Week 12 - Alpha-2 Agonists

Question 1

Clonidine (Catapres): indications

Answer 1

HTN, ADHD

Question 2

Clonidine (Catapres): MOA - HTN

Answer 2

Stimulates alpha-2 receptors in the brainstem activating an inhibitory neuron –> reduced sympathetic outflow from CNS –> decreased peripheral resistance, HR, BP, renal vascular resistance

Question 3

Clonidine (Catapres): MOA - ADHD

Answer 3

MOA unknown

Thought that it regulates activity in the prefrontal cortex responsible for emotions, attention, and behaviors

Question 4

Clonidine (Catapres): caution and contraindications

Answer 4

• Do not stop abruptly
• Caution w/ severe coronary insufficiency
• Avoid in those at risk or w/ history of bradycardia
• Caution in renal impairment
• Caution in cerebrovascular disease
• Caution in elderly (BEERs list)

Question 5

Clonidine (Catapres): ADR

Answer 5

Drowsiness, HA, fatigue, dizziness, skin rash, xerostomia, bradycardia, nightmares, constipation, impotence

Question 6

Methyldopa: indications

Answer 6

HTN

Question 7

Methyldopa: MOA

Answer 7

Stimulation of central alpha-2 receptors by methyldopa’s metabolite (alpha-methylnorepinephrine) which produces a decrease in sympathetic outflow to the heart, kidneys, and blood vessels

Question 8

Methyldopa: caution and contraindications

Answer 8

• Caution w/ severe coronary insufficiency
• Avoid in those at risk or w/ history of bradycardia
• Caution in renal impairment
• Avoid in active liver disease
• Caution in cerebrovascular disease
• Caution in elderly

Question 9

Methyldopa: ADR

Answer 9

Edema, sedation, bradycardia, hypotension, skin rash, myalgias, elevated LFTs

Rare: hemolytic anemia, hepatotoxicity

Question 10

What can alpha-2 receptor activation help with?

Answer 10

HTN

Question 11

General MOA of alpha-2 agonists

Answer 11

Slows HR and causes vasodilation by working centrally in the brain