Lecture Course 3: Cardio And Renal Flashcards
Flecainide
Na channel blocker.
Class IC antidysrythmic.
No effect on AP but very slow association and dissociation.
Spermine
Intracellular polyamide which acts as a valve in inward rectifying potassium channels.
Amiodarone
Prolongs the cardiac AP and thus also the refractory period
Can block both inward Na and outward K - complex mechanism
Used for ventricular dysrhythmia
Digoxin
Cardiac glycoside Inhibit NaKATPase [Ca]i ≈ Na³ Calcium extrusion reduced Used in treatment of congestive heart failure.
Digitoxin
Cardiac glycoside Inhibit NaKATPase Cai ≈ Na³ Calcium extrusion reduced Used in treatment of congestive heart failure.
Ouabain
Cardiac glycoside Inhibit NaKATPase Cai ≈ Na³ Calcium extrusion reduced Too potent for use in treatment of congestive heart failure.
Dobutamine
B1 agonist. Sympathomimetic agent.
Used in congestive heart failure, esp in shock. Intravenous.
Positive ionotropic effect but may also increase rate, and increases O2 demand
May cause dysrhythmia, potentiate hypertension, etc
Bisoprolol
B1 antagonist
Used to treat heart failure
Carvedilol
B1 blocker
Used to treat heart failure
Milrinone
PDE type III inhibitor (potentiates cGMP)
Inodilator. May produce dysrhythmia.
Prevents cGMP breakdown which causes similar effects to b blockers
Vasodilation in smooth muscle
Dipyridamole
PDE V inhibitor.
Raises intracellular cAMP
Used in treatment of heart failure
Also blocks transport of adenosine into cell, thus prolonging neurotransmitter action
Caffeine
Methyxanthine. Non selective PDE inhibitor Increases intracellular calcium A1 and A2 antagonists -> positive ionotropic and chronotrophic effects May lead to dysrhythmia
Theophylline
Methyxanthine. Non selective PDE inhibitors A1 and A2 antagonists -> positive ionotropic and chronotrophic effects May lead to dysrhythmia
Pimobendan
Inodilator - inhibits PDE III
‘calcium sensitiser’ - increases cardiac calcium binding efficiency without requiring greater energy
Used in treatment of canine dilated cardiomyopathy and mitral valve regurgitation, especially Dobermen!
Levosimendan
Inodilator - inhibits PDE III
‘calcium sensitiser’ - increases cardiac calcium binding efficiency without requiring greater energy
Used in human medicine in other countries
Streptokinase
Anti clot drug
Binds plasminogen activator to activate Plasmin
Plasmin inhibits factor 7, 5 and Thrombin
Plasmin
Serine protease, activated by anti clot drugs
Hydrolyses Arg-Lys bonds
Targets 7a, 5a, thrombin
Anistreplase
Combination of plasminogen and anisoylated streptokinase
Streptokinase activates Plasmin
Anisoyl group removed in blood - prolonged activity
Anti clot drug
Alteplase & duteplase
Recombinant human tissue plasminogen activator
Greater activity on plasminogen bound to fibrin clot -> localises action
Activates Plasmin - targets 7a, 5a, thrombin
Anti clot drug
Alteplase = single chain
Duteplase= double chain
Aspirin
Prevents platelet aggregation/bridging by inhibiting ADP binding to platelets
Often used in this respect alongside Clopidogrel
Clopidogrel
Inhibits platelet aggregation by inhibiting ADP binding to platelet receptor
Used in combination with aspirin
Eptitibatide
Anti clot drug
Cyclic heptapeptide inhibitor
Inhibits glycoprotein IIb/IIIa which causes platelet aggregation in conjunction with fibrinogen
Tirofiban
Anti clot drug
Non peptide inhibitor
Inhibits glycoprotein IIb/IIIa which causes platelet aggregation in conjunction with fibrinogen
Prevention of myocardial infarction in older patients
Abciximab
Monoclonal antibody against vitronectin receptor on platelets, endothelial and vascular smooth muscle
Vitronectin involved in cell adhesion and haemostatis
Used with coronary angioplasty for coronary artery thrombosis
Heparin
Endogenous/injectable Anticoagulant, produced by basophils and mast cells
Binds antithrombin IIIA (ATII) to expose its active site
Activated enzyme inactivates thrombin and Xa
Treatment for DVT, myocardial infarction, unstable angina and as a prophylactic drug to prevent clots forming during surgery
Warfarin
Oral anticoagulant
Inhibits synthesis of thrombin, VII, IX, X and regulatory protein factors C, S, Z via enzyme ATII
Also used to prevent clot formation on prosthetic heart valves
Interacts with food and drink chemicals :/
Dabigatran
New anticoagulant
Thrombin inhibitor via ATII a
Atrial fibrillation drug/short term prophylactic to prevent clotting in hip/knee replacement surgery
River ouabain
Factor Xa inhibitor
Used in atrial fibrillation/temporary prophylactic
Aminocaproic acid or tranexamic acid
Prevents severe bleeding during excessive clot lysis
Inhibits plasminogen activation
Acetazolamide
Diuretic
Carbonic anhydrase inhibitor
- decrease NaHCO3- re absorption
- > nateuresis
Mostly obsolete as a diuretic, used to lower intraocular pressure in glaucoma
Mannitol
Osmotic diuretic
Small molecule that is filtered via the glomerular apparatus
No reabsorption but retains osmotic pressure
-> less H₂O efflux
-> less Na efflux
Maintains urine flow.
Used acutely to treat cerebral oedema
Furosemide and Bumetanide
Loop diuretics
Fast acting: within an hour orally, within 10 minutes IV
Venodilatory action precedes diuretic
Blocks NaKCC in thick aLoH
Powerful - 15-25% filtrate excretion
Problems :
Hypokalaemia and metabolic alkalosis
Calcium and magnesium loss
Uric acid excretion reduced ~> gout
hydrocholorothiazide and bendroflumethazide
Thiazide diuretic
Act in DCT by inhibiting NaCl cotransporter
Problems:
- hypokalaemia (do NOT combine with cardiac glycosides) and metabolic alkalosis
- Uric acid excretion down (gout)
- increases Mg excretion, decrease calcium excretion
amiloride and triamterene
Potassium sparing diuretic
Block apical sodium channels in late DCT, a major side of potassium loss
Often combined with loop or thiazide diuretics
