Drugs to Treat Aortic Dissection Flashcards
Beta blockers work by blocking the effects of?
This has what effect on the heart?
It has what effect on blood flow?
1) Epinephrine
2) Beats more slowly and with less force leading to lower BP
3) Increases
What are common drugs to treat acute aortic dissection?
1) Labetalol
2) Esmolol
3) Nitroprusside
4) Nitrocardipine
Labetalol is typically given as a racemic mixture to achieve?
What does this result in?
1) Blocking of alpha and beta adrenergic receptor activity
2) Decreased peripheral vascular resistance
The FDA-approved indication for labetalol is the treatment of?
Arterial hypertension
What are some warnings and precautions for labetalol? (7)
1) Hepatic injury
2) Cardiac failure
3) Exacerbation of ischemic heart disease following abrupt withdrawal
4) Non-allergic bronchospasm
5) Pheochromocytoma
6) Diabetes mellitus
7) Major surgery
What drug interaction with labetalol will cause tremor?
Which anesthetic has a drug interaction with labetalol?
Which increases the risk of bradycardia?
Which can cause additional antihypertensive effects?
Which calcium antagonists can cause drug interactions?
1) Tricyclic antidepressants
2) Halothane anesthesia
3) Digitalis glycosides
4) Nitroglycerin
5) Verapamil
What special populations should you use caution when administering labetalol?
1) Pregnant women
2) Nursing mothers
3) Geriatric patients
How does pregnancy affect labetalol?
How is it affected in geriatric patients?
1) Increase in clearance due to progesterone so that labetalol concentration falls below therapeutic value
2) Decreases in clearance
Why is IV labetalol the preferred route of administration?
Because of extensive first pass metabolism
The absolute bioavailability of Labetalol is increased when administered with?
The plasma half-life of Labetalol following oral administration is about?
1) Food
2) 6 to 8 hours
What is the distribution of labetalol?
1) Plasma protein binding (50%)
2) Found in breast milk
3) Crosses placenta
The metabolism of labetalol is mainly through?
Within the first 24 hours, approximately 55% to 60% of a dose appears in the urine as?
1) Conjugation to glucuronide metabolites
2) Conjugates or unchanged labetalol
With labetalol administration you should advise patients to consult a physician when there are any signs or symptoms of?
What phenomenon may occur, especially when treatment is initiated?
1) Cardiac failure or hepatic dysfunction
2) Tingling of scalp
What effect does esmolol have on the heart?
Slows heart rate and decreases the BP resulting in increased blood and oxygen to heart
What does it mean that esmolol is a class II antiarrhythmic?
Competitively blocks b1- adrenergic stimulation
What is esmolol indicated for?
Can it be used during or after surgery?
1) Control rapid heartbeats or abnormal heart rhythms
2) Yes
Exposure of esmolol to the fetus may cause?
Fetal bradycardia
Why is esmolol not indicated for the chronic treatment of hypertension?
However, it may be considered as an alternative agent for hypertensive emergencies in?
1) It is a short-acting beta-blocker
2) Pregnancy
With esmolol prescriptions, what may be observed more frequently in elderly patients?
Bradycardia
You should use esmolol with caution in patients with history of?
Severe anaphylaxis to allergens
What do you want to avoid when administering esmolol because it can lead to skin necrosis and sloughing?
Extravasation
Esmolol has been associated with elevations in?
Especially in patients with what risk factor?
1) Serum potassium (Hyperkalemia)
2) Renal impairment
Esmolol has been associated with what occuring during surgery?
How is this corrected?
1) Hypotension
2) Reduce dose or discontinue within 30 minutes
Why is esmolol considered a soft drug?
What is its half-life?
It is rapidly metabolized by?
1) It is rapidly metabolized to an inactive form
2) 9 minutes
3) Hydrolysis of ester linkages from enzymes in cytosol of RBCs
Sodium nitroprusside breaks down in circulation and binds to hemoglobin to release?
1) Nitric oxide
2) Cyanide
3) Methaemoglobin
What does NO released from nitroprusside activate?
This then leads to the increase of intracellular production of?
Which then activates?
Which causes activation of?
This then inactivates?
This then all results in?
1) Guanylate cyclase
2) cGMP
3) Protein kinase G
4) Phosphatases
5) Myosin light chains
6) Vascular smooth muscle relaxation and dilation of blood vessels
Sodium nitroprusside injection is mainly used for?
What effect does it have during surgery?
What effect does it have on acute congestive heart failure?
1) Lowering of BP immediately in adults and children with high blood pressure
2) Reduces bleeding
3) Treats it
Nitroprusside should not be used for what type of HTN?
It should be used with great caution in patients with condition associated with?
1) Compensatory
2) Higher cyanide/thiocyanate ratio
What conditions are contraindicated with nitroprusside due to a higher cyanide/thiocyanate ratio?
1) Congenital (Leber’s) optic atrophy
2) Tobacco Amblyopia (Due to cyanide)
What should be closely monitored when administering nitroprusside to pregnant women?
Maternal pH and cyanide levels
What serious adverse effects are associated with nitroprusside?
1) Cyanide poisoning
2) Thiocyanate toxicity
What should be administered to increase the rate of toxic cyanide processing?
Sodium thiosulfate
One molecule of sodium nitroprusside is metabolized in combination with hemoglobin to produce?
One molecule of cyanmethemoglobin and four CN¯ ions
Patients with impaired renal function will develop what toxicity after prolonged and rapid infusions of nitroprusside?
Thiocyanate
What is the MOA of nicardipine hydrochloride capsules?
Calcium entry blocker
Nicardipine inhibits the transmembrane influx of calcium ions into cardiac muscle and smooth muscle without?
However, the effects are more selective to which of the above?
1) Changing serum calcium concentrations
2) Vascular smooth muscle than cardiac muscle
Nicardipine hydrochloride injection is indicated for the short-term treatment of?
What is used for prolonged control?
1) Hypertension
2) Oral meds
What contraindication is noted with nicardipine?
Patients with advanced aortic stenosis
You want to avoid systemic hypotension when administering nicardipine to patients who have sustained?
Acute cerebral infarction or hemorrhage
Increases in frequency, duration, or severity of what has been seen in chronic therapy with oral nicardipine?
Angina
You want to use nicardipine cautiously particularly in combination with a beta-blocker in patients with heart failure or significant left ventricular dysfunction because of possible?
Negative inotropic effects
You want to use nicardipine cautiously in patients with impaired hepatic function because?
It is metabolized in the liver
What should you do when administering nicardipine in patients with impaired renal function?
Titrate gradually
In general, what should your initial dose of nicardipine be in elderly patients?
Low initial doses
What drugs have interactions with nicardipine due to nicardipine inhibition of hepatic microsomal enzymes?
What is the enzyme?
1) Cyclosporine and tacrolimus
2) CYP3A4
What transporter is involved in the metabolism of nicardipine?
P-gp (MDR1) substrate
