Snapshot A 54-year-old man presents to his primary care physician for an annual examination. In his previous visit, he was diagnosed with hypertension. In today's visit, his blood pressure has not improved given his difficulty to adhere to a diet with more fruits and vegetables and exercise. 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 152/99 mmHg and mildly decreased vibration and proprioception sense in his lower extremities. 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) direct renin inhibitors 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 Note that loop diuretic abuse can result in an increased sodium and potassium level in the urine Sympatholytics Medications β-blockers mechanism decreases heart rate, which decreases cardiac output decreases renin release, which decreases total peripheral resistance notes can result in bronchospasm, impotence, and hypoglycemia can cause Raynaud phenomenon treat with dihydropyridine calcium channel blocker e.g., metoprolol α-blockers mechanism central α2-agonists decreases the sympathetic outflow to blood vessels, heart, and kidneys e.g., methyldopa and clonidine α1-blockers blood vessel smooth muscle relaxation e.g., prazosin and terazosin 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 can result in peripheral edema treat with ACE inhibitors, changing the CCB, or changing the dose Renin-Angiotensin-Aldosterone Inhibitors Medications angiotensin-converting enzyme (ACE) inhibitors mechanism inhibits ACE, which decreases circulating angiotensin II (ATII) recall that ATII 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 arteriolar 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 TherapyConditionAntihypertensive MedicationBenign prostatic hyperplasiaα-blockersEssential tremorβ-blockerHyperthyroidismβ-blockerMigraineβ-blockerCalcium channel blockerOsteoporosisThiazide diureticsRaynaud phenomenonDihydropyridine calcium channel blocker