Accelerated Renal Elimination of Thallium in the Rat Due to Treatment with Furosemide or Potassium Ions

Abstract

It has been attempted to accelerate the elimination of thallium via the faecal route. In this respect the administration of prussian blue is the therapy of choice (Rauws, A. G., Naunyn-Schmiedeberg’s, Arch. Pharmacol., 284, 295–306 (1974)).

However, the renal pathway also plays an important part in the excretion of thallium, but has never been a subject of systematical investigation from a therapeutic point of view.

We have attempted to promote the renal elimination of thallium by treatment with several diuretic agents and by changing the sodium and potassium intake in rats.

Male Wistar rats (weight 220–250 g) received one single oral dose of 10 mg (= 48.9 μmol) Tl per kg body weight as Tl₂SO₄ and if therapy took place, the treatment with diuretic agents started one hour after thallium administration.

Urine weight as well as the urinary concentrations of Tl⁺, Na⁺, K⁺ and Cl^- were determined quantitatively during at least one week. The diuretics chosen were furosemide (6 and 30 mg/kg), triamterene (25 mg/kg), acetazolamide (30 mg/kg) and canrenoate (25 and 50 mg/kg), twice daily.

The control rats excreted about 20% of the ingested thallium within one week. Furosemide (30 mg/kg) proved to be the most effective diuretic drug with respect to the elimination of thallium: approximately 35% of the administered dose was excreted in the urine in the same period. The potassium retaining diuretic agents triamterene and canrenoate and the carbonic anhydrase inhibitor acetazolamide did not accelerate the thallium excretion. There was no relationship between the volume of the urine produced and the amount of thallium excreted.

In the experimental model used, triamterene and canrenoate did not retain potassium and thallium compared to the controls.

Experiments with 390 mmol Na and 230 mmol K in the food (normal composition 110 mmol Na, 230 mmol K) showed no influence on the renal excretion of both thallium and potassium. However, when the amount of K in the normal food was increased to 650 mmol, the renal excretion of thallium in one week was raised to 55% of the administered dose.

In summary, the renal elimination of thallium in the conscious rat can be significantly accelerated by treatment with furosemide. The amount of water excreted under influence of diuretic drugs has no predictive value for the result desired. On the other hand, chronic oral administration of potassium chloride proves to be superior to any other treatment with respect to the enhanced renal elimination of thallium.