Cardiovascular 2 Flashcards
What are the non selective a-agonists?
Epinephrine
Norepinephrine
What are the selective a1 agonists?
Dopamine (high dose)
Phenylephrine
What are non-selective a antagonists?
Phenoxybenzamine
Phentolamine
What are selective a1-antagonists?
Prazosin
What are direct and indirect acting sympathomimetics?
Vasopressin
Ephedrine
Pseudoephedrine
Phenylpropanolamine (PPA)
What drugs are ACE inhibitors?
Enalapril
Benazepril
What is the MOA of enalapril and benazepril?
ACE inhibitors
Inhibit angiotensin II synthesis and aldosterone
Increase bradykinin (ACE usually inactivates)
- vasodilator
- stimulate PG
What is the osent on ACE inhibitors?
Usually slow with peak effects seen 1-2wks after starting treatment
Where are enalapril and benazepril metabolized and excreted
Both metabolized in the liver
Enalapril -renal clearance
Benazepril - hepatic > renal clearance
What are the indications for ACE inhibitors ?
Congestive heart failure
Hypertension
Protein losing renal disease -> reduce intraglomerular hypertension
What are the precautions to using ACE inhibitors ?
GI signs
Hypotension
Risk of worsening azotemia (high nitrogen) due to decrease GFR
What drug is a phosphdiesterase inhibitor?
Sildenafil
What is the MOA of sildenafil?
Phosphodiesterase V inhibitor -> increased cGMP -> nitric oxide (NO) mediated vasodilation
Smooth muscle of pulmonary vasculature
What are the therapeutic indications of sildenafil?
Treatment of pulmonary hypertension
Eisenmenger’s syndrome
Erectile dysfunction in humans
What are precautions to using sildenafil?
Systemic hypotension
Caution in hypovolemic patients, left ventricular outflow tract
GI signs
When is sildenafil contraindicated ??
Concurrent use with nitrates
What are the direct acting vasodilator?
Nitroprusside
Nitroglycerine
Hydralazine
What is the MOA of mictroprusside and nitroglycerine?
Increased formation of NO -> activate guanylyl cyclase -> increase cGMP -> stimulation of GMP-dependent protein kinase -> arteriolar and venous vasodilation
Relax vascular smooth muscle
What is the MOA of hydralazine?
Increase local PGI2 concentration -> alter cellular calcium metabolism in smooth muscle
- interferes with calcium movements
- prevent initiation and maintenance of contractile state
What are the indications to using hydralazine?
Hypertensive crisis Afterload reduction (severe CHF)
What are precautions to using hydralazine?
Hypotension -> may be severe
Syndrome
Weakness, lethargy
When is hydralazine contraindicated??
Renal disease
Reduce renal blood flow -> activate RAAS -> worsen renal injury
Pre-treat with ACE-I or spironolactone to reduce risk
What is the MOA of Amlodipine?
Calcium channel blocker
Inhibit the influx of extracellular calcium across myocardial and smooth muscle cell membranes
- > decrease contractions
- > dilation of the coronary and systemic arteries
What are the clinical effects of amlodipine?
Neg inotropic effect Neg chronotropic effect Increase oxygen delivery to myocardial tissue Decrease afterload Coronary vasodilation
What effects does amlodipine have on the vasculature?
Decrease peripheral resistance
Decrease systemic BP
What is the drug of choice for first line treatment of hypertension in CATS :)
Amlodipine
What are precautions to using amlodipine?
Hypotension Bradycardia AV block GI signs Elevated liver enzymes
What drug is an angiotensin II antagonist?
Losartan
What is the MOA of losartan? What is its indication?
Angiotensin II receptor competitive antagonist
Antihypertensive (adjunct therapy)
What is the mechanism of action of sildenafil?
PDE V inhibitor
What is the main indication of sildenafil?
Treat pulmonary hypertension
What drugs are used to treat pulmonary hypertension?
Sildenafil (drug of choice)
Pimobendan (can delay the onset, but not the treatment of choice)
What is the main clinical indication of amlodipine?
Treats systemic hypertension
What is a more balanced venodilator, hydralazine or nitroprusside??
Nitroprusside
What is a hemostatic agent?
Helps support blood clotting
What is an anticoagulant?
Inhibit coagulation factors
What is an antithrobotic?
Inhibits platelets
What is a thrombolytic?
Break down an existing clot
What is the MOA of phytonadione
Vitamin K1
Necessary for the synthesis of coagulation factors II, VII, IX, X
What are the vitamin K-dependent coagulation factors??
II, VII, IX, X
What is the drug of choice for treatment of bleeding disorders associated with vitamin K1 deficiency
Phytonadione
What is the antidote for anticoagulant rodenticide toxicity or hemorrhage associated with warfarin ?
Phytonadione
How do you administer phytonadione?
ONLY give SQ -> risk of anaphylaxis if given IV
What are the hemostatic agents ?
Phytonadione - vit K1
Protamine sulfate
Aminocaproic acid (antifibrinolytic)
Desmopressin acetate (hormonal agent)
What is the MOA of protamine sulfate?
Complexes with heparin to form and inactive stable salt
What is the drug of choice for treatment of hemorrhage secondary to heparin over dosage?
Protamine sulfate
What are precautions to using protamine sulfate ?
Rapid IV injection
Hypotension Bradycardia Pulmonary hypertension Dyspnea Possible hypersensitivity reaction
What is the MOA of aminocaproic acid?
Inhibits fibrinolysis via inhibitory effects on plasminogen activation substances and some antiplasmin action
(Inhibit clot breakdown)
What is used to treat conditions associated with increased bleeding due to hyperfibrinolysis?
Aminocaproic acid (antifibrinolytic)
Aminocaproic acid has been used prophylactiaclly to prevent post-op bleeding in _____________
Greyhounds
What is the MOA of desmopressin acetate?
Causes dose-dependent in plasma factor VIII and plasminogen factor
Support primary hemostatis -> platelet function
What is the drug of choice for treatment of bleeding due to vonWillebrand’s disease
Desmopressin
Also for central Diabetes insipidus
What drug has been used to treat blooding due to aspirin toxicity in dogs
Desmopressin
What is a precaution to desmopressin use?
Fluid and sodium retention with overdose
What are the anticoagulants ?
Unfractionated heparin
Low molecular weight heparin (dalteparin and enoxaparin)
Warfarin sodium f
What is the MOA of unfractionated heparin?
Binds to antithrombin III to inactivate coagulation factor Xa and prevents the conversion of prothrombin to thrombin
What are the indications to use unfractionated heparin?
Heparinized saline flush
Treat certain thromboembolic disease
Prophylactic treatment in patients at risk of developing thromboembolic disease
DIC (controversial)
What are precautions to using unfractionated heparin ?
Risk of bleeding
Heparin-induced thrombocytopenia
MONITORING -> coagulation time
Administered IV or SQ
What are the low molecular weigh heparin ?
Dalteparin
Enoxaparin
What is the MOA of low molecular weight heparin?
Bind antithrombin III to inactivate coagulation factor Xa
Preferentially inhibit factor Xa and have minimal impact on thrombin and clotting time
What are the therapeutic indications to low molecular weight heparin?
Prophylactic to treatment of pulmonary embolism or thromboembolic disease
Deep vein thrombosis
What are precautions of low molecular weight heparin
Hemorrhage unlikely, but possible
Must be given SQ
Frequent dosing
Expensive
What is the MOA of warfarin sodium?
Inhibit vitamin K epoxied reductase
-> interfere with synthesis of coagulation factors II, VII, IX, and X
What are the therapeutic indications of warfarin
Primarily used in dogs for the oral, long-term treatment of thromboembolic disease
What are the precautions of warfarin?
Life threatening hemorrhage possible -> dose related
CAREFUL monitoring of clotting times
Highly protein bound -> drug drug interactions significant
What are the antithrombotics?
Aspirin (NSAID)
Clopidogrel bisulfate (platelet aggregation inhibitor)
What is the MOA of Asprin
Reduce platelet aggregation through inhibiting synthesis of thromboxane A2
Selective COX1 inhibition. -> anti-inflammatory
What is the therapeutic indication of asprin ?
Prophylaxis or treatment of thrombotic disease
- feline aortic thromboembolism
- immune mediated hemolytic anemia
Asprin is contraindicated in what cases
GI ulceration and active GI bleeding
What are precautions of asprin use?
VERY long half life in cat -> EOD dose (72hrs)
High dose can cause increased platelet aggregation
Clopidogrel bisulfate MOA?
Reduce platelet aggregation through selectively inhibiting the ADP receptor on the platelet surface
What is the therapeutic indications of clopidogrel bisulfate
Prophylaxis or treatment of thrombotic disease
When is clopidogrel bilsulfate used contraindicated?
GI ulceration and active GI bleeding
What is a precaution to using patent aggregation inhibitor ?
AKA clopidogrel
Low risk of clinically significant bleeding when used alone
What are the thrombolytic drugs?
Streptokinase
Urokinase
Tissue plasminogen activator (t-PA)
What thrombolytic drug is fibrin clot specific?
Tissue plasminogen activator
What is the MOA of thrombolytic?
Activate plasminogen to breakdown existing clots-> thrombolysis
What is the therapeutic indication to using thrombolytic?
Treatment of existing thrombus or thromboembolism
What are precautions to thrombolytic use?
Life threatening hemorrhage possible
Must be given IV
Which of the following dugs acts by inhibiting fibrinolysis ? Vitamin K1 Protamine sulfate Aminocaproic acid Clopidogrel
Aminocaproic acid
What is the specific antidote for anticoagulate rodenticide toxicity?
Vitamin K1
AKA phytonadione
What is the MOA of clopidogrel?
Anti-platelet aggregation through ADP inhibition
What is a fibrin clot specific thrombolytic?
Tissue plasminogen activator
