[The effects of phenylbutazone on the decrease of lithium clearance]

During the treatment of a manic depressive patient, the authors reported some lithium toxicity signs, as lithium carbonate (3 X 300 mg p.d.) and phenylbutazone suppository (3 X 250 mg/p.d.) were associated, this last medication being prescribed for a phlebitis. Lithiemia increased from .70 to 1,44 mEq/l., the lithiemia clearance falling from 10 ml to 5 ml/mn/1.73 m2) and the lithium tubular reabsorption percentage increasing from 85 to 94% (standard rates: 77.4 +/- 1.3%). In a second time, a rat experimentation corroborated these findings: phenylbutazone treatment (100 mg/kg/p.o. for five days) resulted in a lithium tubular reabsorption increase. It seems that the association of lithium carbonate with phenylbutazone should be avoided. The authors point out the risk of prescribing lithium and pyrazolic by-products as phenylbutazone, which are potentially nephrotoxic.