The beta R & HTN

Question 1

MOA for Propranolol?

Answer 1

• Non-selective beta-adrenergic blocker (class II antiarrhythmic); competitively blocks response to beta1 & beta2 stimulation

Question 2

Effects of Propranolol?

Answer 2

• Beta1 blockade –> ↓ HR, myocardial contractility, BP, & myocardial oxygen demand
• Beta2 blockade –> blunting of bronchodilation & vasodilation in sk m

Question 3

Clinical applications for Propranolol?

Answer 3

• HTN
• Angina pectoris
• Pheochromocytoma
• Essential tremo supraventricular arrhythmias
• Ventrical tachycardias
• MI prevention
• Migraine HA prophylaxis
• Off-label: akthisia, anti-psychotic-induced; performance anxiety; thyroid stomer/thyrotoicosis; tremor, lithium-induced

Question 4

PKs of propranolol?

Answer 4

• PO
• ~25% reaches system circulation d/t high first pass metabolism
• ER tablets, oral solutions, & IV solutions available

Question 5

Toxicity of Propranolol?

Answer 5

• Bronchospasm, dyspnea
• Cold extremities –> no beta blockers for peripheral vascular dz
• Brady, AV condxn disturbance, CHF, cardiogenic shock, hypotension, syncope
• Disrupted sleep w/ nightmares, drowsiness/fatigue, agitation
• Hyperglycemia or hypoglycemia; hyperkalemia; HLD
• Abd pain, diarrhea, constipation, etc
• Conjunctival hyperemia, ↓ visual acuity, mydriasis

Question 6

MOA for atenolol?

Answer 6

• Competitive beta1 antagonist
• Little or no effect on beta2 Rs except at high doses

Question 7

Effects of atenolol?

Answer 7

• Beta1 blockade –> ↓ HR, contractility, BP, and myocardial oxygen demand

Question 8

Clinical applications of atenolol?

Answer 8

• HTN (alone or combo)
• • Management of angina pectoris
• Secondary prevention of post-MI
• Off-label: Afib (rate control); pediatric htn; acute EtOH withdrawal (w/ benzo); SV arrhythmias; unstable angina; ventricular arrhythmias

Question 9

PKs of Atenolol?

Answer 9

• PO - rapid, incomplete, ~50% bio-avail
• Not lipophilic, does not cross BBB
• Half life 6-7 hrs, prolonged in renal impairment

Question 10

Toxicities of Atenolol?

Answer 10

• Brady, CF, CP, cold extremities, complete AV block, edema, hypotension, Raynaud’s, second degree AV block
• Confusion, fatigue, HA, insomnia, lethargy, nightmares
• Constipation, diarrhea, nausea
• Impotence

Question 11

Metoprolol?

Answer 11

• Widely used beta1-selective blocker, shorter half life than atenolol but avilanle in ER form; more lipid soluble w/ ↑ risk for adverse CNS effx (lethargy, confusion, nightmares, etc)

Question 12

Bisoprolol

Answer 12

• Has the highest beta1-selectivity