Pharma W5 Part 2

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Questions and Answers

What role does the enzyme CYP2C19 play in the effectiveness of Plavix?

It converts Plavix into its active form. (correct)

It prevents the metabolism of Plavix.

It binds Plavix to apolipoproteins.

It enhances the absorption of Plavix.

Which drug is a tissue plasminogen activator (tPA) used in thrombolytic therapy?

Simvastatin

Desmopressin acetate

Aprotinin

Alteplase (correct)

What is the primary function of antifibrinolytics in clinical practice?

To prevent the lysis of fibrin. (correct)

To increase the production of cholesterol.

To reduce triglyceride levels in blood.

To dissolve blood clots.

Which two medications are commonly advised against when using statins due to potential interactions?

Oral anticoagulants and grapefruit. Signup and view all the answers

What is the main adverse effect associated with HMG-CoA reductase inhibitors (statins)?

Muscle pain and myopathy. Signup and view all the answers

What condition may result from the breakdown of muscle protein in patients taking statins?

Kidney failure. Signup and view all the answers

Which of the following is a common treatment for excessive bleeding due to surgical complications?

Aprotinin. Signup and view all the answers

How much do statins typically reduce LDL cholesterol levels?

30-40% Signup and view all the answers

What is the primary role of anticoagulants in the management of blood clotting?

To prevent blood clot development. Signup and view all the answers

Which drug is associated with teratogenic effects?

Warfarin Signup and view all the answers

What is a common monitoring requirement for patients on Warfarin?

PT/INR Signup and view all the answers

Which of the following is NOT a characteristic of LMWHs (low molecular weight heparin)?

They require regular aPTT monitoring. Signup and view all the answers

What is the main action of antiplatelet drugs?

Prevent platelet adhesion at the injury site. Signup and view all the answers

Which statement about heparin is incorrect?

Heparin can be administered orally. Signup and view all the answers

Why is it important for patients taking Warfarin to maintain a consistent intake of vitamin K?

It ensures stable INR levels. Signup and view all the answers

What type of drug is Clopidogrel bisulfate?

Antiplatelet Signup and view all the answers

What is a major contraindication for the use of bile acid sequestrants?

Phenylketonuria Signup and view all the answers

Which of the following drugs is an example of a bile acid-binding resin?

Cholestyramine Signup and view all the answers

What side effect can bile acid sequestrants help alleviate?

Diarrhea Signup and view all the answers

Which vitamin levels might be reduced due to the high doses of bile acid sequestrants?

Fat-soluble vitamins A, D, E, and K Signup and view all the answers

What is a common side effect of Niacin when used in higher doses as an antilipemic?

Flushing Signup and view all the answers

Which mechanism of action is associated with fibrates?

Activation of lipoprotein lipase Signup and view all the answers

What risk is increased when fibrates are used in conjunction with statins?

Myositis and rhabdomyolysis Signup and view all the answers

Patients on long-term therapy with bile acid sequestrants may need which of the following?

Fat-soluble vitamin supplements Signup and view all the answers

Study Notes

Antiplatelet Agents

Plavix (clopidogrel) requires activation by enzyme CYP2C19; inhibitors of this enzyme diminish its effectiveness in preventing blood clots.

Thrombolytics

Thrombolytics dissolve thrombi to restore blood flow.
Tissue Plasminogen Activator (t-PA) converts plasminogen into plasmin for clot lysis.
Notable tPA therapies:
- Alteplase (Activase)
- Tenecteplase (TNKase)
Commonly used for acute ischemic stroke, acute myocardial infarction (MI), and massive pulmonary embolism (PE).
tPA has a short half-life (~5 minutes), providing rapid action.

Antifibrinolytics

Antifibrinolytics hinder the action of tPA to support clot formation, preventing excessive bleeding during surgeries.
Key antifibrinolytic agents:
- Tranexamic Acid (Cyklokapron)
- Desmopressin Acetate (DDAVP) — effective in hemophilia A and type I von Willebrand’s disease.
- Aprotinin (Artiss, Trasylol)

Antilipemics

Cholesterol and triglycerides necessitate apolipoproteins to form lipoproteins for transport in blood.
LDL is termed "bad cholesterol" and HDL is "good cholesterol."

Dyslipidemia Management

Initial management options include lifestyle changes, followed by pharmacologic interventions based on lipid profiles.
Statins (HMG-CoA reductase inhibitors) are first-line agents, reducing LDL by 30-40% and increasing HDL by 2-15%.
Common statins:
- Simvastatin (Zocor)
- Atorvastatin (Lipitor)
Statins function by inhibiting HMG-CoA reductase, though they may cause muscle-related adverse effects including rhabdomyolysis and myoglobinuria.

Other Dyslipidemic Medications

Bile Acid Sequestrants: Bind bile acids, preventing reabsorption — can treat diarrhea through resulting constipation.
- Cholestyramine (Olestyr)
Niacin (vitamin B3) is effective for lowering lipid levels but may cause flushing and GI issues; starting with low doses can mitigate side effects.

Fibric Acid Derivatives (Fibrates)

Fibric acid derivatives activate lipoprotein lipase, enhancing cholesterol breakdown and increasing HDL by 25%.
Examples include bezafibrate, gemfibrozil, and fenofibrate; use with caution due to potential liver and kidney complications.

Coagulation Modifiers

These drugs alter the coagulation cascade to either inhibit clot formation or promote clot lysis.

Anticoagulants

Effective immediately, they prevent new blood clots and inhibit existing clots from worsening.
Common anticoagulants include:
- Heparin Sodium: Requires monitoring of aPTT, with protamine sulfate as its antidote; useful for DVT.
- Low Molecular Weight Heparins (LMWH): Such as enoxaparin (Lovenox); focus primarily on factor Xa.
- Warfarin (Coumadin): Oral vitamin K antagonist; teratogenic with a delayed therapeutic effect requiring INR monitoring.

Xa Inhibitors

Provide prevention and treatment for DVT by inhibiting factor Xa.
Examples include apixaban (Eliquis).

Antiplatelet Medications

Aspirin and clopidogrel prevent platelet aggregation; both carry risks of bleeding.
Aspirin is chewable for rapid absorption and must be withheld prior to surgery to avoid prolonged effects on platelets.

Key Considerations

Patients on statins must avoid grapefruit due to drug interactions that increase muscle damage risks.
Maintain a consistent vitamin K intake while on warfarin to avoid fluctuations in anticoagulant effect.
Patients on long-term lipid-lowering therapy may require supplementation of fat-soluble vitamins (A, D, K).
Educate patients on the delayed onset of medication effectiveness and monitor for adverse effects, especially with liver enzymes.

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