Pharmacology 2 (exam 4) - NotebookLM

50 vocabulary flashcards covering antiarrhythmic drug classes, cardiac electrophysiology, fluid therapy, electrolytes, coagulation tests and modifiers, and thyroid/glucocorticoid/adrenocortical drugs as presented in the notes.

Arrhythmia

An abnormality in heart rate, regularity, origin of impulse, or impulse conduction.

MOA of arrhythmias

Abnormalities of impulse formation and/or conduction, often involving automaticity or re-entry mechanisms.

Class I Antiarrhythmics

Sodium channel blockers that slow conduction in myocardial membranes and stabilize membranes.

Sodium Channel Blockers

Drugs that block fast Na+ channels to slow conduction velocity in cardiac tissue.

Class IA

Subclass of Class I that depress conduction and prolong repolarization.

Quinidine

Class IA antiarrhythmic; prolongs action potential and refractory period; used for atrial fibrillation in horses.

Procainamide

Class IA agent; can be IV if lidocaine is insufficient; slows conduction and prolongs refractory periods.

Class IB

Subclass of Class I; shortens action potential and accelerates repolarization; effective in abnormal tissue.

Lidocaine

Class IB antiarrhythmic; inhibits inward Na+ current; IV use for ventricular arrhythmias; caution in cats.

Mexiletine

Oral Class IB Na+ channel blocker; similar to lidocaine; used for chronic ventricular arrhythmias.

Class II Antiarrhythmics

Beta-blockers that reduce sympathetic input and slow AV conduction.

Propranolol

Nonselective beta-blocker; DOC for atrial fibrillation/flutter in some cases; significant first-pass metabolism.

Metoprolol

Beta-1 selective blocker; used for feline tachycardia associated with hyperthyroidism.

Atenolol

Beta-1 selective blocker; used for atrial fibrillation/flutter and feline HCM.

Esmolol

Ultra-short-acting beta-blocker; IV use for acute SVT.

Class III Antiarrhythmics

Potassium channel blockers that prolong action potential duration and refactory period.

Amiodarone

Broad-spectrum Class III antiarrhythmic with properties of all classes; long half-life and lipophilic; hepatotoxicity and neutropenia risks.

Desethylamiodarone

Active metabolite of amiodarone that also blocks fast Na+ channels.

Sotalol

Nonselective beta-blocker with additional potassium channel blocking (Class II/III); effective for ventricular tachyarrhythmias.

Class IV Antiarrhythmics

Calcium channel blockers that slow AV node conduction; examples include diltiazem and verapamil.

Diltiazem

Class IV calcium channel blocker used for certain supraventricular arrhythmias.

Verapamil

Class IV calcium channel blocker used for SVTs; monitor for toxicity.

Digoxin

Vagogic cardiac glycoside; slows AV conduction; used for SVTs; narrow safety margin.

Isotonic solution

Crystalloid with osmolality ~300 mOsm/L; resembles ECF (e.g., NS, LRS).

Lactated Ringer's Solution (LRS)

Balanced isotonic crystalloid; alkalinizing properties; used for fluid therapy.

Normal saline (NS)

0.9% saline; acidifying crystalloid used for fluid resuscitation and volume expansion.

Hypotonic solution

Fluid with lower osmolality than plasma; can cause fluid shifts into cells.

Hypertonic solution

Fluid with higher osmolality than plasma; used to draw water into intravascular space in shock.

Total Body Water (TBW)

Approximately 60% of body weight; total body fluid.

Extracellular Fluid (ECF)

20–27% of body weight; includes plasma volume and interstitial fluid.

Intracellular Fluid (ICF)

33–40% of body weight; fluid inside cells.

Oncotic pressure

Plasma protein-driven pressure that retains fluid in vasculature.

Osmolarity

Osmoles of solute per liter of solution.

Osmolality

Osmoles of solute per kilogram of solvent.

Antidiuretic Hormone (ADH)/Vasopressin

Hormone regulating water reabsorption in kidneys via V2 receptors; concentrates urine.

V2 receptors

Renal tubule receptors that mediate antidiuresis via aquaporin-2 channels.

Desmopressin (DDAVP)

Long-acting synthetic ADH analogue; used for diabetes insipidus and certain bleeding disorders.

aPTT

Activated Partial Thromboplastin Time; screen/test for heparin therapy efficacy.

Prothrombin Time (PT)

Coagulation test used with INR to monitor warfarin therapy.

INR

International Normalized Ratio; standardizes PT for monitoring vitamin K antagonist therapy.

Protamine sulfate

Antidote to unfractionated heparin; reverses anticoagulation effects.

Vitamin K (Phytonadione)

Cofactor for synthesis of vitamin K–dependent clotting factors; antidote for warfarin-type rodenticide toxicity.

Heparin

Anticoagulant; UFH used to prevent/treat thrombosis; monitored by aPTT or anti-Xa.

Low Molecular Weight Heparins (LMWHs)

Dalteparin, Enoxaparin; similar indications to UFH with different PK and monitoring needs.

Warfarin (Coumarin derivatives)

Vitamin K antagonist; inhibits II, VII, IX, X; monitored by PT/INR; variable dosing.

Streptokinase

Fibrinolytic agent that activates plasmin to dissolve clots.

Dexamethasone suppression test

Low-dose dexamethasone test to diagnose Cushing’s disease by HPAA feedback, with cortisol measurements at 4–8 hours.

Trilostane (Vetoryl)

Adrenolytic drug; DOC for canine pituitary-dependent hyperadrenocorticism; inhibits steroid synthesis.

Pergolide (Prascend)

Ergoline dopamine agonist used for equine Cushing’s (PPID) management.

Methimazole (MMI)

Thioureyrene antithyroid drug (TPO inhibitor); first-line for feline hyperthyroidism; oral or transdermal forms.

Carbimazole

Prodrug of methimazole; used in cats outside North America with fewer GI side effects.

Radioactive iodine (131I) Therapy

Selective destruction of functioning thyroid tissue; definitive cure for toxic goiter in cats; requires radiation safety precautions.

Technetium-99m scintigraphy

TcO4- thyroid scan; rapid uptake and safer imaging compared to radioiodine.

Thyroid-stimulating hormone (TSH) stimulation test

Diagnostic test for hypothyroidism; measures T4 response after exogenous TSH.

TRH stimulation test

Diagnostic test for thyroid reserve; less preferred than TSH stimulation in dogs; used in some hyperthyroid cats.

Glucocorticoids (GCs)

Steroid hormones with anti-inflammatory and immunosuppressive actions; HPAA negative feedback.

Methylprednisolone

Long-acting glucocorticoid with strong anti-inflammatory activity.

Prednisone/Prednisolone

Common glucocorticoids; prednisone is a prodrug converted to prednisolone in liver.

Trilostane (Vetoryl)

Adrenolytic used for Cushing’s disease; reduces cortisol synthesis.

Aldosterone

Mineralocorticoid that promotes Na+ reabsorption and K+/H+ excretion in kidney.

Fludrocortisone (Florinef)

Mineralocorticoid used in some Addison’s disease regimens.

ACTH stimulation test

Diagnostic test for adrenal function; measures cortisol response after synthetic ACTH.

TRH

Tripeptide that stimulates TSH release from the pituitary.