Related Subjects: |Hypertension |Acute Heart Failure |Chronic Heart Failure Loop Diuretics | Entresto Sacubitril with Valsartan | Ivabradine | Furosemide | Angiotensin Converting Enzyme Inhibitors | Cardiac Resynchronisation Therapy (CRT) Pacemaker |
Its diuretic effect is dose dependent. In cases of chronic renal failure, very high doses may be required. Diuretics should not be used on a long-term basis to treat simple gravitational oedema. This will usually respond to increased ambulation, raising the legs and support stockings.
About : Always check the BNF link here
- Loop diuretics: 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.
Chemistry
- It is an anthranilic acid derivative : 4-chloro-N-furfuryl-5-sulfamoylanthranilic acid
Mode of action
- 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/Dose
- Fluid overload (CCF/LVF. Central oedema):Furosemide (US Lasix) 20 mg OD to 80 mg BD.
- Mild Peripheral Oedema: Furosemide (US Lasix) 20-40 mg OD but may settle with leg elevation and low doses on alternate days. Watch for orthostatic hypotension. Combine with increased ambulation, raising the legs and support stockings.
- Acute LVF:Furosemide (US Lasix) 50-100 mg given as a single iv dose or an infusion over several hours
- Hypertension: Often given with An ACEI or ARB:Furosemide (US Lasix) 20-40 mg OD
Dose range:You must check with BNF or drug datasheet
| Name | Starting Acute IV Dose | Frequency | Route |
|---|---|---|---|
| Furosemide | 40-100 mg | stat | IV for Acute Pulmonary Oedema |
| Furosemide | 150 mg (maximum 1.5g /day) | As needed Infusion | Infusion over 3 hours usually for decomensated heart failure |
| Name | Regular Oral dose | Frequency | Route |
| Furosemide | 20-80 mg | OD or BD 8am/1pm | PO |
Contraindications
- Avoid with ototoxic drugs
- Monitor renal function and electrolytes
- Hypokalaemia can increase Digoxin toxicity
Side effects
- Elderly patients are particularly susceptible to the side-effects of diuretics.
- Volume depletion and orthostatic hypotension and falls especially in elderly
- Low K, Low Mg, Low Ca Raised Ca in urine, Raised uric acid (gout), Raised Glucose
- Low BP, gynecomastia, urinary retention, AKI
- Ototoxicity - tinnitus especially avoid with aminoglycosides
Interactions
- Digoxin toxicity as causes hypokalaemia
- Can cause lithium toxicity through its actions on renal clearance