Is there any difference between amiloride-hydrochlorthiazide and furosemide in causing gout?/nBackg

Fråga: Is there any difference between amiloride-hydrochlorthiazide and furosemide in causing gout?

Background: A 73-year-old woman with hypertension has previously during five years been treated with amiloride-hydrochlorthiazide. Two years ago the patient had an attack of gout and the treatment was changed to furosemide. The patient has now again symptoms of gout.

Sammanfattning: Diuretic-induced hyperuricemia is one important cause of secondary gout. One case-control study has found that gout was more strongly associated with the use of loop diuretics than thiazides in hypertensive patients.

Svar: Though an extensive literature search has been performed little has been found concerning studies comparing the incidence of gout between amiloride-hydrochlorthiazide and furosemide. Most of the existing studies have looked upon hyperuricemia and diuretics. However, not all hyperuricemic patients develop gout (1).

Some diuretics are not considered to cause hyperuricemia, eg amiloride and spironolactone (1-3). However, one has seen that an increase in serum uric acid was greater with hydrochlorthiazide combined with amiloride than with hydrochlorthiazide alone, indicating that amiloride may influence uric acid secretion (4).

A case-control study has been performed by Waller and Ramsey (5).

Seventy hypertensive patients with acute gout during diuretic treatment were identified and matched for age and sex to 140 hypertensive controls who took diuretics but did not develop gout. Gout was related more strongly to the use of loop diuretic than thiazides, with 30 per cent of cases taking a loop-diuretic compared to 14 per cent of controls. Since loop diuretics are used more frequently in patients with impaired renal function this could have lead to the false conclusion that loop diuretics are more associated with development of gout than thiazides. Therefore the authors investigated if the renal function could explain the association. The relationship between gout and loop diuretics was present at all levels of renal function, in particular in those patients with normal serum creatinine values.

In the files of the Swedish Adverse Drug Reactions Advisory Committee there are reports of gout on amiloride, hydrochlorthiazide and furosemide judged possible or probable.

In this patient there are several ways to handle the situation.

Hypertension can often be managed with drugs other than diuretics, eg beta-adrenergic blocking agents, angiotensin-converting enzyme inhibitors and calcium channel entry blockers. If it is considered necessary to continue with a diuretic, the urate level can be controlled by appropriate drug treatment.