Loop diuretics

Related Subjects: Chronic Heart Failure | Heart Failure and Pulmonary Oedema | Loop Diuretics | Entresto Sacubitril with Valsartan | Ivabradine | Furosemide | Angiotensin Converting Enzyme Inhibitors | Cardiac Resynchronisation Therapy (CRT) Pacemaker |

About: Always check the BNF or equivalent for prescribing advice

• See BNF or equivalent for UpToDate prescribing advice
• These are potent diuretics useful for the rapid excretion of Salt, other electrolytes and water. Often used in the acute treatment of Left ventricular failure.

Mode of action

• They block primarily the absorption of sodium and chloride not only in the proximal and distal tubules but also in the loop of Henle. Heavily bound to albumin.
• Effect depends on renal clearance so may be diminished in older patients

Indications

• Acute LVF, Congestive cardiac failure
• Hypertension - not recommended as a single agent
• Fluid overload - Liver failure. Nephrotic syndrome
• Treat hypercalcaemia, Treat hyperkalaemia

Contraindications

• Avoid with ototoxic drugs
• Monitor renal function and electrolytes
• Hypokalaemia can increase Digoxin toxicity

Dose

• The usual initial dose of furosemide is 20 to 80 mg given as a single oral dose
• The usual initial dose of Bumetanide is 1 to 2 mg given as a single oral dose
• In the treatment of acute LVF doses such as furosemide 40 to 80 mg given as a single iv dose

Side effects

• Volume depletion and orthostatic hypotension and falls especially in elderly
• Hypokalaemia and metabolic alkalosis
• Hypomagnesaemia
• Hypocalcaemia and Hypercalciuria and calcium excretion
• Hyperuricaemia (can lead to gout)
• Ototoxicity - tinnitus especially avoid with aminoglycosides
• Diabetes and Hyperglycaemia

Interactions

• Digoxin toxicity as causes hypokalaemia
• Can cause lithium toxicity through its actions on renal clearance