Pharmacology - Antihypertensives and Inotropes Flashcards
Class: Clonidine
alpha-2 agonist
Anti-hypertensive
Class: Methyldopa
alpha-2 agonist
Anti-hypertensive
What is the effect of alpha-2 stimulation, as caused by drugs like clonidine and methyldopa?
Decrease in sympathetic outflow;
Decrease in TPR and HR (because lowers NE, therefore indirect effects to lower alpha 1 and beta 1 effects)
Use:
Clonidine
Methyldopa
Mild to moderate HTN
*use methyldopa for HTN in pregnancy
Unique application: Clonidine
Opiate withdrawal
Side effects:
Clonidine
Methyldopa
Rebound HTN is stopped abruptly;
edema
CNS depression
Class: Reserpine
Ganglion-blocking agent
Anti-hypertensive
MOA: Reserpine
Destroys vesicles for NE, dopamine, serotinin
Use: Reserpine
Not used anymore bc of SE (suicide);
Decreases CO and systemic vascular resistance
What is a common side effect of antihypertensives and why?
Edema
Bc lower BP –> activate renin-angiotensin system
Class: Doxazosin (Prazosin and Terazosin also…)
alpha-1 blockers
Use: Doxazosin (Prazosin and Terazosin also…)
Decreases arteriolar and venous resistance –> causes reflex tachycardia;
BPH (decrease tone or urinary sphincter);
Second-tier medication for HTN, use when other conditions exits
What re the only class of anti-hypertensives associated with reflex tachycardia?
Alpha-1 blockers (causes worsening of angina)
Side effects: Doxazosin (Prazosin and Terazosin also…)
Orthostatic hypotension (bc venous resistance down), “first-dose syncope”;
edema;
worsening angina due to reflex tachycardia
Class: Esmolol
Beta-1 selective blocker
Use: Esmolol
AV nodal blockade in unstable pts
Esmolol is know for having what characteristic?
Beta-1 selective blocker;
Short half-life
Class: Hydralazine
Direct-acting vasodilator
Anti-hypertensive
Class: Minoxidil
Direct-acting vasodilator
Anti-hypertensive
MOA:
Hydralazine
Minoxidil
Decreases TPR via arteriolar dilation
Hydralazine - acts through NO
Minozidil - opens K channels
Use: Hydralazine
Moderate to severe HTN;
patients with both advanced CHF and hypertension
What is a unique side effect of hydralazine?
Can cause drug-induced SLE
Use: Minoxidil
Hair loss;
Refractory HTN
Side Effects: Hydralazine
Reflex tachycardia;
Edema;
Drug-induced SLE (high protein binding)
Can hydralazine be used in pregnancy to treat HTN?
Yes
Class: Verapimil and Diltiazem
Anti-arrhythmics AND
Anti-hypertensives
MOA: Verapimil and Diltiazem
Block L-type Ca channels
**good tropism for the heart
Use: Verapimil and Diltiazem
HTN;
Anti-anginal effect (decrease myocardial O2 demand);
SVT (because class IV anti-arrhythmic)
Side effects: Verapimil and Diltiazem
Edema in legs; Bradycardia; AV nodal blockade (bc reduced chronotropy); Hypotention; Worsening HF; Constipation (Ca channels in gut)
In what conditions are Verapimil and Diltiazem contraindicated?
Decompensated HF;
Bradycardia;
SA dysfunction;
High-degree AV block
**Same contraindications for amlodipine, nifedipine
How are verapimil, diltiazem and amlodipine/nifedipine similar?
They are all Ca channel blockers. They exist on a spectrum based on their tropism. Verapimil has the most cardioselectivity (non-dihydropyridine) –> Diltiazem –> Amlodipine and Nifedipine (dihydropyridine). The latter two have tropism for blood vessels
Class: amlodipine, nifedipine
Ca channel blockers
Anti-hypertensives (dihydropyridine)
Use: amlodipine, nifedipine
Hypertension;
Raynaud’s;
3rd choice drug for angina (bc they work better in the vasculature than the heart)
Side effects: amlodipine, nifedipine
leg edema, HF AV nodal blockade, ***reflex tachycardia; constipation; gingival hyperplasia (like phenytoin)
What is the role of renin (kidney)?
Catalyzes angiotensinogen –> angiotensin I
What is the role of ACE (plasma)?
Catalyzes angiotensin I –> angiotensin II
What is the effect of angiotensin II on the adrenal cortex?
Increased aldosterone secretion