Anti-hypertensive Drugs Flashcards
What is the average efficacy of diuretics’ ability to lower blood pressure when administered alone
about 10-15 mmHg
In what context of hypertension are diuretics used for
mild to moderate hypertension with normal cardiac/renal function
In what patients are the thiazides not particularly effective
patients with renal insufficiency
What are the 8 classes of drugs used to treat hypertension
- Diuretics
- Calcium channel blockers (CCBs)
- Centrally acting agents
- Alpha adrenergic blockers
- Beta adrenergic blockers
- Vasodilators
- Angiotensin converting enzyme inhibitor (ACE-I)
- Angiotensin receptor blockers (ARBs)
Of the 8 classes of drugs used to treat hypertension which 4 are considered to be the first line drugs of choice
- Diuretics
- CCBs
- ACE-Is
- ARBs
generally (not including the K+ sparing diuretics) what are the side effects of the diuretics
Hyponatremia, HYPERGLYCEMIA, Increased LDL/HDL ratio, HYPOKALEMIA, and metabolic alkalosis
What is the MOA of the thiazides
inhibits Na+/Cl co transporter
How do the thiazides decrease blood pressure
- Decreases fluid volume by preventing the reabsorption of Na+ in the DCT
- Stimulated PG production leading to vasodilation
What drugs can interfere with the ability of thiazides to treat hypertension
NSAIDs (interfere with the anti-hypertensive effect of PGs)
What drugs can be used with the thiazides to prevent hypokalemia
BB, ACEI, or ARBs (diminish K loss by blunting diuretic induced rise in renin and aldosterone levels)
or use with a K+ sparing diuretic
What class of drug will exacerbate the hyperlipidemic and hyperglycemic effects of the thiazides
Beta Blockers
Contraindication of the thiazides
existing hypokalemia
Relative contraindication of the thiazides
Pregnancy
What is the MOA of the loop diuretics
inhibits the Na+/K+/2Cl- co-transporter in TAL of hence
What is the prototype loop diuretic
furosemide
What are the differences in efficacy between the thiazide s and the loop diuretics
Furosemide has a short duration of action than thiazide, less effective in patients with normal renal function (due to rebound sodium retention)
What patient population are the loop diuretics usually reserved for
Patients refractory to thiazides, pts with moderate to severe renal insufficiency or CHF
What are the major side effects of the loop diuretics
Hyponatremia, HYPOKALEMIA, impaired diabetes control, increased LDL/HDL, REV. OTOTOXICITY
What drug can interfere with the ability of the loop diuretics to treat hypertension
NSAIDs (interfere with the anti-hypertensive effect of PGs)
What drug is to be avoided taken with the loop diuretics to avoid toxicities
Aminoglycosides (enhance ototoxicity and nephrotoxicity)
What are the 2 types (MOAs) of the K+ sparing diuretics
Aldosterone receptor antagonist (Spironolactone and eplerenone) and ENaC blocker (triamterene and amiloride)
In what context are the K+ sparing diuretics used to treat hypertension
NOT used alone for treatment, used in combo with other diuretics (usually to correct hypokalemia)
Generally adverse effect of the K+ sparing diuretics
HYPERKALEMIA
Adverse effect of spironolactone
gynecomastia
Contraindications of K+ sparing diuretics
any state that can lead to hyperkalemia, combination with drugs that inhibit the RAS (ACE-I, ARBs, BBs)
Selected drug interaction of the K+ sparing diuretics
NSAIDs (PG synthesis), ACE-I, ARBs, BBs
What is the common MOA of the Calcium channel blockers
- inhibit Ca2+ influx into vascular smooth muscle thru L-type Ca channels
- relax peripheral arterial vascular smooth muscle and decrease TPR (due inhibition of MLCK activity due to decrease in Ca-calmodulin)
What are the 2 main types of Ca Channel blockers
dihydropyridines and non-dihydropyridines
What differentiates dihydropridines and non-dihydropyridines
Non-dihydropyridines also reduce Ca current in CARDIAC pacemaker cells and reduce conduction in AV node –> lower HR and contractility (due to decrease Ca-induced Ca release from myocyte SR) –> reduce cardiac output
MOA of Nifedipine (prototype)
Dihydropyridine –> selective vasodilator of vascular smooth muscle
How is Nifedipine metabolized? How does that impact who is administered it?
P450 system - avoid in patients with liver disease and consider drug interactions that interfere with P450 system
Side effects of Nifedipine
acute tachycardia (reflex sympathoexcitation), peripheral edema (arteriolar dilation > ventilation)
MOA of Diltiazem
non-dihydropyridine –> inhibits sinus node as well as L-type Ca channels of myocytes and vascular smooth muscle –> reduces both cardiac output and peripheral resistance
Side effects of Diltiazem
bradycardia (slowed rate and conduction)
MOA of verapamil
non-dihydropyridine –> potent effect of the heart with more pronounced reduction of currents –> reduces both cardiac output and resistance
Side effects of verapamil
constipation and bradycardia
Relative contraindication for CCBs
pts with liver failure (drugs are metabolized by liver) and patients with SA or AV node conduction disturbances should NOT be given verapamil nor diltiazem (caution in pts on BBs for this reason)
MOA of the sympatholytic drugs to treat hypertension
reduce sympathetic drive to the heart and/or blood vessels –> decreased venous return, cardiac output, TPR, and renin release
MOA of the centrally acting agents for treating hypertension
reduce sympathetic output from the vasopressor centers in the brainstem
MOA of Clonidine (prototype)
alpha2 agonist at medullary cardiovascular regulatory centers –> decreases symp. outflow from CNS to vascular smooth muscle
Side effects of Clonidine
sedation, dry mouth, contact dermatitis (due to transdermal patch)
Why is Guanfacine a better choice over clonidine
has a longer half-life, less chance of rebound (hypertensive crisis)
What are the significant dangers when a patient misses a dose of Clonidine or abruptly stops taking it
rebound hypertension
MOA of methyldopa
crosses BBB and in converted to methyl-NE and acts as alpha2 agonist as well as competes with L-DOPA for DOPA decraboxylase preventing the production of dopamine and NE or EPI in peripheral nerves
What medication with methyldopa interfere with
L-DOPA for parkinsons
What are the side effects of methyldopa
Sedation
Contraindication for methyldopa
liver disease
In what specific condition is methyldopa used most extensively in
Hypertension during pregnancy