To the Editor: We report two cases of previously well male bodybuilders who presented with severe extrapyramidal reactions after intramuscular injection of the antipsychotic fluphenazine decanoate, in the mistaken belief that it was an anabolic steroid.

The first patient, aged 31 years, obtained fluphenazine decanoate from a gym contact. He injected 50 mg intramuscularly on alternate days (Days 1, 3 and 5) to a total of 150 mg, then presented to two local hospitals on Days 7 and 11 with difficulty swallowing, generalised muscle stiffness and lethargy. He withheld the history of fluphenazine use, and was diagnosed with tonsillitis. On Day 14, he presented to our emergency department (ED) with marked dystonia, immobility, and inability to speak or swallow food. On examination, he was afebrile and haemodynamically stable. He was given a trial dose of benztropine 2 mg, but improvement was slight and, given the absence of relevant history, benztropine was not repeated. The neurology team raised the possibility of a conversion disorder, but the psychiatry team, noting the patient’s attempts to speak and an absence of recent stressors, believed that further investigation into an organic cause was required. When the patient’s wife learned that he had used fluphenazine and alerted the neurology team to this use, he was started on regular benztropine and his condition improved over the next 3 days. The dose of benztropine was reduced on discharge, but his dystonia recurred and required readmission to hospital for further treatment.

The second, unrelated patient, also aged 31 years, openly admitted purchasing fluphenazine decanoate from “a friend of a friend”. After injecting two 50 mg depots, he had multiple presentations to three EDs, where he was treated for dystonia with immediate doses and then regular low doses of benztropine. On admission to our hospital 19 days after injection, he was afebrile and haemodynamically stable, with marked dystonia. His initial creatine kinase level was elevated (553 U/L; normal, < 204 U/L), but subsequently normalised and was not accompanied by autonomic dysfunction. His condition improved with regular oral diazepam and benztropine, but symptoms recurred when he inappropriately reduced his benztropine dose after discharge.

On subsequent review, both patients’ dystonia was resolving, but they had significant akathisia.

Inadvertent and inappropriate use of a long-acting phenothiazine not only required prolonged anticholinergic therapy for these men, but we believe placed them at risk of neuroleptic malignant syndrome. We have found no previous similar reports in the medical literature, but are aware anecdotally of at least one other case of a patient treated recently at a district hospital.

The anabolic steroid nandrolone decanoate is referred to colloquially on numerous websites and by our patients as “deca” (from the Organon brand name Deca-Durabolin). We believe our patients and their supplier(s) have mistaken the “decanoate” in fluphenazine decanoate for the pharmacologically active component of the drug.