Beta blockers, Alpha blockers and stimulants, direct, emergencies Flashcards
What are the Sympathetic effects of Alpha 1?
- Vasoconstriction
- Increased peripheral resistance
- Increased BP
- Mydriasis (dilate pupils)
- Increased closure of internal sphincter of the bladder
What are the Sympathetic effects of Alpha 2?
- Inhibition of norepinephrine release
- Inhibition of acetylcholine release
- Inhibition of insulin release
What are the Sympathetic effects of Beta 1?
- Tachycardia
- Increased lipolysis
- Increased myocardial contractility
- Increased release of renin
What are the Sympathetic effects of Beta 2?
- Vasodilation
- Slightly decreased peripheral resistance
- Bronchodilation
- Increased muscle and liver glycogenolysis
- Increased release of glucagon
- Relaxed uterine smooth muscle
Within the sympathetic system we can affect blood pressure by doing what?
- Blocking the beta-1 receptors
- Blocking peripheral alpha-1 receptors
- Trigger central alpha-2 receptors
What does Blocking the beta-1 receptors do?
- Reduce heart rate
- Reduce renin release
What does Blocking peripheral alpha-1 receptors do?
- Vasodilation
- Decreased peripheral resistance
What does Triggering the central alpha-2 receptors do?
Reduce sympathetic outflow to the heart
What are the 3 main Beta Blockers we need to know?
- Carvedilol (CoregTM)
- Metoprolol (LopressorTM, Toprol XL)
- Nebivolol (Bystolic)
What is the prescription for Metoprolol Ext. Rel.?
100 mg
One tablet daily
- Max dose = 400 mg
What is the prescription for Carvedilol?
12.5 mg
One tablet twice a day
What is the prescription for Bystolic™?
20 mg
One tablet daily
- May start at 5 mg and titrate up
What are the differences based on for the Beta Blockers?
Selectivity
What are the 3 categories of Selectivity for the Beta Blockers?
- ) Non-selective beta-blocker:
- Block both beta-1 and beta-2 receptor sites
- Example: propranolol - ) Selective beta-blockers
- Specifically block beta-1 receptors
- Example: metoprolol - ) Beta-blockers with peripheral vasodilatory effects
- Adds in an alpha-1 blockade effect –> Example: labetolol, carvedilol
- Affects nitric oxide levels –> Example: nebivolol
What is Atenolol indicated for?
- Treatment of hypertension, alone or in combination with other agents
- Management of angina pectoris
- Secondary prevention postmyocardial infarction
What is Carvedilol (Coreg™, Coreg CR™)
indicated for?
Management of hypertension
Mild-to-severe heart failure of ischemic or cardiomyopathic origin
Left ventricular dysfunction following myocardial infarction (clinically stable with LVEF ≤40%)
What is Metoprolol succinate (Toprol XL™) indicated for?
Treatment of hypertension
Treatment of angina pectoris
To reduce mortality/hospitalization in patients with heart failure (stable NYHA Class II or III) already receiving ACE inhibitors, diuretics, and/or digoxin
What is Nebivolol (Bystolic™) indicated for?
Treatment of hypertension, alone or in combination with other agents
What is the candidate for use of Beta Blockers?
Younger patients rather than older patients
What is the effectiveness of Beta Blockers?
- No evidence for primary prevention of hypertension
- Preferred agents for patients with cardiac disease
What Agents would require dose adjustments in patients with renal impairment?
Atenolol
What drugs have Hepatic metabolism and need no renal dose adjustment but have first pass effect issues?
Metoprolol, carvedilol
So oral is higher dose than IV
Because of lipid and water solubility and possible penetration of blood brain barrier, Beta Blockers could cause?
Theoretically beta blockers in the CNS would cause effects such as: Lethargy, Nightmares, Confusion, Depression
Beta Blockers that are water soluble have?
- Less tissue penetration
- Longer biological half-lives
Ex: atenolol
What are the Adverse effects of Beta Blockers?
- Many side effects related to effects on cardiac tissue: Bradycardia, Hypotension, Atrioventricular nodal conduction block
- Bronchoconstriction
- Hypoglycemia
What are the Alpha Blockers?
- **Doxazosin (Cardura)
- Prazosin (Minipress)
- Terazosin (Hytrin)
What is the prescription for Doxazosin?
8 mg
One capsule daily
How do the Alpha Blockers work?
o Blockade of alpha-1 receptors
Affect both arteriolar and venous resistance vessels
• Magnitude based on sympathetic system activity
• Body response to fall in blood pressure can be
o Increase in heart rate
o Increase in cardiac output
o Increased fluid retention
What are the Adverse Drug Reactions of the Alpha Blockers?
o Orthostatic hypotension
Increased fall risk
Easing into therapy or dose changes (First dose syncope)
o Aggravators
Nasal congestion, headache, reflex tachycardia, peripheral edema (B/c good at opening up blood vessels)
o Non-selective alpha blockade
Smooth muscles of the base of the urinary bladder
What are the differences between the alpha blockers?
o Biological half life –> Doxazosin has longest half life
What is Prazosin (Minipress) indicated for?
Treatment of hypertension
What is Terazosin (Hytrin) indicated for?
- Management of mild-to-moderate hypertension; alone or in combination with other agents such as diuretics or beta-blockers
- Benign prostate hyperplasia