DRUGS AND LABORATORY TESTS

Propranolol metabolite interferes with bilirubin estimation in chronic renal failure Frozen sera from 13 of 21 patients with raised serum bilirubin (by diazo technique) and chronic renal failure were retested using a diazo technique and a Bilirubinometer. All but I of the sera from patients on propranolol showed abnormal diazo reactions but gave normal Bilirubinometer results. The samples from 2 patients nO( on propranolol showed raised bilirubin levels by both methods. 'Thus oll ihe patients with 'lafu bilirubin" were taking propranolol. ' It was found that propranolol itself did not interfere

with the diazo reaction, but 2 of its metabolites gave false-positive resUlts. One oflhese, 4-hydroxypropranolol. is a major hepatic metabolite and is excreted in urine as glUcuronide and sulfate conjugates. This error can be avoided by using a Bilirubinometer. AI·Damll.lji, S. and Meek. J .H.: Brilish Medical JOl.lmal280: 1414 (14 Jl.ln 1980)

Methyldopa does not modify glucose test results Either the copper sulfate reduction ('Oinitest'; Ames) or glucose oxidase test ('Tes·Tape', Eli Lilly; 'Qinistix', Ames) for glucose in urine may be used in diabetic patients on methyldopa without drug modification of the resUl ts. In an in vi/ro study, there were no false-positives except with saturated solutions of methyldopa. Tests on the urine of patients on methyldopa also gave no false­positive results. Ives, TJ . et al .: American Journal of . Iospital Pharmacy 37: 683 (May 1980)

Nomifensine: an aid in diagnosis of pituitary adenoma? Nomifensioe (200mg orally) induced a significant decrease in prolactin levels in 23 normoprolactinemic women. This occurred more rapidly and to a greater degree in subjects with 'high' prolactin levels than in those with 'low' levels. A si milar clearcut decrease in prolactin levels followed 200mg of nomifensine in 9 puerperal women (poslporiUm day 2). The same dose of nomi fensine in 47 subjects with pathological hyperprolactinemia showed that 36 were non-responders, and I I responders. 22 of the non-responders had prolactin·secreting pituitary tumors and only 5 of the 14 who did not undergo surgery had no radiological alteration of the seUa turcica. In oontrast, 10 of 11 responders to nomifensine had radiolOgical1y normal sella turcica. Bromocriptine caused a striking fall in prolactin levels in aU 39 hyperproiactinemic patients tested. Nomifensine seems to be able to discriminate between patients with and without pituitary adenoma. Cenanan;, A.R. et aI.' Acta EndocrinoJosia 9l: 139 (Feb 1980)

14 INPHARMA2IJu,, 1980 01S6· 2703/SO/0621..oo\4 $00.50/0 CADIS Press