Pharm exam 2 - Adrenergic antagonists

Prototype α1 blocker?

Prazosin

What suffix is commonly seen in α1 blockers?

-osin

What are the therapeutic uses of α1 blockers?

• Essential hypertension
• Benign prostatic hyperplasia (BPH)
• Pheochromocytoma
• Raynaud's disease
• Phentolamine (non-selective): antidote for IV extravasation of α1 agonists

Why are α1 blockers used in BPH?

Relax the prostate and bladder neck

Why are α1 blockers used for renal stones?

Facilitate stone passage

Why are α1 blockers used before surgery for pheochromocytoma?

Pre-op blood pressure control

Why are α1 blockers used in Raynaud’s disease?

Peripheral vasodilation

What can α1 blockers reverse?

α1 agonist overdose/ toxicity

What non-selective α blocker is used as an antidote for IV extravasation of α1 agonists?

Phentolamine

What is the FIRST - DOSE effect of α1 blockers?

Orthostatic hypotension

Dangerous: because increases risk of falls!!!!

Why can α1 blockers cause reflex tachycardia?

Baroreceptor reflex

What are the adverse effects of α1 blockers?

• Orthostatic hypotension

• Reflex tachycardia

• Nasal congestion

• Inhibition of ejaculation

• Sodium and water retention

Why can α1 blockers cause sodium and water retention?

Increase blood volume

What is a non-selective alpha blocker ?

Phentolamine

What is the therapeutic uses of phentolamine?

• Pheochromocytoma

• Treatment of tissue necrosis after extravasation of alpha 1 agonists

How is phentolamine administered for α1 agonist extravasation?

SQ diluted with saline

What are the adverse effects of phentolamine?

• same as alpha 1 antagonists

• significant reflex tachycardia

What may be needed to treat phentolamine-induced reflex tachycardia?

A β-blocker

What do beta blockers end in ?

-lol

1st Generation Propranolol - MOA

Non selective: blocks B1 and B2

1st Generation Propranolol - uses

HTN, angina, dysrhythmias, MI, stage fright

1st Generation Propranolol - adverse effects

bronchoconstriction, decrease glucose clearance, bradycardia, fatigue

2nd Generation Metoprolol- MOA

cardioselective: blocks B1 only

2nd Generation Metoprolol- uses

HTN, angina, dysrhythmias, MI, heart failure

2nd Generation Metoprolol- adverse effects

Bradycardia, fatigue, HF precipitation, rebound excitation if stopped abruptly. Masks
hypoglycemia

3rd Generation Carvedilol - MOA

Non selective: blocks beta 1, beta 2 and alpha 1

3rd Generation Carvedilol - uses

HTN, angina, HF, MI

3rd Generation Carvedilol - adverse effects

All β1, β2, AND α1 adverse effects (orthostatic hypotension, bronchoconstriction)

How many generations of beta blockers are there?

3

Nursing Responsibilities - Beta blockers

• Never stop abruptly – taper to avoid rebound excitation (catecholamine hypersensitivity)
• Hold if HR < 60 bpm or BP < 90/60 – notify provider
• Monitor glucose in diabetic patients (masks hypoglycemia signs: ↑ HR hidden)
• Assess for signs of heart failure worsening (dyspnea, weight gain, edema)
• Educate: do not double-dose if missed; rise slowly to prevent orthostatic hypotension
• Caution with asthma – use only cardioselective agents if necessary