Hypothyroidism and Phenytoin Intoxication
Authors: JAMES P. FINNERTY
Journal: Annals of Internal Medicine (1985)

Letters and Corrections1 October 1985Hypothyroidism and Phenytoin IntoxicationJAMES P. FINNERTY, M.R.C.P.JAMES P. FINNERTY, M.R.C.P.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-103-4-639_2 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptTo the editor: Regarding the recent brief report by Kushnir and colleagues (1), I should like to question the authors' discussion and conclusions. They state that the phenytoin had uncovered "occult primary hypothyroidism" and adduce as evidence an exaggerated thyrotrophin response to a thyrotrophin-releasing hormone test done only 2 weeks after the phenytoin therapy was discontinued. Occult or preclinical primary hypothyroidism usually denotes the findings of a normal thyroxine level and an elevated basal thyrotrophin level in a clinically euthyroid patient (2). This patient's thyrotrophin level had rapidly fallen to within the normal range, making occult disease very unlikely. In...References1. KUSHNIRWEINSTEINLANDAUSHAVITBECHARGADOTH MRBGMN. Hypothyroidism and phenytoin intoxication. Ann Intern Med. 1985;102:341-2. LinkGoogle Scholar2. EVEREDHALL DR. Hypothyroidism. Br Med J. 1972;1:290-3. CrossrefMedlineGoogle Scholar3. BAUERBLOUIN LR. Age and phenytoin kinetics in adult epileptics. Clin Pharmacol Ther. 1982;31:301-4. CrossrefMedlineGoogle Scholar4. STOCKIGTTOPLISSBARLOWWHITEHURLEYTAFT JDJEDP. Familial euthyroid thyroxine excess: an appropriate response to abnormal thyroxine binding associated with albumin. J Clin Endocrinol Metab. 1981;53:353-9. CrossrefMedlineGoogle Scholar1. BLACKSHEARESCHULZNAPIERSTUART JAJD. Thyroxine replacement requirements in hypothyroid patients receiving phenytoin. Ann Intern Med. 1983;99:341-2. LinkGoogle Scholar2. AANDERUDSTRANDJORD SR. Hypothyroidism induced by antiepileptic therapy. Acta Neurol Scand. 1980;61:330-2. CrossrefMedlineGoogle Scholar3. SURKSORDENEMANNKUMARA-SIRI MKDM. Diphenylhydantoin inhibits the thyrotropin response of thyrotropin-releasing hormone in man and rat. J Clin Endocrinol Metab. 1983;56:940-5. CrossrefMedlineGoogle Scholar4. HOUGHTONRICHENSLEIGHTON GAM. Effects of age, height, weight and sex on serum phenytoin concentration in epileptic patients. Br J Clin Pharmacol. 1975;2:251-6. CrossrefMedlineGoogle Scholar5. SHERWINLOYNDBOCKSOKOLOWSKI AJGC. Effects of age, sex, obesity and pregnancy on plasma diphenylhydantoin levels. Epilepsia. 1974;15:507-21. CrossrefMedlineGoogle Scholar6. LARSEN-REED P. Thyroid hormone concentrations. In: WERNER SC, INGBAR SH, eds. The Thyroid. 4th ed. New York: HarperRow Publishers; 1978. Google Scholar7. DAM M. Phenytoin toxicity. In: WOODBURY DM, PENRY JK, PIPPENGER CE, eds. Antiepileptic Drugs. New York: Raven Press; 1982. Google Scholar This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAffiliations: Hope Hospital Salford M6 8HD England PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics 1 October 1985Volume 103, Issue 4Page: 639-640KeywordsHormonesHypothyroidismIntoxicationThyroxine Issue Published: 1 October 1985 PDF DownloadLoading ...