Sympathomimetics

Question 1

Beta Blockers

Answer 1

• Decrease CO by blockig sympathetic neural stimulation of B1 adrenergic receptors
• Affects receptors in SA node and cardiac myocytes
• Beta 2 receptors medicate bronchodilation and hepatic release of glucose (Can cause SE)
• Fifth line for treating hypertension

Question 2

Beta Blocker SE

Answer 2

• Prevents bronchodilation in the lungs

- Prevents glycogen breakdown in liver causing glucose release

Question 3

Non-Cardioselective Beta Blockers

Answer 3

• Carvedilol (Coreg) - alpha 1 antagonism
• Labetalol (Normodyne) - alpha 1 antagonism
• Propranolol (Inderal) - alpha 1 antagonist
• Nadolol
• Timolol
• Pindolol - ISA
• Penbutolol - ISA

Question 4

Cardioselective Beta Blockers (B1 > B2)

Answer 4

• Atenolol (Tenomin)
• Bisoprolol (Zebeta)
• Metoprolol (Lopressor, Toprol)
• Nebivolol (Bystolic)
• Acebutolol - ISA
• Betaxolol
• Esmolol (IV only)

Question 5

Special Populations

Answer 5

• Diabetics (severe) - may prevent glucose release between meals
• Asthmatics/COPD (severe) - may prevent relaxation of bronchial smooth muscle and aggravate symptoms of obstructive lung disease (increases asthma attack severity)
• With BOTH groups, pkay to prescribe if only suffering from a mild to moderate form

Question 6

Additional Targets

Answer 6

• alpha 1/Beta 1 and 2 Antagonists
• EX: carvediolol and labetalol
• Decreases CO by beta 1 antagonism
• Decreases PVR by alpha 1 antagonism dilating arterioles and veins (potent vasodilation)

Question 7

ISA

Answer 7

• Intrinsic Sympathomimetic Activity
• EX: Acebutolol, Pinodolol, Penbutolol
• Weak beta blockers = partial agonists
• Weakly stimulate beta receptors when a person is at REST, antagonists when ACTIVE

Question 8

Common SE

Answer 8

• Lethargy and fatigue: decreases exercise tolerance from beta 2 blockade in skeletal blood vessels
• CNS: nightmares (possibly connected to lipophilicity), highest are propranolol, carvedilol, nebivolol

Question 9

Best for pregnancy

Answer 9

Labetolol (Category C)

Question 10

EXTREME CAUTION….

Answer 10

• Severe asthmatics/COPD
• Abrupt D/C - can worsen angina and increase AMI risk
• Life-threatening bradyarrhythmias: AV node conduction defects, patients on verapamil or diltiazem

Question 11

Prazosin/Terazosin (Hytrin)/Doxazosin (Cardura)

Answer 11

• Target: Alpha 1 antagonists
• Action: Lowers PVR
• Location: Blocks epi. at arterioles and veins
• Uses for resistant HTN
• SE: orthostatic hypotension

Question 12

Methyldopa/Clonidine (Catapres)/Guanabenz/Guanfacine

Answer 12

• Target: Alpha 2 agonists
• Action: Lowers CO and PVR
• Location: Blocks sympathetic flow at the brainstem
• Use: resistant HTN (preggo HTN for methyldopa ONLY)
• SE: sedation, dry mouth, sleep disturbances, depression