Shared Flashcard Set

Details

calcium channal blockers
calcium channal blockers
101
Pharmacology
06/06/2011

Additional Pharmacology Flashcards

 


 

Cards

Term
What are the two categories of CCBs?
Definition
nondihydropyridines (NDH) and dihydropyridines (DH)
Term
The catagories of CCB are based on the drug's predominant___________.
Definition
physiologic effects
Term
nondihydropyridine (NDH)reduce ________ and affect cardiac ______ & ______.
Definition
reduce permeability
affect cardiac contractility and conduction
Term
Dihydropyridine (DH) vaso_____.
Definition
dilate
Term
DH generally have neutral or increased effects on vascular __________.
Definition
permeability
Term
What are two examples of NDHs?
Definition
verapamil and diltiazem
Term
This NDH is dosed at bedtime, PO or IV and can be given up to QID.
Definition
verapamil
Term
This NDH is dosed daily and is as known as Cardizem?
Definition
diltiazem
Term
What are some examples of Dihydropyridines (DH)?
Definition
"-pine": amlodipine (norvasc), Nicardipine (cardene), Clevidipine (cleviprex)
Term
What effect do CCBs have on myocardial oxygen demand and blood sypply?
Definition
decreases myocardial oxygen demand
increase myocardial blood sypply
Term
T/F: CCBs inhibit smooth muscle contration via dilating blood vessels and decreasing resistance to blood flow.
Definition
True
Term
CCBs dilate peripheral vessels. What is the effect of dilation?
Definition
decreased SVR, BP, and SVR...leading to decreased workload for the heart
Term
What do CCBs do that improves coronary blood flow?
Definition
coronary artery dilation
Term
Verapamil and Diltizem have what effect on contraction?
Definition
decrease myocardial contractile force leading to a negative inotropic effect
Term
Verapamil and Diltiazem delay impulse transmission through the ___ node by direct action.
Definition
AV node
Term
Nifedipine is a potent ____ vasodilator to create marked decrease in PVR.
Definition
arterial
Term
By decreasing PVR, Nifedipine reflexly stimulates the _______, leading to a slight increase in HR and may increase myocardial oxygen demand.
Definition
SNS
Term
Verapamil and Diltiazem is able to prevent reflex tachy through this mechanism.
Definition
cardiodepressant effects
Term
Why might verapamil and diltiazem not be indicated for a pt with CHF?
Definition
they are more likely to worsen ventricular function in pt with CHF, leading to systolic dysfunction
Term
What are the five componets to the MOA of CCBs?
Definition
1) inhibit the L-type Ca channel
2) bind to receptors
3) decrease in transmembrane Ca current
4) decrease sinus node conduction velocity
5) decrease AV node conduction velocity
Term
Where are L-type Ca channels present?
Definition
cardiac and smooth muscle
Term
By binding to receptors, CCBs convert this function of the channel.
Definition
convert the mode of operation of the channel
Term
What is the result of decreasing the transmembrane Ca current?
Definition
smooth muscle relaxation and reduction in contractility throughout the heart
Term
Vascular smooth muscle normally has high OR low intracellular Ca?
Definition
low
Term
smooth muscle contrations depends on an _______ of extracellular Ca through Ca channels located on the cell _______.
Definition
smooth muscle contraction depends on an INFLUX of extracellular Ca through Ca channels located on the cell MEMBRANE.
Term
Pharmacologic effects of Verapamil
Definition
Peripheral Vasodilation: increased!!
HR: decrease!!!
Contractility: decrease!!
SA/AV conduction: decrease!!
Coronary vasodilation: increase!!
Term
Pharmacologic effects of Diltiazem
Definition
Peripherial vasodilation: increase!!
HR: decrease!!
contractility: decrease
SA/AV conducion: decrease
Coronary vasodialtion: increase!!!
Term
Pharmacologic effects of dihydrophyridines (DH)
Definition
peripheral vasodilation: increase!!!
HR: increase/no effect
contractility: decrease/no effect
SA/AV conduction: no effect
Coronary vasodilation: increase!!!
Term
what four areas of organ systems effects of seen with CCBs?
Definition
smooth, cardiac, and skeletal muscle effects, along with cerebral vasospasm
Term
T/F: Most types of smooth muscle are dependent on transmembrane Ca EFLUX for normal resting tone and contaractile responses?
Definition
False: Ca INFLUX
Term
CCBs ______ smooth muscle
Definition
relax
Term
In regards to arteries over veins, vascular smooth muscle is _______ sensitive to CCBs.
Definition
most sensitive
some activity is seen in broncholar, GI, and uterine smooth muscle
Term
Cardiac muscle is highly dependent upon Ca influx for normal function. What do verapamil and diltiazem do to cardiac muscle?
Definition
they interact kinetically with the Ca channel receptor in a different manner than the dihydropyridines and block tachy in the Ca dependent cells more selectively
Term
Is there an affect on skeletal muscle?
Definition
not affected, although Verapamil does prolong muscle paralysis (vecuronium)
Term
Cerebral vasospams and infarcts following SAH are treated with this drug
Definition
Nimodipine
Term
How does nimodipine work(SAH and ruptured cerebral aneurysms)?
Definition
increases lipophilicity and cerebrovascular selectivity to improve outcomes due to cerebral artery spasm and subsequent neurologic deficits
Term
What organ metabolizes CCBs?
Definition
liver
Term
If a patient has renal impairment: what is their CLcr and what % of the normal dose of Verapamil should be given
Definition
CLcr < 10 (likely on dialysis)
Dose: 50-75% dose
Term
Is it okay to use diltiazem with active renal impairment?
Definition
use with caution (may start with 50% of the normal dose)
Term
If a patient has hepatic impairement what cautions should be taken with verapamil?
Definition
reduce dose to 20-50% of normal and monitor ECG
Term
What are the 5 clinical uses of CCBs?
Definition
HTN
SVT
Coronary artery vasospasm
angina
cerebral artery vasospasm
Term
Verapamil is a nondihydropyridine. What are its uses?
Definition
angina (vasospastic, angina perctoris, and unstable)
arrhythmias: A fib or flutter and PSVT
HTN
HA prevention
CHF (diastolic dysfunction)
Bipolar (manic manifestations)
Term
True/False: Oral Verapamil IR would take 6-8 hours to have effect?
Definition
false: 1-2 hours
Term
What are some contraindications to Verapamil?
Definition
a fib or flutter
CHF
cardiogenic shock
hypersensitivity to CCBs
symptomatic HYPOtension (SBP <90)
2nd or 3rd degree heart block
ventricular tachycardia, wide-complex (QRS >/= 1.2 sec)
Term
When using Verapamil, what might be seen with combining inhalation anesthetics with its administration?
Definition
decrease in INFLUX of Ca ions
depressed cardiovasculature (may be excessive if not titrating each carefully)
Term
What drug is absolutely contraindicated with the concomitant administration of verapamil?
Definition
Dofetilide (Tikosyn)
Term
When giving Verapamil with Dofetilide (Tikosyn) what will be seen with plasma levels of dofetilide and what may occur?
Definition
43% increase in plasma levels can cause serious ventricular arrhythmias (QT prolongation and/or torsades)
Term
if a patient is taking an ACE inhibitor, diuretic, or beta blocker (oral anti-HTN agents), what symptoms may be seen?
Definition
an additive effect on lowing BP and HR
Term
Chronic verapamile treatment can increase these levels 50-75% during the first week?
Definition
Digoxin (doses must be properly adjusted to be well tolerated)
Term
Why would you monitor for signs of midazolam toxity if your patient is taking verapamil?
Definition
midazolam dosage reductions of up to 50% are suggested
Term
Why is it a concern to use verapamil with an HMG Co-A reductase inhibitor?
Definition
verapamil is an inhibitor of CYP 3A4 (simvastatin, lovastatin and atorvastatin are metabolized by CYP 3A4 adn these levels may be increased and place the pt at risk for toxicity)
Term
What are some contraindications to the use of Diltiazem?
Definition
AMI with pulmonary congestion
recent use of IV beta-blockers
newborns (IV only r/t alcohol contents)
ventricular tachy/fib(IV only)
a fib/flutter causing fatal HR changes
cardiogenic shock
heart block
symptomatic BP SSS without a venticular pacemaker
Term
What are the uses for Diltiazem?
Definition
Like Verapamil:
angina (vasospastic, angina perctoris, and unstable)
arrhythmias: A fib or flutter and PSVT
HTN
HA prevention
CHF (diastolic dysfunction)
Bipolar (manic manifestations)
Term
True/False: Diltiazem PO has a faster onset than Verapamil?
Definition
True: 30-60 min vs. 1-2 hours
Term
What drugs interact with Diltiazem?
Definition
cyclosporine, carbamazepine,cimetidine, alfentanil, sufentanil, remifentanil, fentanyl, amiodarone, atazanavir(reyataz), enflurane, beta blocker, midazolam, digoxin, HMG Co-A reductase inhibitor
Term
What must happen to maintain cyclosporine trough levels similar to those prior to the addition of diltiazem?
Definition
a reduction of 15-48%
Term
What may be seem with carbamazepine if given with diltiazem?
Definition
toxicity r/t elevated plasma levels (40-72%)
Term
Cimetidine use with have what effect on diltiazem plasma levels?
Definition
increase in peak levels (58%) and area-under-the curve (35%) after 1 week course of cimetidine
Term
What is increased when alfentanil and diltiazem interact?
Definition
alfentanil's half-life increases by 50%, CNS depressant time
Term
What enzyme is inhibited by diltiazem that metabolizes alfentanil?
Definition
CYP P450 3A4 enzymes
Term
When giving alfentanil, should you reduce its dose or the dose of diltiazem?
Definition
dose of alfentanil may be reduced
Term
When giving verapamil or diltiazem these pain treatments may enhance bradycardic effects and hypotensive effects?
Definition
alfentanil, sufentanil, remifentanil, and fentanyl
Term
What may result if amiodarone is given with diltiazem?
Definition
brady, AV block and/or sinus arrest
Term
Does amiodarone inhibit CYP 450 3A4?
Definition
yes
Term
What may occur if atazanavir (reyataz) is given with diltiazem and which drug shoudl be decreased in doseage?
Definition
cardiotoxicity (prolonged PR interval), inhibition of diltiazem metabolism (CYP3A)
Decrease diltiazem dose by 50%
Term
This inhaled anesthesic, when given with diltiazem, may result in additive depressant effect on AV nodal conduction and sinus node function?
Definition
enflurane
Term
If you use CCBs, Beta blockers, and fentanyl what may happen to pt's BP?
Definition
severe hypotension
Term
What may occur if you use a beta blocker with diltiazem?
Definition
hypotension, LVF, and AV disturbances
Term
How much should the dose of midazolam be reduced when using diltiazem?
Definition
50% and monitor for toxicity
Term
True/False: when using diltiazem with digoxin there may be a 50% DECREASE in serum digoxin concentrations?
Definition
False: 50% increase in digoxin
Term
What will happen to the levels of HMG Co-A reductase inhibitors when used with diltiazem?
Definition
level can be increased, placing the pt at risk for toxicity
Term
how are dihydropyridines (DH) categorized?
Definition
based upon half-life and effect on contractility
Term
what is a short-acting PO DH?
Definition
nifedipine (capsule containing liquid)
Term
with is a short-acting injectable DH?
Definition
clevidipine
Term
What is the cardiac response to a longer-acting DH?
Definition
little cardiac depressant activity: felodipine, isradipine, nicardipine, nifedipine gtts and CC, and nisoldipine
Term
What longer-acting DH has no cardiac depressant activity?
Definition
amlodipine
Term
What are the uses of dihyropyridines (DH)?
Definition
angina
HTN
renal protection in diabetics
cerebral spasm r/t SAH (nimodipine)
raynaud's phenomenon (nifedipine)
Term
What patients need to take precaution with the use of DH?
Definition
CHF
hypersensitivity to CCB
SBP axacerbated angina
liver impairment
aortic stenosis
defective lipid metabolism (clevidipine is in a lipid diluent)
Term
Should you use Nifedipine for HTN urgencies?
Definition
NO! Its use may be associated with severe hypotension, cerebral ischemia, AMI, fetal distress, conduction abnormalities and death
Term
The FDA indicates that Clevidipine (Cleviprex) may be used for what instances?
Definition
reduction of BP when oral therapy is not feasible or desireable and is shown effective in perioperative control of BP an din patients with severe HTN
SE: HA, N/V, A fib
Term
How soon can you double your initial IV dose of Clevidipine?
Definition
double dose in 90 second intervals
Term
Once you meet your BP goal, reduce the dose to < 2 times the dose what should the time between adjustments be increased to?
Definition
5-10 minutes
Term
What is the max dose of clevidipine in a 24 hour period and why?
Definition
max of 1000ml dose due to lipid load restriction
Term
How would you know if your clevidipine has reached an effective onset?
Definition
there would be a 3-5% decrease in SBP
Term
How long does it usually take to see a 15% decrease in SBP in a perioperative pt who has just recieved clevidipine?
Definition
an average of 6 minutes
Term
If you do not transition a pt to oral clevidipine, what may be seen?
Definition
rebound HTN after 72 hours
Term
When should you expect to see BP return to baseline after stopping a clevidipine infusion?
Definition
5-15 minutes
Term
How long is a clavidipine vial viable after the stopper has been punctured?
Definition
4 hours
Term
what drugs interact with dihydropyridines (DH)?
Definition
beta blockers, cimetidine, cyclosprine, digoxin, fentanyl, triazole antifungals and imidazole antifungals
Term
What may be seen when using DH with a beta blocker?
Definition
hypotension or impair cardiac performance
Term
True/False: cimetidine may cause serum level elevations for most avaiable CCBs?
Definition
true
Term
True/False: Cimetidine is most contraindicated with nifedipine and diltiazaem r/t hemodynamic responses?
Definition
true
Term
IF you give cyclosprine with nifidipine you should expect to see an elevation in which drugs levels?
Definition
nifedipine
Term
Minimal effects on cyclosporine blood levels are seen when given with what three drugs?
Definition
nifedipine, isradipine, and nitrendipine
Term
What age group is at most risk for ginigival hyperplasia when using cyclosporine and nifedipine?
Definition
children
Term
What is significant to remeber when taking digoxin with CCBs (nigedipine, diltiazem, nicardipine, verapamil?
Definition
serum digoxin level increase by 50%
Term
The increase seen in digoxin serum levels when taking a CCB is dependent on what?
Definition
the dose of the CCB
Term
What group of pt's are at highest risk for digoxin toxicity when taking a CCB?
Definition
those with a higher pre-existing serum digoxin concentration
Term
If a pt were to be given a CCB or beta blocker while undergoing fentanyl anesthesia would they develope HTN or hypotension?
Definition
severe hypotension
Term
What is key when administering an antifungal to a pt on dihydropyridine CCBs?
Definition
antifungals inhibit CYP3A4 which is responsible for the metabolism of these CCBs and you may need to decrease the dose of your CCB due to the decreased metabolism
Term
When using a CCB and an antifungal what effects may be seen?
Definition
substantial peripheral edema and/or elevated CCB serum levels