Misleading T3-test values in psychiatric patients treated with orphenadrine.
Thyroid laboratory tests were assessed in 74 psychiatric patients without clinical evidence of overt thyroid disorder. In a first screening of 42 patients, 13 were found to have elevated levels of triiodothyronine uptake test (T3-test) by a Sephadex method. Ten of these patients also had an elevated free thyroxine index (fT4-index). Of the 13 patients with increased T3-test values, 10 were on orphenadrine (Disipal) treatment or had recently stopped taking the drug. In a second study, thyroid function tests were compared in 15 pairs of matched psychiatric patients treated with orphenadrine or other anticholinergic drugs. Values of T3-test and free thyroxine index were significantly higher among patients treated with orphenadrine. Finally, orphenadrine was instituted in four patients and withdrawn in six patients. T3-test values and free thyroxine indices increased gradually after orphenadrine treatment had been initiated and decreased gradually when it was withdrawn.
Department of Internal Medicine, Umeå University Hospital, Sweden.
E
E
Moberg
E
E
Hägg
K
K
Asplund
K
K
Grankvist
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009966:Orphenadrine / Q000008:administration & dosage / Q000009:adverse effects*; D010276:Parasympatholytics / Q000008:administration & dosage; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood*
D010276:Parasympatholytics; D014284:Triiodothyronine; D013972:Thyrotropin; D009966:Orphenadrine; D013974:Thyroxine