Pharmacological Management

Diuretics

Diuretics are indicated for symptomatic relief in patients with pulmonary and systemic venous congestion due to heart failure (HF) following myocardial infarction (MI). Loop diuretics such as furosemide are generally required when symptoms are moderate or severe; when oedema persists, a thiazide diuretic can be added.¹

Diuretics trigger activation of the renin-angiotensin-aldosterone system (RAAS) in patients with mild HF, and should usually be used in combination with an ACE inhibitor or angiotensin II receptor blocker (ARB).¹

Because of their potential to cause electrolyte disturbances, particularly hypokalaemia and hyponatraemia, diuretics should be used with care in the post?MI setting. Potassium, sodium and creatinine levels should be monitored during therapy.¹

Drugs that inhibit the RAAS (i.e. ACE inhibitors, ARBs and aldosterone receptor antagonists) tend to increase potassium levels, opposing the hypokalaemic effect of diuretics. Therefore, in patients receiving both a diuretic and a RAAS inhibitor, potassium supplementation is not usually required. Indeed, such supplementation could increase the risk of hyperkalaemia in these patients, as could the use of a potassium-sparing diuretic. In general, potassium-sparing diuretics should be avoided in patients receiving a RAAS inhibitor.¹