Module 3.1: ANTI-HYPERTENSIVE (ANTI-HPN) Flashcards
Normal bp
Prehypertension
120–135/80–89
Hypertension
≥ 140/90
Stage 1
140–159/90–99
Stage 2
≥ 160/100
- No specific cause can be determined
- investigation of autonomic nervous system function, baroreceptor reflexes, the RAAS, and the kidney has failed to identify a single abnormality as the cause of increased peripheral vascular resistance
ESSENTIAL/ PRIMARY HTN
- Specific cause identified
- Possible causes: renal artery constriction, coarctation of the aorta, pheochromocytoma, Cushing’s disease, and primary aldosteronism.
SECONDARY HTN
BP is maintained by three anatomic sites:
o Arterioles
o postcapillary venules (capacitance vessels)
o heart
…contributes to maintenance of blood pressure by regulating the volume of intravascular fluid (triggering the juxtaglomerular aparatus)
kidneys
…mediated by autonomic nerves, act in combination with humoral mechanisms, including RAAS, to coordinate those anatomical sites’ functions and to maintain normal blood pressure
Baroreflexes
- responsible for rapid, moment-to-moment adjustments in blood pressure: transition from a reclining to an upright posture
- Central sympathetic neurons arising from the vasomotor area of the medulla are tonically active
Postural Baroreflex
stretch of the vessel walls brought about by the internal pressure (arterial blood pressure).
Carotid baroreceptors:
…causes (1) direct constriction of resistance vessels and (2) stimulation of aldosterone synthesis in the adrenal cortex ->increases renal sodium absorption and intra- vascular blood volume
Angiotensin II
…regulate water reabsorption by the kidney
Vasopressin (posterior pituitary gland)
Prehypertension
120–135/80–89
Hypertension
≥ 140/90
Stage 1
140–159/90–99
Stage 2
≥ 160/100
- No specific cause can be determined
- investigation of autonomic nervous system function, baroreceptor reflexes, the RAAS, and the kidney has failed to identify a single abnormality as the cause of increased peripheral vascular resistance
ESSENTIAL/ PRIMARY HTN
- Specific cause identified
- Possible causes: renal artery constriction, coarctation of the aorta, pheochromocytoma, Cushing’s disease, and primary aldosteronism.
SECONDARY HTN
BP is maintained by three anatomic sites:
o Arterioles
o postcapillary venules (capacitance vessels)
o heart
…contributes to maintenance of blood pressure by regulating the volume of intravascular fluid (triggering the juxtaglomerular aparatus)
kidneys
…mediated by autonomic nerves, act in combination with humoral mechanisms, including RAAS, to coordinate those anatomical sites’ functions and to maintain normal blood pressure
Baroreflexes
- responsible for rapid, moment-to-moment adjustments in blood pressure: transition from a reclining to an upright posture
- Central sympathetic neurons arising from the vasomotor area of the medulla are tonically active
Postural Baroreflex
MECHANISM OF ACTION:
Reduction of HR and CO
CNS effect
Inhibition of renin release
Reduction in venous return and plasma volume
Reduction in peripheral vascular resistance
Reduction in vasomotor tone
Improvement in vascular compliance
Resetting of baroreceptor levels
Effects on prejunctional B receptors, reduction in NE release
Attenuation of pressor response to catecholamines with exercise and stress (newer generation decrease in ADRS due to B1 selectivity; B1 is the adrenergic receptor in the heart)
BETA BLOCKERS {-OLOL}
…causes (1) direct constriction of resistance vessels and (2) stimulation of aldosterone synthesis in the adrenal cortex ->increases renal sodium absorption and intra- vascular blood volume
Angiotensin II
…regulate water reabsorption by the kidney
Vasopressin (posterior pituitary gland)
Normal bp
Goal of Anti-HTN:
1. REGULATE CO
Tachycardia -> Dec filling time -> Dec stroke volume -> Dec cardiac output
Goal of Anti-HTN:
2. PERIPHERAL RESISTANCE
muscle relaxation -> arteries dilatation, fall in Peripheral Resistance [PR], then BP goes down
right part of the heart; blood returning to the heart; aka degree of distention particularly your right atrium
Preload
anything that decrease venous return
preload unloaders
decrease vasoconstriction in arterioles and arteries
Afterload unloaders
lower blood pressure by depleting the body of sodium and reducing blood volume
Diuretics
ower blood pressure by reducing peripheral vascular resistance, inhibiting cardiac function, and increasing venous pooling in capacitance vessels.
Sympathoplegic agents
reduce pressure by relaxing vascular smooth muscle, thus dilating resistance vessels and—to varying degrees—increasing capacitance as well
Direct vasodilators
Appropriate for the treatment of arterial HTN, esp in patients who have concomitant ischemic heart disease, HF or arrhythmias
BETA BLOCKERS {-OLOL}
They are highly heterogenous with respect to various properties
They reduce mortality, nonfatal re-infarction rates and improve clinical outcomes in patients with stable ventricular dysfunction who are receiving conventional HF treatment
BETA BLOCKERS {-OLOL}
MECHANISM OF ACTION:
Reduction of HR and CO
CNS effect
Inhibition of renin release
Reduction in venous return and plasma volume
Reduction in peripheral vascular resistance
Reduction in vasomotor tone
Improvement in vascular compliance
Resetting of baroreceptor levels
Effects on prejunctional B receptors, reduction in NE release
Attenuation of pressor response to catecholamines with exercise and stress (newer generation decrease in ADRS due to B1 selectivity; B1 is the adrenergic receptor in the heart)
BETA BLOCKERS {-OLOL}
INDICATION:
- Treatment for arterial hypertension; especially in concomitant ischemic heart failure and arrhythmia
would not only control pressure, also decrease ischemia by decreasing O2 demand;
arrhythmia: block electric conduction>reduction in heart rate
BETA BLOCKERS {-OLOL}
improve survival after MI
METOPROLOL, CARVEDILOL
MOA: reduce arterial pressure by dilating both resistance and capacitance vessels
DOC for Pt with HTN due to BPH
ALPHA BLOCKERS
…lower BP by blocking postsynaptic vasoconstrictor effects of Norepinephrine
Selective Alpha1 adrenergic antagonists
…cause balanced arterial and venous dilation, with no increase in CO
Hemodynamically, selec a1 receptor inihibitors
[ALPHA BLOCKERS] ADVERSE DRUG REACTION:
Tend to cause greater BP lowering in the upright compared to supine position
ORTHOSTATIC HYPOTENSION]
Non-selective alpha blockers given for patients diagnosed with pheochromocytoma
PRAZOCIN, TAMSULOSIN]
…reduce BP by decreasing SNS outflow, systemic vascular resistance and HR
Central alpha 2 sympathetic agonists
…is an agonist for both central a2 and II-imidazoline receptors
CLONIDINE
…deplete nerve terminal with NE, decrease reflex peripheral arterial and venous constriction, and predispose to orthostatic hypotension
Peripheral sympatholytics
ADR: orthostatic hypotension; rebound hypertension especially when you suddenly stopped using the drug
IND: acute hypertension
CLONIDINE
ADR: x’ss tachycardia causing increase in myocardial o2 demand
Nifedipine
IND: pregnancy induced hypertension
Alpha methyldopa [aldomet]
[ACE-Inhibitors]
ADVERSE DRUG RESPONSE
- in pt with hypovolemia leads to severe hypotension;
- acute renal failure (particularly in patients with bilateral renal artery stenosis or stenosis of the renal artery of a solitary kidney),
- dry cough sometimes accompanied by wheezing, and
- angioedema
ADR: orthostatic hyptension, sedation, increase prolactin production (M and F)
METHYLDOPA
Effective work primarily by selective blockade of AT-I receptors; leading to the same effect as ACE-I
Effective as monotherapy but when combined with other antihypertensive agents, are effective in virtually all populations
ANGIOTENSIN (AT) RECEPTOR BLOCKERS [ARB] {-SARTAN}
Contraindication: depressive pt; TCA may block antiHTN effect of…
CLONIDINE
inhibits the release of norepinephrine from sympathetic nerve endings
ADRENERGIC NEURON-BLOCKING AGENT
ADR: HYPOTENSION, delayed or retrograde ejaculation (returns back into the bladder), diarrhea, HTN crisis among pt with pherochromocytoma
ADRENERGIC NEURON-BLOCKING AGENT
CI:TCA, may lead to severe HTN crisis
ADRENERGIC NEURON-BLOCKING AGENT
for treatment of patients with HF and Chronic kidney diseases
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM [RAAS] BLOCKERS
- increases BK [bradykinin] concentration – leading to cough [remember patho: bradykinin is one of the chemicals release by neutrophils during asthmatic attacks; this causes irritation to the bronchial airways causing cough as ADR]
- Long term use may lead to angiotensin escape
ACE INHIBITORS [ACE-I] {- PRIL}
With the exception of_____ & _____, ACE-I are prodrugs, which improves their absorption before hydrolysis to active diacids in the liver or intestines
[EX. ENALAPRIL ENALAPRILAT the active metabolite]
LISINOPRIL and CAPTOPRIL
ACE-I drug whose action could be cancelled by ICATIBANT
CAPTOPRIL
ACE-I drug which is also a lysine derivative of enalaprilat
LISINOPRIL
ACE-Inhibitors are distinguished by…
sulfhydryl (captopril), phosphinyl (fosinopril), or carboxyl side groups
chronic kidney disease patients taking ACE-Inhibitors would lead to…
HYPERkalemia
[ACE-Inhibitors]
ADVERSE DRUG EFFECT
- in pt with hypovolemia leads to severe hypotension;
- acute renal failure (particularly in patients with bilateral renal artery stenosis or stenosis of the renal artery of a solitary kidney),
- dry cough sometimes accompanied by wheezing, and
- angioedema
[ACE-Inhibitors]
CONTRAINDICATION
pregnancy
Effective work primarily by selective blockade of AT-I receptors; leading to the same effect as ACE-I
Effective as monotherapy but when combined with other antihypertensive agents, are effective in virtually all populations
ANGIOTENSIN (AT) RECEPTOR BLOCKERS [ARB] {-SARTAN}
…act by binding selectively to the AT-I receptor
ANGIOTENSIN (AT) RECEPTOR BLOCKERS [ARB]
- competitive (IRBESARTAN, VALSARTAN) or - insurmountable (CANDESARTAN or LOSARTAN)
[ARB]
ADVERSE DRUG RESPONSE
ERECTILE DYSFUNCTION
Renin converts angiotensinogen to angiotensin I. Block by _____ blocks the sequence at its start.
aliskiren
ACE is responsible for activating angiotensin I to angiotensin II and for inactivating bradykinin, a vasodilator normally present in very low concentrations. ______ block this enzyme thus decreases the concentration of a vasoconstrictor and increases the concentration of a vasodilator.
ACE-I
The ___________ lack the effect on bradykinin levels, which may explain the lower incidence of cough observed with these agents.
AT1 receptor antagonists
MOA:
Block Na/K/2Cl transporter in renal loop of Henle
EFFECT:
Reduce blood volume and poorly understood vascular effects + greater efficacy
INDICATION:
Severe hypertension, heart
failure
Loop diuretics:
Furosemide
These CCBs are more CARDIOSELECTIVE
VERAPAMIL AND DILTIAZEM
These CCBs are more VASOSELECTIVE
DIHYDROPYRIDINE
- opening of potassium channels in smooth muscle membranes by minoxidil sulfate, the active metabolite
- arteriolar dilation
- PO drug/orally active
- ADR: Headache, sweating, hypertrichosis
MINOXIDIL
- arterial dilation; given with nitrates for HF and HTN patients
- in Pt with IHD, may lead to reflex tachycardia and sympathetic stimulation may provoke angina or ischemic arrhythmias
- PO drug/orally active
- ADR: nausea, anorexia, palpitations, sweating, and flushing
HYDRALAZINE
- treating hypertensive emergencies as well as severe heart failure
- BOTH arteries and vein dilatation
- activation of guanylyl cyclase, either via release of nitric oxide or by direct stimulation of the enzyme resulting to an increase in cGMP leading to smooth muscle relaxation
NITROPRUSSIDE
- rapid fall in systemic vascular resistance and mean arterial blood pressure
- MOA: opening potassium channels and stabilizing the membrane potential at the resting level
- arteriolar dilatation
DIAZOXIDE
ADR: excessive hypotension, resulting from the recommendation to use a fixed dose of 300 mg in all patients
DIAZOXIDE
ADR: accumulation of cyanide; metabolic acidosis, arrhythmias, excessive hypotension, and death
NITROPRUSSIDE
- peripheral arteriolar dilator used for hypertensive
- emergencies and postoperative hypertension
FENOLDOPAM
- ADR: reflex tachycardia, headache, and flushing
- CI: glaucoma Pt – increases IOP more
FENOLDOPAM
Direct Renin Inhibitors
ALISKIREN
Dopamine agonists
FENOLDOPAM
MOA:
Block Na/Cl transporter in
renal distal convoluted tubule
EFFECT:
Reduce blood volume and poorly understood vascular effects
INDICATION:
Hypertension, mild heart
failure
Thiazides:
Hydrochlorothiazide
MOA:
Block Na/K/2Cl transporter in renal loop of Henle
EFFECT:
Reduce blood volume and poorly understood vascular effects + greater efficacy
INDICATION:
Severe hypertension, heart
failure
Loop diuretics:
Furosemide
MOA: Releases nitric oxide
EFFECT: Powerful vasodilation
INDICATION: Hypertensive emergencies
ROA: Parenteral • short duration
TOXICITY: Excessive
hypotension, shock
Nitroprusside
SYMPATHOPLEGICS, CENTRALLY ACTING Toxicity:
hemolytic anemia
methyldopa
also used in withdrawal
from abused drugs
Clonidine
MOA:
Blocks vesicular amine
transporter in noradrenergic
nerves and depletes transmitter stores
EFFECTS:
Reduce all sympathetic effects, especially cardiovascular, and reduce blood pressure
INIDICATION: Hypertension but rarely used
TOXICITY: psychiatric depression, gastrointestinal
disturbances
Reserpine
MOA:
Interferes with amine release
and replaces norepinephrine
in vesicles
EFFECTS:
Reduce all sympathetic effects, especially cardiovascular, and
reduce blood pressure
INIDICATION: Hypertension but rarely used
TOXICITY: Severe orthostatic hypotension; sexual dysfunction
Guanethidine
MOA:
Selectively block α1
adrenoceptors
EFFECTS:
Prevent sympathetic
vasoconstriction • reduce
prostatic smooth muscle tone
INDICATION:
Hypertension • benign prostatic hyperplasia
TOXICITY:
Orthostatic hypotension
ALPHA BLOCKERS
• Prazosin
• Terazosin
• Doxazosin
Nonselective prototype BETA blocker
Propranolol
Very widely used b1-selective blocker
Atenolol
MOA: Block β1 receptors
EFFECTS: Prevent sympathetic cardiac
stimulation • reduce renin secretion
INDICATION:
Hypertension • heart
failure
BETA BLOCKERS
• Metoprolol, others
• Carvedilol
also blocks α receptors
carvedilol
MOA: Nonselective block of L-type calcium channels
EFFECTS:
Reduce cardiac rate and output • reduce vascular resistance
INDICATION:
Hypertension, angina,
arrhythmias
- Verapamil
* Diltiazem
MOA:
Block vascular calcium
channels > cardiac calcium
channels
EFFECTS:
Reduce vascular resistance
INDICATION:
Hypertension, angina
Nifedipine,
amlodipine, other
dihydropyridines
MOA: Causes nitric oxide release
EFFECTS:
Vasodilation • reduce vascular resistance • arterioles more sensitive than veins • reflex tachycardia
INDICATION: Hypertension
TOXICITY: Angina,
tachycardia • Lupus-like syndrome
Hydralazine
MOA:
Metabolite opens K channels
in vascular smooth muscle
INDICATION: Hypertension •
also used to treat hair loss
TOXICITY: Angina,
tachycardia • Hypertrichosis
Minoxidil
MOA: Releases nitric oxide
EFFECT: Powerful vasodilation
INDICAtion
Nitroprusside
MOA: Activates D1 receptors
EFFECT: Powerful vasodilation
INDICATION: Hypertensive emergencies
ROA: Parenteral • short duration
TOXICITY: Excessive
hypotension, shock
Fenoldopam
MOA: Opens K channels
EFFECT: Powerful vasodilation
INDICATION: Hypertensive emergencies
ROA: Parenteral • short duration
TOXICITY: Excessive
hypotension, shock
Diazoxide
MOA: α, β blocker
EFFECT: Powerful vasodilation
INDICATION: Hypertensive emergencies
ROA: Parenteral • short duration
TOXICITY: Excessive
hypotension, shock
Labetalol
MOA: Inhibit angiotensin converting enzyme
EFFECTS:
Reduce angiotensin II levels •
reduce vasoconstriction and
aldosterone secretion • increase bradykinin
INDICATION:
Hypertension • heart failure, diabetes
ROA: Oral
TOXICITY: Cough, angioedema • hyperkalemia
• renal impairment
• teratogenic
(ACE-I) Captopril
MOA: Block AT1 angiotensin
receptors
EFFECTS:
Reduce angiotensin II levels •
reduce vasoconstriction and
aldosterone secretion
INDICATION:
Hypertension • heart failure
ROA: Oral
TOXICITY: less Cough, angioedema • hyperkalemia
• renal impairment
• teratogenic
(ARBs) Losartan
MOA: Inhibits enzyme activity of renin
EFFECT: Reduces angiotensin I and II and
aldosterone
INDICATION: Hypertension
ROA: Oral
TOXICITY: Hyperkalemia,
renal impairment • potential
teratogen
RENIN INHIBITOR
• Aliskiren