Antihypertensive Drugs Ch. 11 (Exam III) Flashcards
What is the formula for MAP?
dBP + 1/3(sBP - dBP)
What 4 factors affect blood pressure?
- Peripheral Resistance
- Vessel Elasticity
- Blood Volume
- Cardiac Output
Briefly describe Frank-Starlings law?
Increase stretch of cardiac muscle = increased Cardiac Output
What is the hydraulic equation of blood pressure?
BP = CO x SVR
What are the 3 main sources of Systemic Vascular Resistance (SVR) ?
What are the sub-factors governing each of these?
- Blood Vessel Diameter (α-agonism/antagonism)
- Blood Viscosity (dehydration, hyperlipidemia, etc.)
- Total Vessel Length (Obesity = more blood vessels)
What is the most common cardiovascular disease?
Primary Hypertension
How can blood pressure be modulated at the vasomotor center of the brain?
What are some drug examples?
Centrally Acting α-2 drugs.
- Methyldopa
- Clonidine
- Dexmedetomidine
Describe the process of the renal response to hypotension ending in angiotensin II formation.
- Hypotension → Renin Release
- Renin → angiotensinogen → angiotensin 1
- angiotensin 1 → ACE → angiotensin 2
How does Angiotensin II modulate blood pressure?
- Arteriole Constriction
- ↑ Aldosterone secretion in adrenal cortex
In what three ways, discussed in lecture, can the RAAS system be altered by drugs?
- Aliskiren inhibiting Renin
- ACE Inhibitors
- ARBs
What endogenous molecule of the RAAS has negative feedback capability on renin release?
Angiotensin II
What are the 4 target sites for blood pressure modulation?
- Heart
- Arteries
- Veins
- Kidneys
How do sympathoplegics treat HTN?
↓ SVR, ↓ CO
What drug class is first-line therapy for treating HTN?
How much of a BP reduction is usually noted with these?
What is the most common toxic side effect?
- Diuretics
- 10-15 mmHg reduction
- Hypokalemia
What is the mechanism of action of Clonidine and Methyldopa?
Both act on α-2 receptors of the Tractus Solaris and Rostral Ventrolateral Medulla to ↑ PSNS and ↓ SNS.
Is methyldopa a prodrug?
If so, what are it’s active metabolites?
Yes.
Methyldopa → α-methyldopamine + α-methylNE
Does methyldopa cross the BBB?
Yes
What is methyldopa used for? Why?
What is the primary side effect of methyldopa?
- Pregnancy induced hypertension.
- Methyldopa does not cross the placenta.
- Sedation.
Which centrally acting sympathoplegic is a partial agonist?
What does this drug do to blood pressure?
Clonidine
Slight initial ↑ BP from α-1.
Prolonged ↓ BP from α-2.
Is Clonidine a first-line therapeutic for HTN?
What are the primary side effects from clonidine?
No
Sedation and dry mouth
What are more common uses for clonidine outside of HTN?
- ADHD (↓ NE in frontal cortex)
- Tourettes
- Withdrawal symptoms
What off-label uses are there for clonidine? Which is most pertinent to CRNA’s?
Anxiety, PTSD
Prolongation of Anesthesia
Which β-blocker is considered the 1st?
Is this drug cardio-selective?
Propanolol
No, affects all β receptors.