Anti-hypertensive drugs Flashcards
what are the stages of hypertension
normal 160 or >100
8 classes of drugs that can be used to treat HTN
*Diuretics
*Calcium Channel Blockers (CCBs)
Centrally-acting Agents
Alpha Adrenergic Blockers
Beta Adrenergic Blockers (BBs)
Vasodilators
*Angiotensin Converting Enzyme inhibitors (ACEIs)
*Angiotensin Receptor Blockers (ARBs)
what are the 4 sites of action for HTN drugs
- arterioles (resistance)
- venules (capacitance)
- Heart (pump output)
- Kidneys (volume)
when is diuretics use
*Drugs of choice in uncomplicated hypertension
Effective for mild-moderate hypertension combined with lifestyle modifications
Generics most economical choice
Thiazide diuretics MOA and examples
Hydrochlorothiazide, Chlorthalidone
Mode of Action (MOA) – inhibits Na+/Cl co-transporter
Initial volume contraction
later decreased in peripheral resistance (prostaglandin)
Mild Na+ excretory effect
Thiazide Diuretics side effects
Hyponatremia
Hyperglycemia
Increased LDL/HDL
Hypokalemia
mechanism of hypokalemia and metabolic alkalosis with thiazide diurects
Low plasma Na+ stimulates aldosterone -acts in collecting duct cells
Increased delivery of Na+ to collecting duct cells increases Na+ diffusion
K+ loss from principal cells and H+ loss from intercalated cells due to resulting neg. charge on lumen side
good drug combinations with thiazide diuretics
Combined with BBs, ACEIs, ARBs and centrally acting anti- hypertensive
drug interactions with thiazide diuretics
NSAIDS Beta Blockers (can use but be cautious)
contraindications for thiazide diurectics
Hypokalemia and pregnancy (as a new therapy)
thiazide diurectis are less effective in which pts
pts with renal insufficiency
Loop diurectics MOA and example
furosemide (lasix)
MOA – blocks Na+/K+/Cl co-transporter, causes venous dilation via prostaglandins
side effects of loop diurectics
Dehydration/hyponatremia Hypokalemia Impaired diabetes control Increased LDL/HDL Ototoxicity
loop diurectics drug interactions
NSAIDS
Aminoglycosides (increased ototoxicity)
Potassium Sparing Diuretics examples
spironolactone and eplerenone, triamterene, amiloride
Potassium Sparing diuretics MOA
Aldosterone receptor blocker – combine with diuretics, not used for monotherapy of HT**
side effects of Potassium sparing diuretics
hyperkalemia
gynecomastia (spironolactone)
drug interactions of K+ sparing diuretics
NSAIDS
ACE inhibitors
ARBs
contraindications for K+ sparing diuretics
RAS inhibitors (ACEI and ARB)
Potassium sparing diuretics are commonly given with
thiazide and loop diuretics to prevent hypokalemia (excretion of K+)
Calcium channel blockers MOA
All reduce vascular resistance by reducing calcium influx in VSM
Non-dihydropyridines also reduce pacemaker potentials, AV node conduction, and contractility
what are the 3 Ca channel blockers
Nifedipine
Diltiazem
Verapamil
side effects of Nifedipine
(dihydropyridine) acute tachycardia and peripheral edema
side effects of diltiazem
(non-dihydropyridine) bradycardia
side effects of verapamil
(non-dihydropyridine)
constipation
bradycardia
Non-dihydropyridines Ca Channel blockers are contraindicated in which pts
pts with conduction disterbances
or in uncompensated heart failure (cardiogenic shock)
Clonidine and Guanfacine MOA
α2-adrenergic receptor agonist in medullary cardiovascular center decreases sympathetic outflow from CNS
Clonidine side effects and drug interactions
SE: sedation (12-35%), dry mouth (25-40%), bradycardia, dermatitis
Caution pt about missing doses withdraw slowly to prevent rebound hypertension
Drug interactions : CNS depressants
advantages of Guanfacine over clonidine
longer half life and less risk of rebound
Methyldopa MOA
converted to methylnorepinephrine
α2-adrenergic receptor agonist (same MOA as clonidine)
Competes with L-DOPA for DOPA decarboxylase (inhibits dopamine production) (do not give to someone with parkinsons)
Methyldopa side effects and drug interactions
drug interactions levodopa, SE: sedation
Methyldopa clinical use
anti-hypertensive during pregnancy
Reserpine MOA
blocks VMAT vesicular transporter, prevents storage of NE centrally and peripherally.
used with diuretics for mild and moderate hypertension
Reserpine side effects
depression (crosses BBB), nasal congestion
Alpha Adrenergic Receptor Antagonists examples and MOA
Phenoxybenzamine, Prazosin, terazosis and doxazosin
block α-adrenergic-mediated vasoconstriction at receptor
Phenoxybenzamine use and side effect
phenoxybenzamine is non-selective, primarily used in pheochromocytoma, SE- tachycardia
prazosin, terazosis, doxazosin MOA and side effects
selective α1-adrenergic antagonist,
less tachycardia than direct vasodilators, hypotension w/ 1st dose
terazosin and doxazosin have longer half lifes
Beta-Adrenergic Antagonists MOA
MOA – decreased cardiac contractility and CO, decreased renin secretion and thus decreased Angiotensin II production
Non selective Beta-Adrenergic Antagonists
Propranolol
Nadolol (longer half-life)
Pindolol (partial agonist, less bradycardia)
Carvedilol (alpha receptor antagonist, vasodilator)
cardioselective/B1-selective B-Blockers
Metoprolol (lipophilic)
Atenolol
Labetolol (lipophilic)
side effects of Beta Blockers
Bradycardia Increased triglycerides Decreased HDLs Hyperglycemia Impaired exercise tolerance
Non-selective
Increased airway resistance
Lipophilic
Insomnia
chronic fatigue
Drug Interactions with Beta blockers
CCBs (reduced contractility and conduction)
contraindications for beta blockers
Cardiogenic Shock
Sinus bradycardia
Asthma
Severe heart failure
Beta blocker consideration in pts with diabetes
Can mask and prolong insulin-induced hypoglycemia
Vasodilators examples and MOA
Hydralazine
Minoxidil
Nitroprusside
vasodilation of small vessels, primarily arterioles
when do you use vasodilators such as Hydralazine
Minoxidil, and Nitroprusside?
drug resistant hypertension and emergencies
Nitroprusside side effect
cyanide poisoning
Hydralazine and Minoxidil
tachycardia, angina aggravation, fluid retention, NSAIDS can reduce effectiveness
ACEI MOA
blocks production of Angiotensin II and Ang II-mediated- vasoconstriction
ACEI examples
Captopril (short half life)
Enalapril (converted to active metabolite, longer half-life)
Lisiniopril
ACEI side effects
hyperkalemia, rash, dry cough, angioedema (0.2%)
ACEI drug interactions
Exacerbates hyperkalemic effect of K+ sparing drugs (no aldosterone = decreased K+ excretion)
ACEI contraindications
pregnancy, bilateral renal stenosis
benefits of ACEI
Prolongs survival in pts with HF or LV dysfunction after MI
Preserves renal function in diabetic patients
*Angiotensin II Receptor Blockers (ARBs) example
Losartan
Side effect of ARB
hyperkalemia (no aldosterone = decreased K+ excretion)
contraindications of ARBs
Pregnancy
Drug interactions of ARBs
K+ sparing drugs
with ARBs it is better to use them with what other type of drug rather than increase their dose
diuretics
thiazide diuretics work well with which other types of drugs for hypertension control
K+ sparing diuretics and BB
K+ sparing diurects work well with which other types of drugs for hypertension control
thiazide or loop diuretics
Calcium channel blockers work well with what other class of drug
ACEI
ACEI cause hyperkalemia when used with what other durg
K+ sparing diuretics
why would you not combine ACEI and ARBs in diabetics
no advantage and increases risk of hyperkalemia
what is the first choice drug in diabetic patients?
ACEIs - delay loss of renal function
CCBs (few effects on carb metabolism)
What is the first choice drug in heart failure patients
ACEI (reduce mortality) combination with diuretics for congestion
what are best choices for MI pts
ACEI (reduce remodeling) and BB (reduce arrhythmia and remolding)
what drugs must be avoided in pregnancy
ACEI and ARBs and BB (inhibit renin)
what is the drug of choice in pregnancy
methyldopa
which drugs are less effective in african americans
BB, ACEI (but work well when combined with diuretics)
which drugs are most efficacious in African americans
monotherapy with diuretics (CCB are best)
what considerations should be take for elderly patients
smaller doses with small increments
simple regimens
monitor side effects closely
what drugs should be avoided in pts with obstructive airway disease
avoid BB