First and Second line drugs for HTN

Thiazide Diuretics

Proto: Hydrochlorothiazide [HCTZ]

1st line

MOA: ↑ sodium and water excretion in the distal tubule → ↓ BP

ADR: HypoK+/Na+, dehydration, hyperuricemia; ↑ BS

Watch for weakness, confusion, muscle cramps, or dysrhythmias

ACE inhibitors

Proto: Captopril (lisinopril used more frequently)

1st line

MOA: ↓ angiotensin II and aldosterone → vasodilation and ↓ sodium retention

ADRs: Dry cough, hyperkalemia, hypotension; angioedema, teratogenic

Facial or tongue swelling → airway emergency

If cough develops → switch to an ARB

ARBs

Proto: Losartan

1st line

MOA: Blocks ang II receptors → vasodilation and dec aldosterone effect

ADRs: Hyperkalemia, hypotension, dizziness, teratogenic

Watch for K+ and kidney fcn

Note: cannot be used w/ ACEIs b/c they work on the same pathway

Dihydropyridine (DHP) Calcium channel blockers (CCBS)

Proto: Nifedipine ER

1st line

MOA: relaxes arterial smooth muscle → vasodilation → ↓ vascular resistance and BP

ADRs: peripheral edema, flushing, dizziness, reflex tachycardia

Do not crush

Non-Dihydropyridine CCBs

Proto: verapamil

1st line

MOA: Slows HR and AV conduction; vasodilation

ADR: Bradycardia, hypotension, constipation, AV block

Review HF and other cardiac meds b/4 administering

Good for irregular heartbeats

Beta blockers

Atenolol (β₁-selective prototype), propranolol (nonselective)

2nd line

MOA: ↓ HR and contractility → ↓ CO and BP

ADRs: Bradycardia, fatigue, dizziness, hypotension

Can mask tachycardia during hypoglycemia

Aldosterone antagonists

Proto: Spironolactone

2nd line

MOA: Blocks aldosterone → ↑ sodium and water excretion while retaining K⁺

ADR: Hyperkalemia, hypotension, gynecomastia

Monitor K+ and supplements; risk rises with CKD or an ACE inhibitor/ARB

Direct Vasodilators

Proto: Hydralazine

MOA: Relaxes arteriolar smooth muscle → ↓ SVR

2nd line

ADR: Reflex tachycardia, fluid retention, headache; possible lupus-like syndrome

Watch for new fever and onset joint pain

Fast acting → fall risk → caution w older adults

Alpha 1 blocker

Proto: prazosin

MOA: Blocks vascular α₁ receptors → vasodilation → ↓ BP

2nd line; helps w BPH

ADR: Orthostatic hypotension, dizziness, first-dose syncope

Get up slowly after taking; follow bedtime dose as prescribed; 1st dose = greatest risk

Direct renin inhibitors

Proto: Aliskiren

2nd line

MOA: Inhibits renin → ↓ angiotensin I and II formation → ↓ BP

ADR: Diarrhea, hyperkalemia, hypotension; angioedema, teratogenic

Do not combine with an ACE inhibitor or ARB in a patient with diabetes

Emergency IV vasodilator

Proto: Sodium nitroprusside

MOA: Rapidly relaxes arteries and veins → rapid ↓ BP

Used in hypertensive emergencies

ADR: Excessive hypotension; cyanide or thiocyanate toxicity

Infuse too fast → ischemia; MUST TITRATE AND GIVE SLOWLY

Continuous BP monitoring (A-line)