HTN 2 Drugs 3 Flashcards
α-2 agonists, α-1 blockers, βblockers will effect the
Sympathetic nervous system
Pathophysiology:
Peripheral vascular resistance is due to Increased sympathetic
activity leads to
Stimulation of adrenal glands to release epinephrine (adrenaline)and norepinephrine (noradrenaline)
Causes constriction/contraction of smooth muscle arterioles get smaller increase resistance/pressure
Decreased perfusion to organ systems (i.e. kidney)
Agonist Alpha1 vs. Alpha2
Alpha1
Vasoconstriction (and reflex bradycardia)
Bladder sphincter contraction (means go to bathroom)
Reduced lipolysis
Alpha2
Decrease pre-synaptic NE release (reduced sympathetic outflow)
Alpha1-blockers MOA
: Selectively block α1-receptors on smooth muscle cells of peripheral vasculature
BP = CO X PVR
• Lower BP via vasodilation, ↓ PVR
• ↓ standing BP > supine BP (orthostasis) –> When we stand up the B.p go down and we feel dizzy
_____ blockers predominantly lower blood pressure that causes orthostatic hypotension supine BP (orthostasis)
Alpha 1
Alpha1 -blockers are
Doxazosin (Cardura) 1 – 8 Daily
Apha 1 blocker (doxazosin)leads to
less contraction of bladder leads to person have to go less to bathroom
Prazosin is only used for
nightmares
Clinical Considerations: of Alpha 1 blocker
Alpha 1 blocker is the last line therapy because they do not have long term effects,
Alpha-blocker help pt with
BPH (benefits: improves urine flow and decrease frequency) and decrease HR at the same time
ADEs: of Alpha 1 blocker
Orthostatic hypotension • First dose syncope (occurs 1-3 hrs after first dose) • Dizziness • Reflex tachycardia • Peripheral edema • Sexual dysfunction
Alpha2 Agonists MOA:
Stimulate α2 pre-synaptic receptors in the brain
• ↑ inhibitory neuron activity
• ↓ sympathetic outflow
P = CO x decrease PVR
Alpha2 Agonists lower B.P VIA
lowering the PVR
Clonidine: can lower HR, CO
Methyldopa: less effect on HR, CO
Alpha2 Agonists: are
Clonidine (Catapress) 0.1 – 0.8 BID Clonidine patch (Catapres – TTS) 0.1 – 0.3 Weekly
Clonidine path will reduce
potential side effects due to long acting
If pt taking multiple B.p medications and it is not helping
add clonidine as the last line
iF WE ABRUPTLY stop clonidine oral
there will be rebound HTN so tell pt not to stop taking right away
Possible indications: of alpha 2 agonist
Resistant HTN (clonidine) Pregnancy (methyldopa)
The adverse effect of Alpha 2 agonist (clonidine) are
Significant CNS adverse effects: impaired concentration, nightmares, vertigo
(methyldopa), sedation, drowsiness, fatigue
• Orthostatic hypotension
• Dry mouth
• Depression (clonidine)
• Abrupt discontinuation of clonidine → rebound HTN (less so in TTS vs. PO)
β1 vs. β2 When we stimulate
β1 –> Heart
•Increase heart rate
•Increase renin secretion
β2 --> Lungs & Periphery •Smooth muscle relaxation (bronchioles) •Peripheral vasodilation •Skeletal muscle stimulation (tremors) •Glycogenolysis & gluconeogenesis
Beta-Blockers (BB): MOA
: Competitively inhibit catecholamine neurotransmitters at
• β1 (cardiac) receptors
• β2 (smooth muscle/lungs) receptors
Different types of Beta-blockers
– Non-selective (β1 and β2 activity)
– Cardioselective (β1 activity only)
– Some w/ β2 agonist properties
– Others are mixed α1/ β
Non-selective Beta1/Beta2 Blockers MOA
antagonists of β1/ β2receptors
Non-selective Beta1/Beta2 are
PropranololPropranolol (Inderal) 160 - 480 BID
Propranolol long-acting (Inderal LA) 80 – 320 Daily
Clinical Considerations: of Non-selective Beta1/Beta2 (PROPRANOLOL)
Avoid in pts with reactive airways disease, caution for blocking hypoglycemia sx
(except sweating)
Avoid in pt with hypoglycemia
Avoid in pt with Asthma blocking that smooth muscle will be harmful and can cause asthma
someone with uncontrolled hyperthyroidism ______ will help them.
Beta-blockers
Additional indications / clinical use of Propranolol
Angina, post-MI CV event prevention, atrial fibrillation, atrial flutter, supraventricular arrhythmias, migraine prophylaxis, tremors
These agents improve these disease states.
Beta1 Selective Blockers are
Atenolol (Tenormin) 25 – 100 Daily Metoprolol succinate (Toprol XL) 50 – 400 Daily - BID Metoprolol tartrate (Lopressor) 50 – 200 BID
Beta1 Selective BlockersMOA
β1
-selective antagonists (cardioselective)
• Limited effect on pulmonary function & peripheral vessels
• Preferred in pts with bronchospastic airway disease requiring a BB
• Selectivity lost at higher doses
Additional clinical indications/use in clinical practice of B1 selective
Angina Post MI CV event prevention Migraine prophylaxis Heart failure Atrial fibrillation Atrial flutter
Mixed Alpha1/Beta Blockers MOA
Mixed α1/β-blockers
• Less effect on HR and CO than pure β-blockers
• Additional effect on TPR (α1 blocker)
Mixed Alpha1/Beta Blockers are
Carvedilol (Coreg CR) 20 – 80 Daily
Labetalol (Normodyne) 200 – 800 BID
Clinical Considerations of A1/B blockers
Carvedilol: Mortality benefit in heart failure, after stabilized
Labetalol: Increased safety data in pregnancy, hypertensive emergency (IV)
Beta Blockers & ACC/AHA Guidelines are
BB NOT recommended as first-line for uncomplicated HTN
Beta-blockers are reserved for
Reserve for patients with hypertension plus compelling co-existing
a condition that would benefit from a beta-blocker:
• Heart Failure –> Prevent heart attack and reduce risk and decrease hospitalization
• Post-MI
• Angina
Beta-Blockers clinical considerations
Abrupt discontinuation can cause rebound HTN (taper over 1-2 weeks)
Caution in asthma/COPD, especially with nonselective agents
pt with Asthma and COPD should avoid
Beta blockers
ADE of Beta-blocker is
Bronchospasm; worsening of pre-existing asthma
• Bradycardia
• Fatigue, exercise intolerance, ↓ AV nodal conduction
• Insomnia, sleep disturbances, sexual dysfunction
• Masked signs and symptoms of hypoglycemia (except sweating)
• Cold hands, feet
Contraindications: of Beta blocker
avoid in pt with Sinoatrial or atrioventricular (AV) node dysfunction
Decompensated HF
Severe bronchospastic disease
Avoid Beta-blockers with
Non-DHP CCBs –> Verapamil and diltiazem because they reduce blood pressure significantly.
The agents that block B1 selectively, At higher doses
their selectivity loss and will have blockade on B2 receptor and they will have shortness of breath.
Monitoring with BB is
BP
• HR
• BG if have diabetes
• Signs and symptoms of asthma/COPD
B1 prevent
Prevent tremor and migraine
