin-angiotensin-aldosterone inhibitors angiotensin-converting enzyme (ACE) inhibitors angiotensin receptor blockers (ARBs) Diuretics Medications thiazides mechanism of action inhibits the NaCl transporter in the distal tubule vasodilation (mechanism is unclear) potassium-sparing diuretics mechanism of action promotes Na+ excretion in the distal nephron Sympatholytics Medications β-blockers mechanism decreases heart rate, which in turn, decreases cardiac output decreases renin release, which in turn, decreases total peripheral resistance notes can result in bronchospasm, impotence, and hyperglycemia e.g., metoprolol α-agonists mechanism central α2-agonist decreases the sympathetic outflow to blood vessels, heart, and kidneys by activating presynaptic α2-adrenoreceptors e.g., methyldopa and clonidine α-blockers mechanism α1-blockers blood vessel smooth muscle relaxation e.g., prazosin Vasodilators Medications hydralazine mechanism increases cGMP to cause direct vascular smooth muscle relaxation note this causes a reflex tachycardia; therefore, β-blockers are often given together minoxidil mechanism direct arteriolar smooth muscle relaxation calcium channel blockers mechanism decreases cardiac and vascular calcium influx, resulting in a decreased cardiac output and total vascular resistance Renin-Angiotensin-Aldosterone Inhibitors Medications angiotensin-converting enzyme (ACE) inhibitors mechanism inhibits ACE, which in turn, decreases circulating angiotensin II (AT-II) recall that AT-II causes vascular vasoconstriction increased aldosterone secretion from the adrenal gland (zona glomerulosa) notes decreases mortality in patients with acute myocardial infarction heart failure with decreased ejection fraction can result in a cough beneficial for patients with diabetes angiotensin receptor blockers (ARBs) mechanism directly blocks the AG-II receptor notes beneficial for patients with diabetes Antihypertensives in Pregnancy Medication options used to manage hypertension in pregnancy include hydralazine labetalol methyldopa nifedipine Antihypertensives in Hypertensive Emergencies Nitroprusside mechanism arteriole and venous dilation via cGMP notes is metabolized into cyanide, which can potentially lead to cyanide poisoning Fenoldopam mechanism a peripheral dopamine-1 receptor agonist notes maintains renal perfusion while the blood pressure is being decreased therefore, it is beneficial in patients with renal impairment Nicardipine and clevidipine mechanism decreases cardiac and vascular calcium influx Labetalol mechanism α- and β-blocker Antihypertensive Medications That Address Comorbid Conditions Individualizing Antihypertensive Therapy Condition Antihypertensive Medication Benign prostatic hyperplasia α-blockers Essential tremor β-blocker Hyperthyroidism β-blocker Migraine β-blocker Calcium channel blocker Osteoporosis Thiazide diuretics Raynaud phenomenon Dihydropyridine calcium channel blocker