myocarditis. Therapy consists of volume loading, vasodilator
or inotropic drugs.
Chronic heart failureis initially treated with aloop
diuretic, usually furosemide supplemented with
spironolactone, amiloride hydrochloride p. 142 ,or
potassium chloride p. 601.
If diuresis with furosemide is insufficient, the addition of
metolazone p. 142 or athiazide diureticcan be considered.
With metolazone the resulting diuresis can be profound and
care is needed to avoid potentially dangerous electrolyte
disturbance.
If diuretics are insufficient an ACE inhibitor, titrated to the
maximum tolerated dose, can be used.ACE inhibitorsare
used for the treatment of all grades of heart failure in adults
and can also be useful for children with heart failure.
Addition of digoxin p. 81 can be considered in children who
remain symptomatic despite treatment with a diuretic and
an ACE inhibitor.
Some beta-blockers improve outcome in adults with heart
failure, but data on beta-blockers in children are limited.
Carvedilol p.^125 has vasodilatory properties and therefore
(like ACE inhibitors) also lowers afterload.
In children receiving specialist cardiology care, the
phosphodiesterase type- 3 inhibitor enoximone p. 127 is
sometimes used by mouth for its inotropic and vasodilator
effects. Spironolactone is usually used as a potassium-
sparing drug with a loop diuretic; in adults low doses of
spironolactone are effective in the treatment of heart failure.
Careful monitoring of serum potassium is necessary if
spironolactone is used in combination with an ACE inhibitor.
Thiazides and related diuretics
Thiazides and related compounds are moderately potent
diuretics; they inhibit sodium reabsorption at the beginning
of the distal convoluted tubule. They are usually
administered early in the day so that the diuresis does not
interfere with sleep.
In the management ofhypertensiona low dose of a thiazide
produces a maximal or near-maximal blood pressure
lowering effect, with very little biochemical disturbance.
Higher doses cause more marked changes in plasma
potassium, sodium, uric acid, glucose, and lipids, with little
advantage in blood pressure control. Thiazides also have a
role in chronic heart failure.
Bendroflumethiazide p. 111 is licensed for use in children;
chlorothiazide p. 111 is also used.
Chlortalidone p. 142 , a thiazide-related compound, has a
longer duration of action than the thiazides and may be
given on alternate days in younger children.
Metolazone is particularly effective when combined with a
loop diuretic (even in renal failure) and is most effective
when given 30 – 60 minutes before furosemide profound
diuresis can occur and the child should therefore be
monitored carefully.
Loop diuretics
Loop diuretics inhibit reabsorption of sodium, potassium,
and chloride from the ascending limb of the loop of Henlé in
the renal tubule and are powerful diuretics.
Furosemide and bumetanide p. 140 are similar in activity;
they produce dose-related diuresis. Furosemide is used
extensively in children. It can be used for pulmonary oedema
(e.g. in respiratory distress syndrome and
bronchopulmonary dysplasia), congestive heart failure, and
in renal disease.
Potassium-sparing diuretics and aldosterone
antagonists
Spironolactone is the most commonly used potassium
sparing diuretic in children; it is an aldosterone antagonist
and enhances potassium retention and sodium excretion in
the distal tubule. Spironolactone is combined with other
diuretics to reduce urinary potassium loss. It is also used in
nephrotic syndrome, the long-term management of Bartter’s
syndrome, and high doses can help to control ascites in
babies with chronic neonatal hepatitis. The clinical value of
spironolactone in the management of pulmonary oedema in
preterm neonates with chronic lung disease is uncertain.
Potassium canrenoate p. 126 given intravenously, is an
alternative aldosterone antagonist that may be useful if a
potassium-sparing diuretic is required and the child is
unable to take oral medication. It is metabolised to
canrenone, which is also a metabolite of spironolactone.
Amiloride hydrochloride on its own is a weak diuretic. It
causes retention of potassium and is therefore given with
thiazide or loop diuretics as an alternative to giving
potassium supplements.
A potassium-sparing diuretic such as spironolactone or
amiloride hydrochloride may also be used in the
management of amphotericin-induced hypokalaemia.
Potassium supplements mustnotbe given with
potassium-sparing diuretics. Administration of a potassium-
sparing diuretic to a child receiving an ACE inhibitor or an
angiotensin-II receptor antagonist can also cause severe
hyperkalaemia.Potassium-sparing diuretics with other diuretics
Although it is preferable to prescribe diuretics separately in
children, the use offixed combinations may be justified in
older children if compliance is a problem. (Some
preparations may not be licensed for use in children—
consult product literature).Other diuretics
Mannitol p. 141 is used to treat cerebral oedema, raised
intraocular pressure, peripheral oedema, and acites.
The carbonic anhydrase inhibitor acetazolamide p. 683 is a
weak diuretic although it is little used for its diuretic effect.
Eye drops of dorzolamide p. 684 and brinzolamide p. 684
inhibit the formation of aqueous humour and are used in
glaucoma. Acetazolamide is used in the treatment of
epilepsy, and raised intracranial pressure.Diuretics with potassium
Diuretics and potassium supplements should be prescribed
separately.DIURETICS›LOOP DIURETICS
Loop diuretics f
lDRUG ACTIONLoop diuretics inhibit reabsorption from the
ascending limb of the loop of Henlé in the renal tubule and
are powerful diuretics.
lCONTRA-INDICATIONSAnuria.renal failure due to
nephrotoxic or hepatotoxic drugs.severe hypokalaemia.
severe hyponatraemia
lCAUTIONSCan cause acute urinary retention in children
with obstruction of urinary outflow.can exacerbate
diabetes (but hyperglycaemia less likely than with
thiazides).can excacerbate gout.comatose and
precomatose states associated with liver cirrhosis.
hypotension should be corrected before initiation of
treatment.hypovolaemia should be corrected before
initiation of treatment
CAUTIONS, FURTHER INFORMATION
▶Potassium lossHypokalaemia can occur with both thiazide
and loop diuretics. The risk of hypokalaemia depends on
the duration of action as well as the potency and is thus
greater with thiazides than with an equipotent dose of a
loop diuretic.
Hypokalaemia is particularly dangerous in children
being treated with cardiac glycosides. In hepatic failureBNFC 2018 – 2019 Oedema 139
Cardiovascular system2