Black Hairy Tongue Associated with Olanzapine Treatment: A Case Report LUT TAMAM, M.D. 1 , AND BILGE BURCAK ANNAGUR, M.D. 2 Abstract Olanzapine is an atypical antipsychotic drug approved for acute and long-term treatment of bipolar disorder. Although relatively safe as compared to other classical antipsychotic medications, there are a number of uncommon adverse effects of olanzapine such as oral cavity lesions. In addition to the relatively common side effect of dry mouth, several articles have reported an association between olanzapine treatment and the development of oral lesions such as apthous stomatitis, pharyngitis, glossitis and oral ulcera- tion. Although there are several cases in which the tongue was affected in conjunction with stomatitis or pharyngitis, we could not find a case report indicating a direct relationship between olanzapine use and a tongue lesion. We present here the case of a patient with bipolar disorder, who developed recurrent black hairy tongue on two different occasions following the addition of olanzapine to lithium treatment. In the present case, xerostomia (dry mouth), which is an adverse reaction of both olanzapine and lithium, may have played a role in the development of black hairy tongue. All agents with a possible side effect of xerostomia may predispose patients to black hairy tongue, especially when they are administered in combination. To preclude the development of this complica- tion with such drugs, extra time and effort should be given to improving oral hygiene. Key Words: Black hairy tongue, olanzapine, lithium, xerostomia, dry mouth, bipolar disorder, adverse effect. Introduction OLANZAPINE is an atypical antipsychotic drug ap- proved for the acute and long-term treatment of bipolar disorder (1). It is considered an atypical an- tipsychotic because it alters affinities for serotonin and dopamine receptors. The most common ad- verse effects of olanzapine are somnolence, ortho- static hypotension, headache, constipation, weight gain, mild hyperglycemia, hypertriglyceridemia, extrapyramidal symptoms, dyspepsia and dry mouth (1, 2). Apart from these common side ef- fects, there are a number of uncommon adverse ef- fects of olanzapine, such as oral cavity lesions (3). Specifically, several authors have reported an as- sociation between olanzapine treatment and the de- velopment of such oral lesions as apthous stomati- tis, pharyngitis, glossitis and oral ulceration (3, 4). Although several cases have been reported in which the tongue is affected in conjunction with stomatitis or pharyngitis (4), we could not find an article reporting a direct relationship between olanzapine use and a tongue lesion. In this article, we present the case of a patient with a diagnosis of bipolar disorder, who devel- oped recurrent black hairy tongue (BHT) on two different occasions following the addition of olan- zapine to her treatment. Case Report A 25-year-old woman who presented with manic symptoms (i.e., euphoria, overtalkativeness, insomnia, grandiosity) to the emergency room, was admitted to our psychiatry inpatient clinic with a diagnosis of bipolar disorder I. Her psychi- atric history revealed that the current admission was her fifth hospitalization since the beginning of her illness six years previously. Since her first episode, almost every year she had discontinued her treatment without consulting her physician. Each time, her nonadherence was eventually fol- lowed by the recurrence of manic symptoms and ended with hospitalization. During the first three hospitalizations, her symptoms were stabilized © THE MOUNT SINAI JOURNAL OF MEDICINE Vol. 73 No. 6 October 2006 891 1 Associate Professor, Department of Psychiatry, and 2 Resident, Department of Psychiatry, Cukurova University Faculty of Medi- cine Adana, Turkey. Address all correspondence to Lut Tamam, M.D., Cukurova University Faculty of Medicine, Department of Psychiatry, Bal- cali, 01330 Adana, Turkey; e-mail: Ltamam@mail.cu.edu.tr, Lta- mam@yahoo.com Accepted for publication February 2006.