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Pharmacology: Drugs for Cardiovascular-Related Conditions (Module 6 Study Guide)

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Inhibiting re-absorption of kidney. When sodium is excreted, water follows.
Most diuretics work by...
Edema; hypertension; congestive heart failure
Which medical conditions benefit from an increase in diuresis; i.e., reducing the volume of water or blood volume is important in which situations?
HCTZ, or hydrochlorothiazide - increases the excretion of Na+, water, Cl-, K+ and bicarbonate (HCO3-)
Name the mild diuretic that is often used as a first choice for simple hypertension. What happens in the kidney when you take this drug?
Distal tubule - HCTZ
Loop of Henle - furosemide
At which locations in the kidneys do diuretics act? Then name a typical drug that acts at that location.
Hydrochlorothiazide (HCTZ). Super cheap as well.
Drug of first choice for lowering elevated blood pressure is....
Diuretics excrete more water and therefore decrease the volume of blood in the body which in turn decreases peripheral resistance.
How do diuretics affect peripheral resistance?
Loop of Henle
Diuretics affecting the (distal tubule/Loop of Henle) are the most potent.
Loop of Henle. This is because they are the most powerful and so will result in a greater volume of water excreted from the body.
For serious medical conditions like CHF, we would use duiretics which affect the (distal tubule/Loop of Henle)
These drugs increase excretion of sodium and potassium, so they result in hypokalemia and hyponatremia. They also decrease blood volume.
List adverse events of diuretics like HCTZ and furosemide.
Spironolactone and triamterene
Name two potassium-sparing diuretics.
Non-specific aldosterone receptor antagonist
How does Spironolactone work?
Gynecomastia. This is because it binds to the sex hormone testosterone receptor and blocks it. This decreases testosterone production and thereby increasing peripheral conversion of testosterone to estradiol.

This displaces estradiol from sex hormone-binding globulin. The atleration in the ratio of free androgen to estrogen causes gynecomastia.
An adverse effect of spironolactone is... (why?)
HCTZ and Furosemide.
List 2 drugs which promote potassium excretion.
Changes in potassium metabolism are taken seriously because they often lead to neuromuscular, gastrointestinal and cardiac rhythm abnormalities. The most dangerous aspect of hypokalemia is the risk of ECG changes resulting in potentially lethal cardiac dysrhythmia.
Why do we care about potassium levels being high or low?
HCTZ + Lithium; lithium excretion is decreased so can lead to lithium toxicity

HCTZ + digoxin; digoxin toxicity may result

HCTZ + NSAIDs; NSAIDs reduce the antihypertensive effect of HCTZ
List the three important HCTZ interactions and what results.
Congestive heart failure.
What is digoxin used most often for?
Digoxin has a half-life of 2 to 3 days, so in the case of renal failure or decreased renal function, its elimination will be decreased, leading to higher blood levels of drug; higher blood levels may result in toxicity because digoxin is a narrow therapeutic index drug.
If you give digoxin to a patient with renal failure, what can you expect? (Hint: consider half-life)
Strengthens contraction of the ventricles (i.e., a positive inotropic action)
What is the pharmacological effect of digoxin?
HCTZ, beta blockers, calcium channel blockers, thyroid medicine, St. John's Wort supplement
Drug interactions - list the drugs which should NOT be given with digoxin.
Xanthopsia (altered color vision), specifically blue-yellow color blindness
Name an unusual adverse effect of digoxin
Cardiac arrhythmias, complete heart block, sinus bradycardia
Name some dangerous side effects of digoxin
Sodium channel blockers (disopyramide)
Beta blockers (propranolol)
Calcium channel blockers (verapamil; diltiazem)
Name some categories of antiarrhythmic drugs and list a drug example for each category.
Life-threatening arrhythmias such as A-fib, V-tach, V-fib
What 3 medical condition do antiarrhythmic drugs like amiodarone treat?
antiarrhythmic drug used to treat atrial fibrillation
Amiodarone is most well known for treating what?
NOT well. LOTS of interactions.
How well does Digoxin play with other drugs?
Nitrates can prevent angina attacks and relieve symptoms of angina. They work by relaxing blood vessels to the heart, thus increasing blood and oxygen supply. In other words, they reduce myocardial demand. Drugs used for prevention are beta blockers, calcium channel blockers, and even aspirin.
What drugs treat angina?
beta blockers, calcium channel blockers, ACE inhibitors, and ARBs are used to treat hypertension
What 4 categories of drugs are used to treat hypertension?
Ends in -olol: atenolol, metoprolol, propranolol
How do you recognize a beta blocker drug by its name?
Drug example: lisinopril

Affect the renin-angiotensin-aldosterone pathway involved in hypertension and BLOCK the formation of angiotensin I into angiotensin II.
ACE inhibitor drugs work how? Give drug example.
Beta blockers can be selective (beta-1 for the heart; atenolol) or NON-selective (beta-1 and -2; propranolol)
Beta blockers can be selective and nonselective. What does that mean? Give drug examples.
Prevent Formation: ACE Inhibitors
Block Receptor Action: ARBS and Angiotensin Receptor Blockers
Angiotensin II is a potent vasoconstrictor. Drugs can prevent its formation OR drugs can block its action at the receptor.

Tell me what category of drugs do this.
Bradycardia (remember in diabetics that propranolol can MASK the tachycardia that is a symptom of hypoglycemia)
List an important adverse effect of beta blockers
losartan and valsartan
Name two ARBS
Hyperkalemia; persistent dry cough; tickling sensation in throat
List adverse effects of ACE inhibitors
NSAIDs (!) which reduce the antihypertensive effect of these drugs
List a preventable drug interaction with antihypertensive drugs
DIET
The first way we control elevated lipids is via....
Lipids are NOT soluble in plasma and are transported in a protein capsule known as a "lipoprotein" of which there are multiple subtypes - chylomicrons, VLDL, LDL, HDL
How are lipids transported?
Treatment is via various drugs that have effects on LDL (cholesterol) and VLDL (triglycerides)
Elevated lipids are one of the risk factors for atherosclerosis (deposition of fats at walls of arteries, forming plaque).

Treatment is with drugs that have an effect on...
SECOND point of attack is use of bile sequestering agents which reduce blood levels of LDL. Bile sequestering drugs are ion-exchange resins that can bind bile acids in the gut lumen and remove them from enterohepatic circulation (example: cholestyramine)
The second way we control elevated lipids is via... (Give Example)
fenofibrate and gemfibrozil.
Fibric acid derivatives are drugs that also attack high lipid levels (VLDL and LDL) and increase HDL levels. Name two fibric acid derivative drugs .
These drugs are ion exchange resins so will bind with ANY acidic drug and remove it, too. Also, will remove lipid-soluble vitamins (A-D-E-K) from gut lumen.
List an interaction with bile sequestering drugs
Injected (B)
Heparin is administered...

a. Orally
b. Injected
c. Sublingual
d. As an Inhaler
Do not take with statin drugs (or else increase risk of rhabdomyolysis)
Name a serious drug interaction with fibric acid derivatives.
Statin drugs reduce LDL cholesterol and total blood cholesterol levels. They are very effective for all types of hyperlipidemias, too. They are even used to prevent myocardial infarction or stroke in patients with high cholesterol levels.
What are statin drugs used to treat?
PDE5 inhibitors like sildenafil (Viagra®); anticholinergics like atropine; beta blockers; calcium channel blockers; digoxin
Name important drug interactions for nitrates (nitroglycerin).
Inhibits the first enzymatic step in cholesterol synthesis
What does Atorvastatin do? How does it work?
Niacin
Which drug is cheap and effective BUT must take it in high doses which cause facial flushing (vasodilation), and hypotension?
Ezetimibe inhibits absorption from small intestine and thus decreases how much cholesterol gets dropped into the liver for storage; therefore, clearance of cholesterol is increased
Which drug inhibits the ABSORPTION of cholesterol in the small intestine?
It gets tricky because statins cannot be taken with fibric acid derivatives, niacin (nicotinic acid) cannot be taken with statins or bile sequestering drugs, cholesterol absorption inhibitors cannot be taken with bile sequestering drugs, fibric acid derivatives. The one combination that IS OKAY is a statin drug with a cholesterol absorption inhibitor (e.g., simvastatin and ezetimibe).
Can you add drugs to a drug regimen to lower cholesterol?
Rhabdomyolysis is the breakdown of muscle tissue that leads to the release of muscle fiber contents into the blood, and a protein called myoglobin is released into the bloodstream. It is then filtered out of the body by the kidneys. Myoglobin breaks down into substances that can damage kidney cells.
While rhabdomyolysis can occur from injury or anything that damages skeletal muscle, it can ALSO be caused by a drug - statin drugs. Describe rhabdomyolysis.
Prothrombin is converted into thrombin, which is a catalyst for the conversion of fibrinogen into FIBRIN
Run me through a simple version of the blood clotting cascade.
Enoxaparin.
Low Molecular weight Heparin goes by the drug name ____________
No.
Can Heparin dissolve a clot that is already formed?
Porcine gut where it is stored in mast cells.
Heparin comes from where?
Yes. Heparin CAN be given to pregnant women because it is a large protein molecule that cannot pass through the placenta easily; it has acidic groups on it that make it water soluble (COO- and SO3-)
Can heparin be given to pregnant women?
Heparin binds reversibly to antithrombin III (ATIII) and greatly accelerates the rate at which ATIII inactivates coagulation enzymes thrombin (factor IIa) and factor Xa. Therefore, it inhibits embolus and thrombus formation (i.e., prevents thromboembolism) - but CANNOT dissolve a clot that is already formed!
How does Heparin work?
Heparin INCREASES the clotting time but DECREASES the platelet count. Therefore, a patient on heparin is monitored for Prothrombin Time (PTT) and for their platelet count.
What are Heparin's effects on clotting time and platelet count?
hematuria, bruising, epistaxis, ecchymosis, hypotension and blood in stool.
A patient on heparin and Warfarin must be monitored for bleeding which is the #1 adverse event. Some signs of bleeding are:
Hemorrhage
What is the life-threatening adverse effect of heparin?
Warfarin (Coumadin®) inhibits the ability of the liver to synthesize vitamin-K-dependent clotting factors.
How does Warfarin work?
Determined individually for each patient. Treatment is monitored by measuring the INR.
What is the dose for Warfarin?
Protamine Sulfate; its positive charge interacts with the negative charge of heparin to form a stable but inactive complex.
What is the antidote for heparin?
Warfarin
primary ORAL anticoagulant used today is what?
Foods high in Vitamin K. Leafy green vegetables, salads, spinach.
What foods can mess with Warfarin?
Aspirin and NSAIDS
What two common pain relieving drugs should NOT be taken with Warfarin?
Vitamin K (Phytonadione)

It takes 24 hours. So, slow acting.
What is the antidote for Warfarin? How long does it take?
Hemorrhage
What is the life-threatening adverse effect of warfarin?
Warfarin CANNOT be given to pregnant women because it will cross the placenta and be shared with the developing fetus. ALSO- warfarin is teratogenic and can cause abortion.
Can Warfarin be given to pregnant women?
Bleeding, bruising, hematoma
List adverse effects of anticoagulant drugs
Antiplatelet drugs inhibit formation of thromboxane A2; why is this important? Thromboxane A2 triggers reactions that lead to platelet activation and aggregation. In other words, antiplatelet drugs decrease the responsiveness of the platelets to stimuli that would cause normally cause them to stick and combine together on the vessel wall. Thus, they inhibit the aggregation of platelets in the clotting process. Therefore - bleeding time is increased.
How do Anti-platelet drugs work?
aspirin and clopidogrel.
List two drugs as oral anti-platelet drugs.
Within 3 hours of the event that caused symptoms (3 hours for some drugs, 6 hours for newer drugs in this class).
A clot-buster drug is MOST effective when administered within.....
Prevent stroke; reduce tendency for transient ischemic attack; prevent thrombus formation (e.g., in patients with a graft or stent to maintain its patency). Antiplatelet therapy is a first-line medical treatment for patients with acute coronary syndrome.
Why take an antiplatelet drug?
Other anticoagulants (!) such as heparin, warfarin, NSAIDs.
Patients who are being treated with warfarin may sometimes be prescribed antiplatelet drugs, such as aspirin. As warfarin and antiplatelet drugs increase the risk of bleeding, their combination can put patients at risk of a major hemorrhage. This risk may be further increased by the patient's age and other illnesses.
What drugs should you NOT take with antiplatelet drugs?
streptokinase and urokinase
List two drugs which dissolve a clot that is already formed?
A thrombolytic drug breaks down a thrombus that is already formed - a clot-buster drug. It is an enzyme that activates the natural anticlotting fibrinolytic mechanism to convert plasminogen into plasmin which destroys and breaks down the fibrin threads in the blood clot. The result is fibrinolysis or clot disintegration.
How can we break a clot which has already formed?
Inhibit a fibrin clot from forming
If you INHIBIT THROMBIN, what are you preventing from happening?
Yes, aminocaproic acid which stabilizes fibrin to stabilize a clot.
Is there an antidote for a thrombolytic drug?
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