olanzapine and Muscular-Diseases

We present a 72-year-oldpatient with probable diffuse Lewy body disease and visual hallucinations, who developed subacute reversible "dropped head syndrome" and parkinsonian signs after the introduction of olanzapine at a total daily dose of 10 mg. One week after olanzapine was withdrawn, the patient's posture started to improve. Further improvement was achieved after dopaminergic substitution. Clinical and electrophysiological observations might indicate neck extensor myopathy due to axial rigidity or focal neck dystonia, induced by dopamine receptor blockade.

Topics: Aged; Antipsychotic Agents; Benzodiazepines; Dopamine Antagonists; Female; Hallucinations; Head Movements; Humans; Kyphosis; Lewy Body Disease; Muscular Diseases; Olanzapine

Olanzapine is an atypical antipsychotic that is reported to cause myopathy and raised creatine kinase (CK) levels. The prevalence and severity of acute myopathy after deliberate olanzapine ingestion are unclear. Therefore, we reviewed case notes from 64 consecutive patients admitted to our institution after olanzapine overdose. Overall, serum CK was higher than five times the upper limit of normal in 17% of patients. The prevalence of raised CK values was positively correlated with the stated quantity of olanzapine ingested, suggesting a dose-dependent relationship for acute muscle toxicity. There was an apparent delay of 12 hours or more between olanzapine ingestion and the occurrence of maximum CK. Despite the high prevalence of acute muscle toxicity after olanzapine ingestion, none of the patients developed renal failure.

Topics: Acute Disease; Adult; Antipsychotic Agents; Benzodiazepines; Creatine Kinase, MM Form; Dose-Response Relationship, Drug; Drug Overdose; Female; Humans; Male; Middle Aged; Muscle, Skeletal; Muscular Diseases; Olanzapine; Retrospective Studies; Rhabdomyolysis; Scotland