title: Neuroleptic malignant syndrome in an adolescent with CYP2D6 deficiency.
abstract: We describe a patient with dystonia and psychotic symptoms treated with standard doses of antipsychotics, who developed neuroleptic malignant syndrome (NMS). A 16-year-old male with a history of misuse of dextromethorphan and pseudoephedrine for recreational purpose presented with dystonia and a psychotic episode. Following continuous treatment with olanzapine (10 mg/day), repeated injections of levomepromazine (37.5 mg/day), and a single injection of haloperidol (2.5 mg), the patient developed NMS. Muscular rigidity, fever (up to 41 °C), hypotension (100/70 mmHg), tachycardia (120 beats per minute), tachypnea (26 breaths per minute), elevated leukocyte count (up to 16.6 × 10(3)/μL), and elevated serum creatinine phosphokinase (CPK) (up to 15,255 U/L) were observed. A diagnosis of NMS was made according to the DSM-IV TR criteria. Genotyping revealed that he was homozygous for a non-functional CYP2D6*4 allele. The case highlights the importance of therapeutic drug monitoring in identification and differentiation of drug-induced effects in psychiatric disorder to prevent NMS and its complications. In addition, genotyping of CYP2D6 might be considered in patients with symptoms suggestive of drug toxicity who are treated with neuroleptics metabolized via the CYP2D6 pathway, as carriage of one or more non-functional alleles may increase the risk for adverse reactions, such as NMS.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, PO Box 281, 171 77, Stockholm, Sweden, agnieszka.butwicka@ki.se.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Butwicka
authors.forename: Szymańska
authors.initials: S
authors.lastname: Krystyna
authors.forename: Włodzimierz
authors.initials: W
authors.lastname: Retka
authors.forename: Tomasz
authors.initials: T
authors.lastname: Wolańczyk
mesh_terms: D000293:Adolescent; D019389:Cytochrome P-450 CYP2D6 / Q000172:deficiency* / Q000235:genetics; D004247:DNA / Q000235:genetics; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D005820:Genetic Testing / Q000379:methods; D005838:Genotype; D006720:Homozygote; D006801:Humans; D008297:Male; D009459:Neuroleptic Malignant Syndrome / Q000175:diagnosis / Q000201:enzymology* / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D004247:DNA; D019389:Cytochrome P-450 CYP2D6