And more drugs Flashcards
Hyperlipidemia Anti-Arrhythmias Only a couple hyperlipidemia..
MOA of statins
inhibits rate-limiting step of cholesterol synthesis, which:
- upregulates LDL receptors in liver
- reduces lipoprotein secretion in liver
Statins reduce…
LDL (50%)
TG (~37%)
(and increase HDL ~15%
Statins are predominately excreted through
feces
-mycin antibiotics, azoles, SSRI’s, CCB’s and grapefruit juice will have drug interactions with these statins:
Atorvastatin (lipitor) and Lovastatin
**via CYP3A4
Cyclosporine and grapefruit juice are contraindicated with statins because they inhibit:
p-glycoprotein mediated intestinal absorption
HMG CoA Reductase Inhibitors adverse effects: (7)
mild GI distress increased liver enzymes sleep disturbance, memory loss teratogenic myalgia without CPK rise myositis with CPK rise rhabdomyolysis with CPK rise
Statin which will have no effect on TG
lovastatins
How do bile acid sequestrants interrupt recycling of cholesterol?
bile negatively charged bile acids in the gut
Group of antilipemic drugs that are non-systemic
bile acid sequestrants
Group of antilipemic drugs that are safe for use in patients with liver disease
bile acid sequestrants
What side effects may limit use of bile acid sequestrants?
GI bloating
constipation
possible increase in TG
Bile acid sequestrants prevent the absorption of what drugs?
digoxin
beta blockers
thyroxine
coumadin
(these should be taken an hour before or 3-4 hours after BAS)
MOA of ezetimibe (zetia):
inhibits absorption of cholesterol in small intestine by 50%, which reduces delivery of cholesterol to liver
this results in upregulation of LDL receptors and increased clearance of LFL from plasma
ezetimibe (zetia) localizes to:
brush border of small intestinal epithelium
Excretion of ezetimibe (zetia):
biliary (78%) and renal
Effect of ezetimibe (zetia) on LDL, HDL, TG:
lowers LDL by ~18%
increased HDL by ~5%
lowers TG by ~11%
Drug interactions associated with ezetimibe (zetia):
- bile acid sequestrants (decrease absorption of ezetimibe by up to 80%)
- cyclosporine (3-4 fold increase in ezetimibe levels)
- fibrates (when combined, may increase biliary cholesterol excretion and increase risk of gallstones)
Most significant side effect associated with ezetimibe (zetia):
increased liver enzymes when co-administered with a statin
MOA of fibric acid derivatives
gemfibrozil and fenofibrate
serves as ligand for ligand-activated PPAR-alpha nuclear receptor, which then causes:
- supresses transcription of ApoCIII (which increases LPL)
- increased ApoA1 synthesis
- increases PL transfer protein activity
- increased FA oxidation (reduces TG synthesis)
- increased biliary cholesterol excretion via increased cholesterol 12a hydroxylase
Effects of fibric acid derivatives on: VLDL TG HDL LDL
VLDL: reduced
TG: reduced by up to 50%
HDL: increased (~15%)
LDL: unchanged/-/+
Side effects of fibric acid derivatives:
GERD, diarrhead increased liver enzymes gallstones teratogenic/embryocidal in animals pregnancy category C
Side effect specific to fenofibrate (tricor):
reversible increase in creatinine
Gemfibrozil reduces metabolism of what drugs?
statins
Gemfibrozil is a good drug choice for patients with…
unlike fenofibrate
renal disease (extensively metabolized by liver)
MOA of niacin: (5)
- inhibits mobilization of FFA from adipocytes
- reduced hepatic TG synthesis
- reduces ApoB synthesis and secretion (VLDL)
- Enhanced ATP cassette-mediated transfer of cholesterol from macrophage to HDL
- Enhances LPL (promotes conversion of VLDL to LDL)
Niacin's effects on: HDL LDL TG Lp(a)
HDL: increased (via increased plasma ApoA1)
LDL: reduced
TG: reduced
Lp(a): reduced *unique feature
Side effects of niacin:
- flushing
- increased liver enzymes, hepatitis, failure
- GI irritation and activation of peptic ulcer disease
- hyperuricemia/gout
- retinal detachment
- cystoid macular edema
- myositis
- skin dryness, etc
- insulin resistance, hyperglycemia
*SMUGGLED
(skin flushed, myositis, uric acid, GI, glu, liver, eyes, dry skin)
Effects of N3FA:
low TG antiplatelet antiarrhythmic reduced BP reduced CAD*
MOA of N3FA:
reduced hepatic TG synthesis by reducing SREBP
increased FA ox via PPAR-alpha activation
Effects of N3FA on:
HDL
LDL
TG
HDL: none
LDL: none
TG: lowers
N3FA is a formulation of ___ and ___
EPA
DHA
Class I antiarrhythmics
Examples?
Na channel blocker
lidocaine, procaine
Class II antiarrhythmics
Examples?
beta blocker
propranolol, metoprolol
Class III antiarrhythmics
Examples?
K channel blocker
amiodarone, sotalol, ibutilide
Class IV antiarrhythmics
Examples?
Ca channel blocker
verapamil, diltiazem
Phase IV depol of the SA node is slowed by
vagal activity (ACh) digoxin
Phase IV depol of the SA node is accelerated by
sympathetic activity class II drugs
Phase 0 depol is slowed by
Ca channel blockers class IV drugs
The cell is hyperpolarized by:
adenosine
Class II drugs are used for:
symptomatic PVC's reducing arrhythmia's post-MI (*survival) reducing enhanced automaticity angina HTN
Class I drugs are used to treat:
how?
enhanced automaticity
blocking NA channels in the fast-conducting ventricular cells reduces membrane responsiveness
=slower recovery
Class I drugs bind to Na channels in the _____ and ______ states
open and inactivated
Class I drugs result in decreased rate of rise of phase ___ depol
0
Procaineamide is a class ___; its dissociation rate is ___ sec and it slows conduction at ___ rates.
IA
>1 sec
slow
Lidocaine is a class ___; its dissociation rate is ___ sec and it slows conduction at ___ rates.
IB
<1 (rapid!)
fast rates (and ischemia)
Flecanide is a class ___; its dissociation rate is ___ sec and has a ______ effect on conduction
IC
>10 sec (very slow)
pronounced
Side effects of procainamide:
drug induced lupus (more likely in slow metabolizers)
tosades de pointes (especially if drug accumulates, as in renal failure)
Procainamide has little effect on:
SA and AV nodes
EP effects of procainamide:
- prolongs AP duration
- suppresses ectopic PM activity in partially depol cells
- reduced conduction velocity
Lidocaine preferentially binds to
Na channels in partially depolarized cells to suppress abnormal automaticity
Lidocaine is effective for use in (atrial/ventricular) arrhythmias
ventricular
How does lidocaines dissociation rate affect its regulation of HR?
because of its rapid dissociation, cells can recover between APs at a NORMAL HR; thus it blocks at high HR
Lidocaine distributes into
fat tissue
Side effects of lidocaine:
CNS, agitation, confusion, seizures
Flecainide is contraindicated in patients with
structural heart disease
proarrhythmic in:
- LV dysfunction
- CHD
- sustained VT
Class III drugs will block phase ___, which prolongs the effective refractory period (or the __ on an EKG).
3
QT
Prolonging effective refractory period in the slow conducting limb prevents:
re-entry
Amiodarone blocks what channels?
K
Na
Ca
beta-adrenergic
Amiodarone slows what portions of an EKG?
PR
QRS
QT
(also causes sinus bradycardia)
IV amiodarone is used to treat:
life-threatening arrhythmias
used in cardiac resuscitation
amiodarone is metabolized via
What does it interact with?
CYP3A4
digoxin
warfarin
Side effects of amiodarone:
pulmonary fibrosis photosensitivity dermatitis corneal halos optic neuritis (possible blindness) hypo/hyperthyroidism muscle weakness hepatitis
Sotalol blocks what channels?
K
beta (in L isomer)
Sotalol is excreted via
kidneys
Sotalol is contraindicated in:
prolonged QT renal insufficiency Asthma/COPD decompensated CHF 2nd/3rd AV block sinus bradycardia
Not so awesome sotalol side effect:
torsades de pointe
Indicated for acute termination of a-fib or a-flutter
ibutilide
“Pure” class II drug
ibutilide
Major side effects of ibutilide
transient asystole
torsade de pointes (polymorph V-tach)
Antiarrhythmics that block __ channels have torsade de pointes as a side effect
K
Drugs that treat v-tach
- amiodarone
- lidocaine (IV)
- procaineamide
Sotolol should not be given in the setting of:
acute MI
Drugs that block conduction through the AV node are used to control:
rapid supraventricular arrhythmia
Drugs that slow conduction through AV node:
- verapamil (class IV CCBs)
- propranolol (class II, beta-blockers)
- digoxin
Drugs that will have NO effect on AV node:
procaineamide, lidocaine, ibutilide
Effects of class IV drugs:
reduced SA node automaticity
reduced AV node conduction
Adverse effects of class IV drugs:
SA/AV block
impaired myocardial contractility
hypotension
Class IV are useful in what type of patients?
Contraindicated in?
can’t tolerate beta-blockers
normal LV function
CHF
LV dysfunction
Sinus bradycardia
AV block
Effects of digoxin
increases vagal activity to reduce SA automaticity
inhibits Na/K/ATPase, which results in Ca overload
Drug that terminates paroxysmal supraventricular tachycardia
adenosine
Common adenosine side effects:
chest tightness
transient asystole
flushing
recurrent PSVT without additional trx
What drug can be diagnostic for PSVT?
adenosine: if that fixes it = PSVT;
if not, try again
Digoxin alone is contraindicated in patients with:
WPW
can induce vfib
What drug class inactivates bradykinin?
ACEI
Side effects of ACEI’s:
Hypotension Azotemia (volume-reduced, reduced GFR) Cough (Bradykinin) Angioedema (Bradykinin) Skin rash Dysguesia (“metallic” taste) Hyperkalemia--may affect renal function
ACEI or ARB’s: which is preferred in CHF?
ACEI
How do beta blockers affect CHF patients?
short term not so great, but long term increases CO and decreases LVEDP
What molecular effects do beta blockers have in CHF?
- Reverse desensitization
- Increase receptor number
- Restore fast signaling modes (contractility) over slow signaling modes (gene expression)
Beta blockers approved for CHF
Metoprolol (Lopressor®, Toprol XL®)
Carvedilol (Coreg®)
Bisoprolol (Zebeta®)
***NOT nebivolol
Digoxin will ___ contractility and ___CO
increase
increase
ACEI and ARB prevent/reverse the mitogenic effects of AngII, which include:
hypertrophy of cardiac myocytes and vasc smooth musc
cardiac and vasc fibrosis
atherosclerosis
What type of duiretic should you use with ACEI?
K sparing (like spironolactone)
Do not give which 3 drugs with digoxin?
quinidine (decr elim)
amiodarone (decr elim)
verapamil (slowing of HR)