Analysis of pregnanediol in urine: trental interference

Patients given Trental (pentoxifyllin, Hoechst A.G.) for the treatment of vascular disorders excrete a substance which interferes with the gas chromatographic anlaysis of pregnanediol. The interfering substance appeared in urine within 4-5 h of the ingestion of 100 mg Trental, and was cleared during the next 4-10 h. The administration of 300 mg/24 h to an anovulatory woman caused an apparent increase in her output of pregnanediol of from less than 1 to 65.8 micronmol/24 h.