These recommendations are based on guidelines published by the National Institute for Health and Clinical Excellence (NICE) [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010], on a guideline published by the the European Society of Cardiology [European Society of Cardiology, 2008], and CKS expert reviewers.

Loop diuretics

• Usually, diuretics rapidly improve symptoms (breathlessness) and exercise performance in people with heart failure by reducing fluid overload. Most people with heart failure are treated with loop diuretics rather than thiazides, because loop diuretics are more powerful at inducing diuresis and natriuresis [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010].
• It is common practice to initiate diuretics at low doses, and to increase the dose as required to control symptoms of fluid overload [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010].
• If a person is suspected to have heart failure and needs symptomatic treatment while waiting to see a specialist, CKS recommends use of a loop diuretic. However, CKS recommends that specialist advice be sought if doses higher than furosemide 40 mg (or equivalent) are thought to be necessary because:
• The diagnosis may not be correct (particularly if the person is responding poorly to a diuretic).
• High doses of loop diuretic (furosemide 80 mg or equivalent) may cause subsequent difficulties if an angiotensin-converting enzyme inhibitor needs to be started. First-dose hypotension (with dizziness or fainting) is more likely to occur in people taking diuretics, particularly if the dose of diuretic is high [Clementy et al, 1986].
• In addition, high doses of diuretic may result in hypokalaemia and other electrolyte disturbances, and renal impairment and acute renal failure have been reported [Glück et al, 1984; Clementy et al, 1986; De Lepeleire et al, 1988].
• CKS expert reviewers agreed that the dose of a loop diuretic should not exceed furosemide 40 mg (or equivalent) for the management of suspected heart failure, unless on specialist advice.

Specialist

• NICE defines the term 'specialist' as a physician with sub-speciality interest in heart failure (often a consultant cardiologist) who leads a specialist multidisciplinary heart failure team of professionals with appropriate competencies from primary and secondary care. The team will involve, where necessary, other services (such as rehabilitation, tertiary care, and palliative care) in the care of individual persons.