Week 1 Cardiac Pharm 3 of 4 Flashcards
Dose of Ephedrine?
ppt states 5-25mg
BUT
Hammon in lecture states in practice you will see 5-10mg at a time, that the ppt dose is a bit high for a one time dose. (decide for yourself lol)
Onset/duration of Ephedrine?
Immediate; 15 min to 1.5 hours depending on dose.
Why should you use ephedrine cautiously in patients with questionable coronary perfusion?
d/t myocardial oxygen consumption may be more dramatically increased as a result of positive inotropic effect
What may develop with subsequent dosing of ephedrine?
As with any indirect-acting agent, tachyphylaxis may develop with subsequent dosing b/c catecholamine stores become depleted.
What type of drug is clonidine? (class)
Presynaptic Alpha-2 Agonist
What does clonidine cause? (more scientific and detailed explaination)
Stimulation of peripheral presynaptic alpha 2 receptor causes inhibition of catecholamine release with subsequent vasodilation.
Would you use clonidine short term or long term?
Usually used as a short term drug for severe hypertension as an add-on drug.
What occurs if you abruptly stop clonidine use?
Rebound hypertension happens with abrupt stopping of the drug. The resultant increase in catecholamine levels manifests as Tachy and Hptn
if you agonize central alpha 2 receptors (such as with clonidine) it will cause antihypertension, this also results in diminished sympathetic outflow and a resultant decrease in circulating what and what activity?
esultant decrease in circulating catecholamines and renin activity.
If someone is on clonidine then what does this mean for medication continuation throughout the perioperative period?
Continuing medication throughout the perioperative period is essential.
Would you ever taper a clonidine dose or d/c it prior to surgery?
Tapering dose and dc may OCCASIONALLY be indicated prior to surgery.
What could you use during a surgery to prevent withdrawal from clonidine?
Patches may be used during surgery to prevent withdrawal.
What are four other uses of clonidine that is not to lower blood pressure?
Premedicant sedative
Analgesic combined with opiates for epidural treatment of severe pain
Suppression of alcohol withdrawal symptoms
Used as a catecholamine suppression test in diagnosis of pheochromocytoma
ALPHA RECEPTOR ANTAGONISTS: used to treat what kind of issues?
HPTN BPH PHEOCHROMOCYTOMA RAYNAUD’S PHENOMENON ERGOT ALKALOID TOXICITY
Common side effects of alpha receptor antagonist?
Orthostatic hypotension
Baroreceptor mediated reflex tachy
Would you use an alpha receptor antagonist for treatment of emergent hypertension?
They have significantly longer duration of action making it unpredictable and other agents are considered in the treatment of emergent hypertension.
Tell me some medications that are alpha 1 receptor antagonists?
Prazosin (Minipress), doxazosin (Cardura), an terazosin (Hytrin)
Are selective alpha 1 receptor antagonists used for acute or chronic treatment of hypertension?
Selective alpha 1 antagonist used for chronic tx of hptn.
If the alpha receptor antagonist lacks alpha 2 blocking abilities (such is the case with selective alpha 1 antagonists) then they have no effect on what levels?
no effect on norepinephrine levels.
(remember that alpha 2 receptors are what reabsorb norepi from the junction causing it not to be released as much and lowering blood pressure.)
What two types of alpha receptor antagonists are there? (broad classes)
selective alpha 1 antagonists and non-selective alpha antagonists
Which type of alpha receptor antagonist was chosen if there is less norepinephrine induced tachycardia?
selective alpha 1 antagonist was chosen bc non selective alpha antagonists have more norepinephrine induced tachycardia. (see slide 41 if this is confusing)
Which alpha receptor antagonist induces vasodilation in both arterioles and veins?
Prazosin
What can be a major side effect of alpha receptor antagonist use?
Orthostatic hypotension can be major side effect.
True or False
The use of alpha receptor antagonists will only decrease preload?
False
PVR (peripheral) and preload/afterload are diminished.
