21. Chap 14.5, 14.6, 14.7 Clotting and antilipids

What can occur if a pt has inadequate blood clotting? Too much blood clotting?

Not enough: Hemorrhage

Too much: Thrombogenesis (formation of a clot)

Describe how extrinsic and intrinsic clotting factors affect a blood clot

Both extrinsic and intrinsic clotting factors call on thrombin and fibrin to form a clot

How does tissue plasminogen activator (tPA) work?

Helps break down blood clots

What are some types of drugs for overactive clotting? (3)

Anticoagulants

Antithrombotics

Thrombolytics

When are anticoagulants typically used? What are the primary types? (2)

Used in venous thrombosis

Heparin and oral anticoagulants

How does heparin work? How quickly does it work? How is it administered?

Increases effects of antithrombin III

Rapid effects, administered parenterally (injection)

What is unfractionated heparin? Describe it's use

Heparin that's delivered via heparin, several injections per day, unpredictable effects

What is low molecular weight heparin (LMWH)? Describe it's use

Heparin that's delivered sub-Q once a day, more predictable, safer response than unfractionated

What is heparin-induced thrombocytopenia (HIT)? Type I vs type II?

Decreased platelet count because of heparin use

Type I: Asymptomatic

Type II: Can be life threatening. Look for limb going cold or numb

How do oral anticoagulants, like Warfarin (Coumadin) work?

Inhibit vitamin K function in the liver, decreased synthesis of certain clotting factors

Can pts on Warfarin eat food sources of vitamin K?

Yes, can eat some but should not go out of their way to supplement vitamin K

How long of a time lag is there typically for oral anticoagulants to work?

Time lag of 3-4 days, used after heparin

What are other types of anticoagulant drugs? (2)

Direct thrombin inhibitors

Factor Xa inhibitors

How is aspirin used as an anticoagulant?

Used as an antiplatelet drug, prevents arterial clots in MI and stroke, prevents DVT

What are antithrombotic drugs?

Drugs that inhibit platelet activity and decrease platelet induced clots

How does aspirin have an anticlotting effect?

Inhibits prostaglandins and thromboxanes genesis, decreases platelet activity and aggregation

What is the difference between the uses of aspirin as an anticlotting factor for men and women?

Better at preventing MI in men

Better against stroke in women

What is a therapeutic dose for aspirin?

81 mg/day

"Baby aspirin"

What are some other antiplatelet drugs? (2)

ADP inhibitors

Glycoprotein IIb-IIIa inhibitors

What are thrombolytic drugs?

Drugs that initiate clot breakdown by activating plasmin (fibrinolysin)

How do thrombolytic drugs affect MI or stroke?

Can dissolve clots, restoring blood flow in MI or stroke

What are some typical thrombolytic agents? (4)

tPA

Urokinase

Reteplase

Tenecteplase

Is one thrombolytic superior for MI? How soon must they be used for best effects?

No agent superior for MI

Decreases mortality by 50% if given within 1 hour

What is the preferred type of thrombolytic for stroke? How soon must it be used?

tPA preferred

Administered within 2 hours of symptom onset

What is the primary risk to keep in mind when working with pts on anticlotting drugs?

Take care during dressing changes, debridement and manual to decrease risk of hemorrhage

How can hemophilia be treated? (3 ways)

Clotting factor replacement

Fibrinolysis inhibitors

Vitamin K supplements

How do statins help reduce hyperlipidemia?

Inhibit HMG-CoA reductase enzyme, decreasing cholesterol biosynthesis and increasing hepatic LDL breakdown

What are the main effects of statins on blood lipids? (2)

Decrease LDL and VDLs, triglycerides

Increase HDL

What are the additional beneficial effects of statins on blood lipids? (5)

Enhance vasodilation

Anti-inflammatory

Anti-oxidant

Neuroprotection for PD, AD

Anticancer

What is statin-induced myopathy? What % of pts get it?

Muscle breakdown caused by statin use

10% of pts get it

What are some of the predisposing factors for statin myopathy? (2 types)

Fixed factors

Modifiable factors

How do fibric acids affect blood lipids?

Activate nuclear receptors that affect genes controlling lipid metabolism

What is the primary effect of fibric acids on blood lipids? (2)

Decreases triglycerides

Increases VLDL breakdown

What are other antilipid agents? (2)

Niacin

Bile acid binding drugs

What are some of the adverse affects of antilipid agents? (3)

GI problems

Liver toxicity

Myopathy