Antihypertensives Flashcards
What are the 4 anatomic sites of BP control?
- resistance in arterioles
- capacitance in venules
- pump output of the heart (CO)
- kidneys (most common site of action to treat HTN)
What are two compensatory response to ↓ BP?
- tachycardia (due to the ↑ sympathetic outflow that results form the dec. BP)
- salt and water retention
What are first line agents for treatment of HTN?
- ACE inhibitors, alpha receptor blockers, calcium channel blocker and thiazide diuretics
Second line agents for HTN:
- β blockers, aldosterone antagonists
α blockers are _______ line treatment for HTN
1st line
What drugs are ACE inhibitors? And what patients are they usually given to?
- captopril
- enalapril
- lisinopril
- PRIL
1st line for HTN, especially for diabetics and patients with chronic kidney disease
Patient with HTN and also has diabetes and/or chronic renal disease. What drug would you give to treat their HTN?
Ace inhibitor: captopril, enalapril, lisinopril
ACE converts _______ to _______ and also breaks down _________
Angiotensin I → angiotensin II
Bradykinin
______________ drugs to treat HTN do NOT induce reflex tachycardia
ACE inhibitor
what is the effect of bradykinin levels in someone taking ACE inhibitors?
↑ bradykinin because ACE breaks it down;
The ↑ bradykinin produces a cough in patients
Angiotensin II acts on the __________ receptors which leads to: (3)
AT1 receptors;
- vascular growth
- vasoconstriction
- Na retention
When giving an ACE inhibitor, can expect ↑ levels of ________ and ______
Renin and angiotensin I ; but doesnt do anything because ACE is inhibited
What is the effect of ACE inhibitors on sodium and postssium?
↓ in sodium retention
↑ in potassium rention (HYPERKALEMIA)
__________ preserve renal function in patients with either diabetic or non diabetic nephropathy when treating HTN
ACE inhibitors; angiotensin constricts the efferent arterioles so ACE inhibitors will vasodilate it and thus improving blood flow
Drugs that effect the renin pathway to treat HTN has show to be more effective in white/black patients
White
Someone taking a ACE inhibitor will have a slight ________ in GFR
↓ (vasodilation of efferent arteriole)
Clinical uses of ACE inhibitors:
- HTN
- preserve renal function in patients with diabetic or non diabetic nephropathy
- treatment in chronic heart failure
- standard fo care in patients following MI
What is a potential life threatening adverse effect of ACE inhibiti9ors?
Angioedema
ACE inhibitors should be given to patients with unilateral/bilateral/both renal artery stenosis.
UNILATERAL
Giving ACE inhibitors to someone with BILATERAL renal artery stenosis is CONTRAINDICATED
Contraindications of ACE inhibitors
- pregnancy
- patients wit BILATERAL renal artery stenosis → the efferent arteriole constriction is what maintains the GFR but giving ACE inhibitor will take this away and there is no other functional kidney to compensate
- patients with history of angioedema related to previous treatment with an ACE inhibitor and in patients with hereditary or idiopathic angioedema
Losartan and Vallartan and what type of drugs?
Angiotensin receptor blockers
MOA of angiotensin receptor blocker drugs:
- drugs: losartan and valsartan
- blocks angiotensin 2 type 1 receptors
- ↓ BP by: arteriolar and venous dilation
- blocks aldosterone secretion
- ↓ diabetic nephrotoxicity
NO INCREASE IN BRADYKININ LEVELS
With ARB’s we will see an ↑ in _______ which we dont see with ACE inhibitors
Angiotensin II; both will have ↑ renin and angiotensin I
What is the risk of angioedema in angiotensin receptor blockers?
Significantly lower compared to the risk seen with ACE inhibitors
_______ is a angiotensin receptor blocker that can be used to treat gout because ________
Losartan; it blocks URAT1 which then reduces plasma uric acid levels
What drug is a renin inhibitor and what conversion does it inhibit?
Aliskiren;
Angiotensinogen → angiotensin I
Patient has HTN and also has diabetes with albnumuria. What drug would you give to treat their HTN?
Captopril or other ACE inhibitors
Which drugs are calcium channel blockers?
- verapamil, diltiazem, nifedipine, amlodipine
Verapamil and other similar drugs in its class are 1st line agents for ______
HTN particularly in black or elderly patients
The least selective calcium channel blocker is _________ and thus has significant effects on:
Verapamil;
Cardiac AND vascular smooth muscle
What is verapamil used to treat?
Angina, supraventricular tachyarrhythmias, HTN, migraine and cerebral vasospasm
________ is also another non selective calcium channel blocker but has more/less effect on the heart than verapamil
Diltiazem; LESS
Both have same uses
Dihydropyridines (_________ and _________) which is a sub class of calcium channel blockers, have a greater affinity for _____________ calcium channels
Amlodipine and nifedipine;
Greater affinity for VASCULAR calcium channels than cardiac
The primary use of amlodipine is ________
HTN because it has affinity for vascular calcium channels
_____________ reduce calcium entry into smooth muscles to cause coronary and peripheral _________ and ____ BP
Dihydropyridines: amlodipine and nifedipine;
Vasodilation; ↓
You will not see reflex tachycardia in calcium channel blockers EXCEPT: ___________
Dihydropyridines: amlodipine and nifedipine
Can dihydropyridines be used to treat arrythmias?
NO because amlodipine/nifedipine only work on the vascular calcium channels and not the cardiac ones so they have no effect on the action potentials
High doses of short actin dihydropyridines calcium channel blockers can ↑ risk of ______
MI: excessive vasodilation and reflex cardiac stimulation)
Constipation is an adverse effect of what calcium channel blocker?
Verapamil
What are the AE’s of verapamil?
- constipation
- NEGATIVE inotropic effects
- gingival hyperplasia
non - dihydropyridine calcium channel blockers are contraindicated in:
- patients taking β blockers
- patients with 2nd or 3rd degree AV block
- patients with severe left ventricular systolic dysfunction
Thiazides are first line agents for ___________
Black or elderly patients with HTN
_____ diuretics are given in conjunction with loop or thiazides
K sparing
A patient has HTN with severe left ventricular dysnfunction, what is the first line treatment you prescribe them?
Aldosterone antagonist: spironolactone
