Antihypertensives2 Flashcards
What is the mechanism of a drug that ends in ‘pril’?
They are ACE inhibitors, which prevents conversion of AngI to AngII. Also prevents inactivation of bradykinins so increases their levels. Potent antiHTN drug.
What effect does AngII have on thirst?
it makes you thirsty
What effect does AngII have on blood vessel wall thickness?
it stimulates thickening and neo-imtima formation in blood vessels
What is captopril? What is its mechanism? What is unique about it?
ACE inhibitor that increases synthesis of prostaglandins. Also delays progression of renal disease in Type I diabetics.
What is enalapril? What is its mechanism? What is unique about it?
prodrug converted to potent ACE inhibitor (enalaprilat). Used IV for HTN emergencies
What is lisinopril? What is its mechanism? What is unique about it?
lysine derivative of enalaprilat, renoprotective ACE inhibitor
What is ramipril? What is its mechanism? What is unique about it?
prodrug ACE inhibitor. Long lasting, once daily.
What are adverse effects of ACE inhibitors
hypotension or Na depletion. Hyperkalemia, dry cough (related to bradykinin actions). Angioedema (potentially fatal and serious)
What is the mechanism of drugs that end in ‘sartan’?
they are AngII receptor antagonists (ARBs). Stop most actions of AngII, BUT do not effect bradykinin or other kinins so drug of choice when ACE inhibitors cause dry cough.
What is losartan? What is its mechanism? What is unique about it?
an ARB prodrug that is also a competitive antagonist of thromboxaneA2 receptor. Also increases Uric acid urinary excretion and inhibits CYP activity.
Which ARB has the shortest half-life? Which has the longest?
Losartan is shortest.
Telmisartan is longest acting.
What is telmisartan? What is its mechanism? What is unique about it?
ARB. It is unique because it is not cleared by kidney, thus good for patients with renal failure. Also has longest half-life of all ARBs.
Which ARB can be used to treat gout?
losartan, it has a unique side-effect of increases uric acid urinary excretion.
What is aliskiren? What is its mechanism? What is unique about it?
Renin inhibitor. antiHTN. Not commonly used alone because it is not as efficacious and expensive
What is verapamil? What is its mechanism? What is unique about it?
cardiac L-type Ca channel blocker of phenylalkylamine class. Selective for myocardium, less effective as systemic vasodilator. Dilate coronary artery, but can cause congestive heart failure. Migraines
What are dihydropyridines?
L-type Ca channel blockers. Selectively block L-type Ca channels in blood vessels. Used for HTN because they decrease SVR and MAP.
What is diltiazem? What is its mechanism? What is unique about it?
mixed Ca channel blocker of the benzothiazepine class. Intermediate between verapamil and dihydropyridines in selectivity for vascular and cardiac Ca channels
What is nifedipine? What is its mechanism? What is unique about it?
short acting L-type Ca channel dihydropyridine. Should NOT be used for HTN because it can increase HR by sympathetic reflex action
What are the benefits of dihydropyridines?
very effective in low renin HTN.
What are the adverse effects of dihydropyridines?
no proven survival benefit. can cause peripheral anklde edema and constipation.
What is hydralazine? What is its mechanism? What is unique about it?
selective smooth muscle vasodilator (arterioles only). Triggers reflex sympathetic stimulation and increases catecholamine/renin secretion. Reflex increase in HR and contractility and fluid retention. Can cause palpitations, tachycardia, lupus-like syndrome.
What is minoxidil? What is its mechanism? What is unique about it?
relaxes arteriolar smooth muscle by opening Kchannels in smooth muscles. Dilates arteries but not veins. Reflex tachycardia and powerful renin secretion activator. Causes hirsutism (also used to regrow hair)
What is diazoxide? What is its mechanism? What is unique about it?
IV HTN treatment. opens K channels to stabilize resting membrane potential. Requires higher input to depolarise and prevents smooth muscle contraction. Reflex tachycardia, and Na retetion. Renin secretion and Increased CO. Inhibits insulin release so hyperglycemia.
What is fenoldopam? What is its mechanism? What is unique about it?
D1 agonist. IV admin for HTN emergencies. Rapidly metabolized. T1/2 < 10 min. Reflex tachycardia and increased IO pressure. Avoid in gluacoma
What is nitroprusside? What is its mechanism? What is unique about it?
prodrug. Forms NO to stimulate smooth muscle cGMP to cause relaxation of arterioles AND veins. Useful for treatment of heart failure. Reduces CO in normal people, BUT increases it in patients with LVF because TPR is reduced. Very short halflife and IV. Can cause excessive hypotension, pronounced tachycardia and palpitaitons. Metabolized to cyanide so no long term use
What effect would an A2 agonist have?
it activates A2 receptors in brain, which INHIBITS sympathetic activity
What is clonidine? What is its mechanism? What is unique about it?
central A2 agonist. Decreases sympathetic impulses and decreases TPR and HR. Can treat ADHD or for pain. can cause sedation and must be withdrawn slowly at risk of hypertension.
What is alpha-methyl-DOPA? What is its mechanism? What is unique about it?
converted into a-methyl NE, a false trasmitter. Is a A2 agonist. Used to treat preeclampsia. Sedation. Can cause autoimmune reactions (+coombs)
What is bosentan? What is its mechanism? What is unique about it?
endothelin-1 and endothelin-2 receptor antagonist. Endothelin is a powerful vasoconstrictor. Used to treat pulmonary artery HTN. Severe liver toxicity.
What is a special advantage of alpha blockers?
they can improve both lipid profile and insulin resistance. Particularly useful in young patients who wish to remain active
What type of HTN drug can be used to prevent stage fright?
B blockers.
What is bisoprolol? What is its mechanism? What is unique about it?
B1-blocker used with ACEIs and diuretics. Is gold standard of treatment.
Which IV drug is used during hypertensive emergencies, is short acting, and acts on G-coupled protein receptor?
fenoldopam. Acts on D1 receptor and quickly reduced BP.
Which IV drug is used during hypertensive emergencies, is short acting, and acts by releasing nitric oxide?
nitroprusside
