Antihypertensives Flashcards
ACE inhibitors
Short term: Captopril
Long term: Lisinopril, Benazepril, Quinapril, Ramipril
Prodrug: Enalapril (converted to enalaprilat)
“Prils”
Mech: Block ACE,
Blocks breakdown of bradykinin (vasodilator)
Thera: Lower BP, CHRONIC RF, CHF, LV remodeling post-MI, LV hypertrophy, may reduce risk of diabetes
Tox: Cough (bradykinin), hypotension, decreased renal function, angioedema (rare)
Misc: Contraindicated in renal artery stenosis, hyperkalemia, ARF, pregnancy
Combined with thiazides or vasodilators due to the RAAS being stimulated in those states
Decreases TPR, Increases renin
Angiotensin Receptor Blocker
Losartan, Valsartan, Irbesartan
“Tans”
Mech: Competitive inhibitor of AII receptor in vascular endothelium
Thera: Lower BP, CHRONIC RF, CHF, LV remodeling post-MI, LV hypertrophy, may reduce risk of diabetes
Tox: Hypotension, decreased renal function, angioedema (rare)
Misc: Misc: Contraindicated in renal artery stenosis, hyperkalemia, ARF, pregnancy
Combined with thiazides or vasodilators due to the RAAS being stimulated in those states
Decreases TPR, Increases renin
Calcium Channel Blockers
Dihydropyridines: Amlodipine, Nifedipine (more potent)
Mech: Inhibit contraction of vascular smooth muscle by blocking calcium entry into the cell leading to reduced TPR (L-type voltage gated calcium channel)
Thera: Lower BP, Raynaud’s, Angina (vasodilate the coronary arteries)
Tox: Constipation, leg edema,
Misc: May worsen angina by increasing O2 demand (reflex tachy) however for most part no effect on HR, AV conduction, contractility so good for angina
Short acting worsen the effects
Contraindicated in decompensating heart failure, bradycardia, SA or AV node dysfunction
HR either, CO either, TPR decreases, intravascular volume increase, renin increases
Calcium Channel Blockers
Non-dihydropyridines: Diltiazem, Verapamil (more potent)
Mech: Inhibit contraction of vascular smooth muscle by blocking calcium entry into the cell leading to reduced TPR
(L-type voltage gated calcium channel)
Thera: Lower BP, Raynaud’s
Tox: Constipation, leg edema, CHF (negative inotropes), Bradycardia, AV node block
Misc: Short acting worsen the effects
Contraindicated in decompensating heart failure, bradycardia, SA or AV node dysfunction
HR either, CO either, TPR decreases, intravascular volume increase, renin increases
Propanolol
Class: Nonselective beta blocker
Mech: Blockage of B1 and B2 causing a decrease in cardiac output
Thera: Inferior in treatment of HTN and secondary outcomes of MI and CVA
Tox: Decreased exercise capacity, bronchospasm, bradycardia, CHF (negative inotrope), masks hypoglycemia, depression, worsening of peripheral vascular disease
Misc:
Decreases HR, CO, peripheral resistance, and renin
Increases fluid retention
Moderately selective beta blockers
Short acting: metoprolol and atenolol
Long acting: Nadolol and bisoprolol
Mech: Blocks B1 with very little B2 activity
Tox: Less likely to have the bronchospasm, masked hypoglycemia, and depression
Misc: Decreases HR, CO, peripheral resistance, and renin
Increases fluid retention
Carvedilol, labetalol
Mech: Blocks alpha and beta
Thera: Carvedilol=ACS or CHF
Labetolol=hypertensive urgency
Misc: Decreases peripheral resistance and renin
Increases fluid retention
Esmolol
Mech: Beta1 selective blocker
Thera: AV nodal blocking in unstable angina
Misc: short half-life
Alpha1 antagonists
Terazosin, doxazosin
Mech: Blocks peripheral a1 receptors reducing vascular resistance by blocking receptors on vascular smooth muscles
Thera: Lower BP, BPH
Tox: Orthostatic hypotension, fluid retention, worsening angina (reflex tachy)
Misc: Increase HR, CO, plasma volume
Decrease TPR
Arteriolar vasodilators
Hydralazine, minoxidil
Mech: Relax smooth muscles of peripheral arterioles
Thera: Minoxidil used for refractory hypertension and hair gain (Rogaine)
Hydralazine used for acute hypertensive urgency, CHF (when have both HTN and CHF)
Tox: Hydralazine=drug induced Lupus
Minoxidil=pericardial effusion, hirsuitism
Misc: Hydralazine serves as antioxidant preventing the oxidation of NO
Minoxidil causes vasodilation by opening CV ATP-dependent potassium channels
Increase HR, CO, intravascular fluid, renin
Decreases TPR
Central Acting sympathoplegic drugs
Clonidine and alpha-methyl DOPA
Mech: Stimulation of a2 adrenergic receptors reducing sympathetic outflow from vasomotor centers in the brainstem decreasing sympathetic tone
Thera: Methyl-alpha DOPA is used in pregnancy
Tox: Sedation, dry mouth, rebound hypertension if not weaned, fatigue, moderate orthostatic hypotension, depression
Misc: Increase intravascular volume
Decrease CO, HR, TPR, renin
Guanethidine
Class: Ganglion blocking agent
Mech: Block release of NE from post-ganglionic sympathetic nerve terminals
Thera: Reduce BP
Tox: Postural hypotension, diarrhea, ejaculation inhibition
Reserpine
Class: Ganglion blocking agent
Mech: Depletes NE, DA, 5-HT in CNS and PNS
Thera: Decreases CO and TPR
Tox: Sedation, depression, parkinsonism
