drugs quiz 3 Flashcards
(45 cards)
antihypertension drug selection
1) underlying med conditions 2) race 3) severity and resistance to tx 4) use of 2 agents is not uncommon
diuretics MOA
deplete sodium, reduce blood volume, ong term will decrease tpr
sympathoplegics MOA
reduce peripheral vascular resistance, also inhibit cardio function, increase pooling in venous capacitance vessels, thus reducing cardiac output
direct vasodilators MOA
relax vascular smooth muscle
anti-angiotensin agents MOA
inhibit production of aldosterone (retains Na and pumps out K) thus reducing peripheral vasccular resistance
mannitol
osmotic agent, acts in PCT. is not resorbed so water is retained
carbonic anhydrase inhibitors
Acetazolamide: lowers NaCO3 resorption, makes urine alkaline, used to treat epilepsy (not hypertension) but water is lost
loop diuretics
Furosemide and Bumetanide: inhibit luminal Na/K/2Cl pump. in thick ascending loop. reduces Nacl resoprtiona and water remains. very effective. hypokalemia (salt sensors activate aldosterone to resorb Na and excrete K i in distal tubule/collecting duct). inhibited by NSAIDs (use a cox 2 mechanism)
thiazides-diuretics
hydrochlorothiazide and chlorthalindone: inhibit NaCl (symporter) resorption in DC. hypokalemia (heart arrhythmia) blocked by NSAIDs
hypokalemia
lower insulin secretion and hyperglycemia
heart arrhythmias
potassium sparing diuretics
1) spironolactone: antagonizing effects of aldosterone (na/k antiporter turned off) in collecting tubules via blocage of mineralcorticoid recceptors
2) amiloride: na+ influx through ion channels in the luminal membrane- turns off same pump as spironolacctone
- weak and often used with other drugs. do not give if on ace inhibitor (makes hyperkalemia worse)
clonidine
alpha 2 agonist: central a2 receptors in medulla. reduces sympathetic tone which relaxes and decreased blood pressure. dry mouth and sedation common. (centrally mediated and dose dependent)
ganglionic blocking agents
mecamylamine: competitively block nicotinic cholinoreceptors on postganglionic neurons in both symp and parasymp.
sympathoplegia: excessive orthostatic hypo
parasympoplegia: constipation, urinary retention, glaucoma, blurred vision, dry mouth
rarely used- doesnt effect skeletal muscle
adrenergic blocking agents
guanethidine: inhibits release of NE by entering nerve and replaceing NE in vesicles. Orthostatic hypo and diarrhea (due to lack of symp). lowers sympathetic tone and get lower BP
beta blockers
cardioselective: atemolol and metoprolol: B1: slows down heart- also tx for angina
noncardioselective: propranolol and nadolol: B! and B2: slows down heart and inhibits renin.
beta and apha 1: labetolol and carvedilol
lower cardiac force, increased TPR (block vasodilate in skeltal muscles b2), decrease renin, bronchial constirction (dont give asthmatic), dec glycogenolysis, may mask tachy that accompanies hypoglycemia
alpha blockers
do not impair excercise tolerance. useful for astham and diabetes pts
cardioselective A1: parazosin and terazosin: A1 receptor specificity allows NE to exert unopposed negative feedback
noncardioselecctive: a1 and a2. phentolamine and phenoxybenzamine: blocks both so now any symp goes to betas (heart beats faster)
alpha 1 vasodilates
release NO from endothelium.
direcct vasodilator. hyrdrazoline
reduce calcium influx, smooth muscle relaxes
direct vasodilators: verapimil, diltiazam, nifedipine- treats angina and hypertension
hyperpolarize smooth msucle through K channel opening
direct vasodilator. minoxidil (rogaine)
activate dopamine receptors
direct vasodilator. fenoldapam
direct vasodilator comments
sodium nitroprusside also dialates. heart starts beating faster from barorecptors and sympathetic NS
ACE inhibitor
captopril: ace take angiotensin 1 to 2. (no aldosterone) and inactivates bradykinins a potent vasodilator
hyperkalemia
angitotensin 2 inhibitor
losartan: decrease peripheral resistance. no aldosterone so hyperkalemia
does not effect bradykinins
nitrates
treat angina pectoris- need 8 hours between doses- metabolized to NO
1) nitroglycerin: sublingual. unstable. glass bottle. expired means expired. 30 minutes or 8 hour patch
2) amyl nitrate: ccrush carpule and sniff- not used anymore
- orthostatic, tachycardia, compounds migraines
