Preload Reduction - Diuretics And Venodilators

Question 1

Frusemide

Answer 1

Brand name: Frusecare, Frudix

Use: Management of CHF and non-cardiogenic oedema

Pharmacology: Loop diuretic, inhibits Na/K/Cl cotransporter in thick ascending limb of the loop of henle. Loss of Na, K, Cl and water in the urine

Contraindications: dehydration and anuria

Adverse effects: hypoK, hypoCa, hypoCl, hypoNa,dehydration, PU/PD, ototoxicity in cats, Gi effects

Question 2

Spironolactone

Answer 2

Drug name: Aldactone

Use: Use in treatment of CHF, useful in hypokalaemic patients
Pharmacology: Aldosterone receptor antagonist, acts in the distal tubule. Acts on myocardium and cardiac vasculature to reduce aldosterone-mediated remodelling

Contraindications: hypoA, hypoNa, hyperK, NSAID use, pregnancy, lactation

Adverse effects: hypoNa and hyperK, prostatic atrophy

Question 3

Hydrochlorothiazide

Answer 3

Drug name: Moduret

Use: Additional therapy for CHF when clinical signs become refractory to frusemide. Also have hypertensive effects. May prevent reoccurrence of Ca Oxalate crystals

Pharmacology: Inhibit reabsorption of Na and Cl in the distal convoluted tubule, resulting in Na, Cl and water loss on the urine

Contraindications: renal impairment (reduces GFR)

Adverse effects: hypoNa, hypoK

Question 4

Venodilators - Nitroglycerin

Answer 4

Drug name: Nitrocine

Use: short term management of cardiogenic oedema (1-2 days) in CHF

Pharmacology: systemic vasodilator, causes reduction in venous return as a consequence of venodilation. Efficacy is debatable

Contraindications: hypotension, hypovolaemia, cerebral haemorrhage, head trauma

Adverse effects: hypotension, tachycardia and a rash at administration site