Antihypertensives Flashcards
Hydrochlorothiazide: Brand name, others in class
HydroDiuril
Chlorthalidone, 5 others
Hydrochlorothiazide: Drug class
Pharmacologic: thiazide diuretic
Therapeutic: diuretic, antihypertensive
Hydrochlorothiazide: Pharmacodynamics (5)
Block reuptake of CL and NA fron tubular fluid after glomerular filtration
Appears to cause decrease in SVR via unclear mechanism
Lowers BP up to 10-15mmHg in many pts
Useful as monotherapy or in combinations
Chlorthaladone may be slightly better
Hydrochlorothiazide: Pharmacokinetics (5)
F ~70% Excreted unchanged in urine Short half life (hours) Not available in IV formulation Onset 2h, peak 5h, duration 10h
Hydrochlorothiazide: Toxicity (5)
Allergy to sulfa Abx Cause K and Mg depletion Cause Na and Cl depletion, metabolic alkalosis Volume depletion Worsen hyperuricemia
Hydrochlorothiazide: Interactions
Additive effects with most other antihypertensives
Hydrochlorothiazide: Special considerations (3)
More side effects in geriatric patients
Pregnancy Class D
Much less effective in pts with reduced GFR
Hydrochlorothiazide: Indications/dose/route (2)
12.5mg or 25mg po every morning
Little benefit, more toxicity when given in higher doses
Hydrochlorothiazide: Monitor (7)
BP, weight, edema, K, Mg, BUN, creatinine
Lisinopril: Brand name (2), others in class (3)
Prinivil, Zestril
Captopril, enalapril, ramipril (total of 10)
Lisinopril: Drug class (6)
Pharmacologic: ACE inhibitor
Therapeutic: antihypertensive, treatment of CHF, preserving renal function, preserving LV function after MI, acute management of MI
Lisinopril: Pharmacodynamics (2)
Inhibits conversion of AT I to AT II by ACE
Diminishes both vasoconstriction and stimulation of aldosterone secretion by AT II
Lisinopril: Pharmacokinetics (4)
Well absorbed
Onset 1h, peak 6h, duration 24hr
Once a day is fine
Excreted primarily in urine as unchanged drug
Lisinopril: Toxicity (5)
Orthostatic hypotension
Use with caution in pts with impaired renal function or RAS (dilates efferent arteriole!)
Caution in pts on diuretics or with aortic stenosis
Angioedema, cough
Acute renal failure
Lisinopril: Interactions (3)
Additive effects with most other antihypertensives
NSAIDs may reduce ability to lower BP
Hyperkalemia with KCl, others
Lisinopril: Special considerations (2)
Often discontinue diuretics prior to beginning use to reduce hypotension
Category C/D in pregnancy, abnormal cartilage development
Lisinopril: Indications/dose/route
Begin 10mg/day, titrate slowly up to 40mg/day max
Lisinopril: Monitor (6)
BP, weight, edema, K, BUN, creatinine
Losartan: Brand name
CoZaar
7 others in class
Losartan: Drug class (4)
Pharmacologic: angiotensin-1 receptor blocker (ARB)
Therapeutic: Antihypertensive, preserve renal function, treatment of CHF
Losartan: Pharmacodynamics
Block stimulation of ATI receptor by ATII, thereby reducing vasoconstriction and production of aldosterone
Losartan: Pharmacokinetics (4)
F ~30%
Onset 6h
Extensive first pass effect
Active metabolite 40x more potent, much longer half-life
Losartan: Toxicity (3)
Dizziness
Orthostatic hypotension
Worsening of renal failure
Losartan: Interactions
Additive effects with most other antihypertensives
Losartan: Special Considerations (2)
Pregnancy class C/D Use care in pts on diuretics, with RAS, or mitral or aortic stenosis
Losartan: Indications/dose/route
For HTN, daily doses 25-100mg q day
Losartan: Monitor (6)
BP, weight, edema, electrolytes, BUN, creatinine
Nitroprusside: brand name (2)
Nipride, Nitropress
Nitroprusside: Drug class (5)
Pharmacologic: vasodilator
Therapeutic: antihypertensive, management of severe CHF, management of pulmonary HTN, produce controlled hypotension to reduce bleeding during surgery
Nitroprusside: Pharmacodynamics (3)
Acts directly on vascular SM to cause dilation of both veins and arterioles
Metabolized to release CN- and NO, which -> guanylate cyclase -> production of cGMP from GTP -> vasodilation
cGMP then hydrolyzed to GMP by PDE
Nitroprusside: Pharmacokinetics (4)
Only route is IV
Rapid onset and cessation (minutes) -> minute-to-minute titration
CN- metabolite converted to SCN in liver, then excreted in urine
Must be given by continuous infusion, no longer than 24 hours
Nitroprusside: Toxicity (4)
Excessive hypotension
Accumulation of CN- and thiocyanate
Headache
Decreased blood flow to brain
Nitroprusside: Interactions
Additive effects with most other antihypertensives
Nitroprusside: Special considerations (3)
Monitor pts VERY closely - must be in ICU with arterial line, no longer than 24 hrs
Avoid high infusion rates or prolonged infusions to prevent accumulation of CN-
Use caution in pts with increased intracranial pressure
Nitroprusside: Indications/dose/route
For treatment of hypertensive crisis, given as IV infusion at 0.3-10mcg/kg/min, NO longer than 24 hours
Nitroprusside: Monitor (4)
BP, HR, metabolic acidosis
Most often requires arterial line
Hydralazine: Brand name
Apresoline
Hydralazine: Drug class (4)
Pharmacologic: peripheral vasodilator
Therapeutic: antihypertensive, treatment of CHF, vasodilator
Hydralazine: Pharmacodynamics (3)
Direct acting vasodilator
Induces endothelium to produce NO (different from nitroprusside), which then -> to SM cells and -> production of cGMP
Minimal venodilating effect
Hydralazine: Pharmacokinetics (6)
Given po, im, iv
Metabolized extensively in GI mucosa and in liver
Eventually excreted as metabolites in urine
F ~40%
Onset 30 after po dose, 10 min after iv dose
Persist for 2-6 hours
Hydralazine: Toxicity (2)
More dangerous in pts with renal disease, prior stroke, angina
Watch for hypotension, edema, occasionally drug-induced lupus
Hydralazine: Interactions
Additive effects with most other antihypertensives
Hydralazine: Special considerations (2)
Never use as chronic oral monotherapy for treatment of HTN, will -> edema, reflex tachycardia (rarely used today except for final month of pregnancy with extreme HTN)
Concern giving to patients with CAD
Hydralazine: Indications/dose/route
Dose 10-50 mg po 4x/day
Hydralazine: Monitor (6)
BP, weight, edema, BUN, creatinine, symptoms of lupus or angina
Verapamil: Brand name (2), others in class (4)
Isoptin, Calan
Others: nifedipine, amlodipine, diltiazem, nicardipine (total 8)
Verapamil: Drug class (3)
Pharmacologic: Ca entry blocker
Therapeutic: antihypertensive, antianginal, antiarrhythmic
Verapamil: Pharmacodynamics (5)
Reduces BP by inhibiting influx of Ca through slow channels, -> dilating peripheral arterioles
Produces negative inotropic effect
**Angina: reduces afterload, decreasing oxygen consumption
Inhibits spasm of coronary arteries in vasospastic angina
Blocks reentry paths through AV nodes in paroxysmal SVT
Verapamil: Pharmacokinetics (6)
Absorbed rapidly, but F ~30% Also available in SR tablets Cleared by kidney and liver (produces active metabolites Onset 2h po, 1-5 min IV Half life 6-12h May be given po or IV
Verapamil: Toxicity (4)
Hypotension, AV block, worsening of CHF, bradycardia
Verapamil: Interactions (2)
Additive effects with most other antihypertensives
Additive toxic effects on heart when given with beta-blockers
Verapamil: Special considerations (3)
Use reduced dose in pts with both renal and hepatic disease
Short-acting nifedipine (and similar CEBs) can increase risk of MI
Pregnancy C
Verapamil: Indications/dose/route
80 mg 3x/day, or 240mg SR once daily
Verapamil: Monitor (3)
Weight, edema, BP
Clonidine: Brand name, others in class (1)
Catapres
Other: Methyldopa
Clonidine: Drug class (3)
Pharmacologic: central alpha-2 agonist
Therapeutic: antihypertensive, adjunct to Rx of opioid withdrawal, prophylaxis of migraine
Clonidine: Pharmacodynamics
Stimulates alpha-2 adrenoceptors in brainstem -> down-regulation of sympathetic output
Clonidine: Pharmacokinetics (3)
Onset 1h, duration 8h
F ~ 85%
Also available as cutaneous patch
Clonidine: Toxicity (3)
Withdraw gradually because of risk of rebound HTN
Risk of bradycardia in sinus node disease
Lethargy, fatigue, depression
Clonidine: Interactions (2)
Additive effects with most other antihypertensives
Additive sedation with other CNS drugs
Clonidine: Special Considerations (2)
Pregnancy class C Avoid in pts with renal insufficiency
Clonidine: Indications/dose/route
Begin with 0.1mg po bid, up to 1.2mg per day
Transdermal: begin with 0.1mg per 24 hr as a 7 day patch
Clonidine: Monitor (3)
BP, HR, fatigue
Trimethaphan: Brand name, others in class
Arfonad
No others in class
Trimethaphan: Drug class
Pharmacologic: ganglionic transmission blocker
Therapeutic: antihypertensive (acute, by IV)
Trimethaphan: Pharmacodynamics (2)
Blocks nicotinic transmission within both sympathetic and parasympathetic ganglia (Nn receptors)
Produces veno- and vasodilatation
Trimethaphan: Pharmacokinetics (3)
Useful only when given IV
Produces fall in BP within minutes
Partly metabolized, partly excreted by kidneys
Trimethaphan: Toxicity (3)
Watch for sudden, severe drop in BP
Fall in HR
Reduction in just about any sympathetic or parasympathetic response
Trimethaphan: Interactions
Additive effects with most other antihypertensives
Trimethaphan: Special considerations (2)
Pts miserable, only used during general anesthesia
Helps to tilt pt to help control BP
Trimethaphan: Indications/dose/route
Give by IV infusion to treat HTN crisis, or for controlled hypotension during cardiovascular surgery
Trimethaphan: Monitor (2)
Minute to minute monitoring of BP and HR
Reserpine: Brand name, others in class
No brand name
Reserpine: Drug class
Pharmacologic: Rauwolfia alkaloid
Therapeutic: Antihypertensive
Reserpine: Pharmacodynamics (3)
Binds to vesicles that contain NE OR serotonin, preventing their uptake and depleting the neuron of NE or serotonin
Takes 2-3 weeks to deplete
Includes neurons and the adrenal medulla
Reserpine: Pharmacokinetics
Good oral bioavailability, but biologic effects take 2-3 weeks (slow depletion of NE/serotonin from vesicles)
Reserpine: Toxicity (3)
Dizziness
Orthostatic hypotension
Depression!!! (NOT used today!)
Reserpine: Interactions
Additive effects with most other antihypertensives
Reserpine: Special considerations (2)
FDA approved in 1953
First antihypertensive drug + first sympatholytic drug approved
Reserpine: Indications/dose/route
For HTN, 0.1-0.2mg po qd
Reserpine: Monitor (3)
BP, sympathetic tone, depression
Atenolol: Brand name, others in class (2)
Tenormin
Others: Propranolol, metoprolol (Toprol XL)
Atenolol: Drug class (4)
Pharmacologic: beta-adrenoceptor blocker (beta-1 specific)
Therapeutic: antihypertensive, antiarrhythmic, primary and secondary prevention of MI, anti-anginal
Atenolol: Pharmacodynamics (2)
Binds directly to beta-receptors (beta-1»_space; beta-2) -> lower BP via several mechanisms (lower CO, lower RAAS activation)
Less effective in preventing strokes than other drugs, so used less often as initial monotherapy
Atenolol: Pharmacokinetics (5)
Available po or IV Variable oral F Onset 1-2h, duration 12-24h Can be given once per day Renally excreted (longer half life)
Atenolol: Toxicity (4)
Excessive hypotension
Bradycardia
Heart block can worsen CHF if severe (but good for mild to moderate CHF)
Worsen bronchospasm in severe asthmatics
Atenolol: Interactions (2)
Additive effects with most other antihypertensives
Additive AV block with CEBs
Atenolol: Special considerations (3)
May be especially useful in HTN pts with exertional angina, MI, a. fib
Watch out for abrupt withdrawal
No longer first line drug unless other indications exist
Atenolol: Indications/dose/route
For treatment of HTN, 25-100 mg per day, in one or two doses
Atenolol: Monitoring (3)
BP, HR, exercise tolerance
Prazosin: Brand name, others in class (3)
Minipress
Terazosin, doxazosin, tamsulosin
Prazosin: Drug class (4)
Pharmacologic: alpha-1 adrenoceptor blocker
Therapeutic: Antihypertensive, treatment of BPH, treatment of Raynaud’s syndrome, treatment for kidney stones
Prazosin: Pharmacodynamics
Blocks alpha-1 receptors on arterioles and veins, thereby inhibiting NE-mediated vasoconstriction and venoconstriction
Prazosin: Pharmacokinetics (4)
Available po or transdermal
Variable oral bioavailability (~60%)
Onset 2h, duration 12-24h
Extensively metabolized in liver
Prazosin: Toxicity (3)
Excessive hypotension with passing out, especially orthostatic, especially in pts on diuretics
Prazosin: Interactions
Additive effects with most other antihypertensives, especially diuretics
Prazosin: Special considerations (2)
Start gradually at bedtime to avoid first-time passing out
Male pts with BPH?
Prazosin: Indications/dose/route
As monotherapy, begin with 1mg tid, advance to 20mg per day divided tid
Prazosin: Monitor (3)
BP, weight, edema
Labetalol: Brand name, others in class
Trandate
Others (KNOW): Carvedilol/Coreg(tm)
Labetalol: Drug class (2)
Pharmacologic: Alpha and beta receptor blocker
Therapeutic: Antihypertensive, treatment of CHF
Labetalol: Pharmacodynamics (2)
Reduces BP by blocking access of NE to beta-receptors and alpha-1 receptors -> lowering BP by several different mechanisms
Pts differ in degree of beta- vs alpha-blockade
Labetalol: Pharmacokinetics (3)
Excellent absorption but high first pass effects (F~25%)
Onset 1-2h po, 2-5min IV
Extensively metabolized in liver by IID6
Labetalol: Toxicity (3)
Avoid in pts with bradycardia, heartblock, CHF, asthma, shock Use caution in pts with cardiomyopathy, pheochromocytoma Pregnancy class D
Labetalol: Interactions
Additive effects with most other antihypertensives
Labetalol: Special considerations (3)
Use reduced doses in pts with impaired liver function
Dizziness is most troubling early side effect
Most often used for hypertensive crisis (as with nitroprusside)
Labetalol: Indications/dose/route (2)
Most commonly given IV with initial small boluses of 20mg, followed by continuous infusion at 2mg/min
Not usually given po for chronic treatment (80mg tid or 240mg SR qd)
Labetalol: Monitor (2)
BP, HR