Psychiatric drug induced syndromes Dr Jason Ward

Acute Dystonia Sustained abnormal postures or muscle spasms that develop within 7 days of starting antipsychotic medication 95% cases within 96 hours Pathogenesis unclear –possibly D2 receptor blockade in caudate, putamen & globus pallidus

Risk factors Young age Male Previous episode Recent cocaine use ? Race ? Presence of affective disorder Dehydration, hypocalcaemia, hypoparathyroidism

Clinical Features Any muscle group Head & neck common Torticollis Trismus Grimacing Dysarthria Blepharospasm Swallowing difficulties Oculogyric crisis * Opisthotonus Laryngospasm & stridor * Can occur on stable dose

Differential Diagnosis Psychogenic dystonia Catatonia - mutism, akinesis, rigidity Tardive dystonia - months after treatment Hypocalcaemia Temporal epilepsy

Drug causes Antipsychotics Antiemetics Antidepressants - SSRIs Case reports of others –carbemazepine, phenytoin, diazepam

Treatment Anticholinergic im –procyclidine 5mg, usually effective 20mins –occasionally 2nd/3rd dose Or antihistamine –promethazoine 50mg Oculogyric crisis - can add clonazepam Continue for 4-7 days

Serotonin Syndrome Syndrome of rigidity, myoclonus, hyperreflexia, nausea & vomiting, autonomic instability, hyperthermia confusion, agitation, delirium, coma Aetiology excess 5-HT ? 5-HT 1A Unknown incidence

Drug causes SSRI with MAOI High dose SSRIs Combination of SSRIs St John’s Wort + antidepressant Also MAOI + pethidine, dextromethorphan

Treatment Stop drug - usually settles in 24 hours Cooling Fluids if hypotensive Clonazepam for myoclonus ? Cyproheptadine ? Propranolol ?methysergide

Neuroleptic Malignant Syndrome Severe muscle rigidity and elevated temperature in an individual using neuroleptic medication Accompanied by >2 –sweating, dysphagia, tremor, incontinence, mutism, tachycardia, labile BP, change in level of consciousness, elevated WCC/CPK

Risk Factors Prior episode Dehydration, warm ambient temperature High potency neuroleptic or rapid rise in dose im injection Male:Female 2:1 All ages (45% 20-39) 90% within first 10 days of treatment

Treatment Stop neuroleptics Control fever Fluid balance Benzodiazepines ? Bromocriptine ? Dantrolene Re-challenge with neuroleptic after 2 weeks

References Van Harten PN, Hoek HW, Kahn RS. Acute dystonia induced by drug treatment. BMJ 1999;319:623-6 Sternbach H. The Serotonin Syndrome. Am J Psychiatry 1991;148: Bristow MF, Kohen D. How malignant is the neuroleptic malignant syndrome? BMJ 1993;307: Carbone JR. The neuroleptic malignant and serontonin syndromes. Emer Med Clin N America 2000;18:317-25