Treatments for chronic heart failure aim to relieve symptoms, reduce mortality and exacerbations and improve exercise tolerance. A range of drugs may be used, most commonly loop diuretics (furosemide, bumetanide, torasemide), thiazide diuretics (bendroflumethiazide, chlortalidone, metolazone, indapamide, xipamide), and angiotension converting enzyme (ACE) inhibitors (captopril, cilazapril, enalapril, fosinopril, lisinopril, perindopril, quinapril, ramipril), but beta-blockers (bisoprolol, carvedilol, nebivolol), aldosterone antagonists (spironolactone, eplerenone), digoxin, isosorbide dinitrate and hydralazine may also be employed.

Dosage Regimen

* Diuretic dosing varies according to the agent being taken. Thiazides usually act within one to two hours, with a duration of action between 12 and 24 hours, so should be taken in the morning to avoid diuresis interfering with sleep. The exception is chlortalidone which has a longer duration of action so it may be taken on alternate days. Loop diuretics act within one hour and diuresis is normally complete within six hours, so they can be administered twice daily if necessary without interfering with sleep.

* ACE inhibitors should be initiated at low doses and slowly titrated upwards until the optimal tolerated/target dose is achieved They are normally taken once daily.

* Beta-blockers should be initiated at a very low dose and titrated very slowly over a period of weeks or months. They are usually administered once daily, but beta-blockers with a short duration of action can be administered up to two or three times a day.

* Aldosterone antagonists are usually taken once daily.

* Digoxin is administered once a day.

Patient's knowledge of the medicine's use

* Diuretics are usually employed first-line for patients with symptoms of acute pulmonary oedema. Dosage can be titrated up or down according to response and need following the introduction of further heart failure therapies.

* ACE inhibitors are routinely used to treat patients with heart failure due to left ventricular systolic dysfunction (LVSD), and should be started before the introduction of beta-blockade.

* Beta-blockers are used to treat heart failure due to LVSD and should only be initiated after diuretic and ACE inhibitor therapy, regardless of whether or not symptoms persist.

* Aldosterone antagonists should only be initiated under specialist advice and are used to treat heart failure due to LVSD in patients who remain moderately to severely symptomatic despite optimal drug therapy.

* Digoxin is recommended for worsening symptoms or severe heart failure due to LVSD, despite combination therapy (diuretic + ACE inhibitor + beta-blocker) and in patients showing signs of atrial fibrillation.

Is the medicine working?

* Has the patient been taking the correct dosage of their medication?

* Has the patients symptoms/condition deteriorated? If so, refer back to the prescriber.

* Is the patient taking any OTC/herbal remedies, which may interact with their medication?

Side effects

* Diuretics can precipitate hypokalaemia which can be dangerous in patients also receiving digoxin. Lower doses of diuretics should be used in the elderly and in patients with impaired renal function. Other side effects of diuretics include mild GI disturbances and postural hypotension.

* ACE inhibitors can cause profound first dose hypotension (in patients taking high doses of diuretics), renal impairment and a persistent dry cough.

* Beta-blockers can cause sleep disturbances, nightmares, fatigue and coldness of the extremeties. Beta-blockers can also precipitate asthma and should be avoided in people with a history of asthma or COPD.

* Aldosterone antagonists can cause gastrointestinal disturbances, impotence, gynaecomastia, menstrual irregularities, lethargy and headache.

* Side effects of digoxin usually occur with excessive dosage and can include anorexia, nausea, vomiting, diarrhoea, visual disturbances, fatigue, drowsiness and confusion.

Monitoring

* Routine monitoring of serum digoxin concentrations is not recommended, but may prove useful to confirm non-compliance if conducted within eight to 12 hours of the last dose. However, these should be interpreted cautiously as digoxin toxicity can occur even when concentrations are within the therapeutic range.

* Patients receiving aldosterone antagonists should have blood potassium and creatinine levels monitored for signs of hyperkalaemia and/or deteriorating renal function at one week, monthly for three months then every three months for up to a year after starting.

* Heart rate, blood pressure, electrolytes, urea and creatinine and clinical status should be assessed after each increment of beta-blocker therapy.

* Monitoring should also include a clinical assessment of functional capacity, fluid status, cardiac rhythm, cognitive and nutritional status.

* ACE inhibitors require biochemical monitoring after every dose change and then every six months.

Lifestyle

* Patients should participate in regular aerobic and/or resistive exercise.

* Patients who smoke should be encouraged to quit.

* Patients should reduce salt intake to less than 6g daily.

* Patients should be offered a "one-off" pneumococcal vaccination and a yearly flu vaccination.

Kevin Alexander, community pharmacist, Hafod Pharmacy, Swansea / AF

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