Polyuria after olanzapine overdose

Nocturnal enuresis in patients taking clozapine, risperidone, olanzapine and quetiapine: comparative cohort study

BACKGROUND

Nocturnal enuresis has been reported in patients taking clozapine, but the incidence has not been accurately established. The incidence of enuresis in patients taking risperidone, olanzapine or quetiapine is unknown. Aims To compare nocturnal enuresis in patients taking clozapine with that in patients taking risperidone, olanzapine or quetiapine.

METHOD

Observational cohort study using prescription event monitoring methods. Patients prescribed atypical antipsychotic medicines were followed up by questionnaires that were sent to their medical practitioner. Practitioners were asked to directly ask their patients about bed-wetting.

RESULTS

Nocturnal enuresis was reported by 17 of 82 (20.7%) patients taking clozapine, 11 of 115 (9.6%) taking olanzapine, 7 of 105 (6.7%) taking quetiapine and 12 of 195 (6.2%) taking risperidone. Compared with clozapine, the risk of nocturnal enuresis was significantly lower in patients taking olanzapine (odds ratio, OR = 0.43, 95% CI 0.19-0.96), quetiapine (OR = 0.33, 95% CI 0.13-0.59) or risperidone (OR = 0.27, 0.12-0.59), with odds ratios adjusted for age, gender and duration of treatment.

CONCLUSIONS

Approximately one in five patients prescribed clozapine experienced bed-wetting. This was significantly higher than the rate of nocturnal enuresis in patients taking olanzapine, quetiapine or risperidone.

Olanzapine intoxication-related transient diabetes insipidus

Olanzapine is a second-generation atypical antipsychotic agent approved for the treatment of psychotic disorders and mania. The effects of olanzapine intoxication include central nervous system depression, hyperthermia, myosis, tachycardia, and orthostatic hypotension. Heretofore, only one case has been reported to develop polyuria after olanzapine overdose (560 mg). We describe a case that developed diabetes insipidus following massive olanzapine ingestion and returned to normal after desmopressin treatment.

Subcutaneous olanzapine for hyperactive or mixed delirium in patients with advanced cancer: a preliminary study

CONTEXT

Oral olanzapine is effective in controlling agitation in patients with delirium, but often, parenteral administration is necessary. Intramuscular (IM) olanzapine is approved for managing agitation in schizophrenia, but this route is inappropriate for terminally ill patients.

OBJECTIVES

The purpose of this pilot study was to determine the safety and tolerability of subcutaneous (SC) olanzapine in the management of hyperactive or mixed delirium in patients with advanced cancer.

METHODS

We conducted a prospective open-label study in patients with advanced cancer who had agitated delirium (Richmond Agitation Sedation Scale [RASS] score ≥+1) that had not responded to a 10mg or higher dose of parenteral haloperidol over 24 hours. Patients received olanzapine 5mg SC every eight hours for three days and continued haloperidol for breakthrough agitation. For patients requiring more than 8mg of rescue haloperidol daily, the olanzapine dose was increased to 10mg SC every eight hours. Injection site, systemic toxicity, and efficacy (RASS score <+1 and total haloperidol dose <8mg per 24 hours on the last study day) were evaluated.

RESULTS

Twenty-four patients received at least one olanzapine injection, and 15 (63%) completed the study. Median age of evaluable patients was 58 years (range 49-79), and 67% were males. No injection site toxicity was observed after 167 injections. Probable systemic toxic effects were observed in four patients (severe hypotension [blood pressure <90/50mmHg], paradoxical agitation, diabetes insipidus, and seizure). Efficacy was achieved in nine (37.5%) patients.

CONCLUSIONS

IM olanzapine is well tolerated subcutaneously. Further research is needed to evaluate its efficacy in controlling agitated delirium.

A systematic review of cardiovascular effects after atypical antipsychotic medication overdose

As the use of atypical antipsychotic medications (AAPMs) increases, the number of overdoses continues to grow. Cardiovascular toxicity was common with older psychiatric medications but seems uncommon with AAPM. We conducted a systematic literature review to describe the cardiovascular effects reported after overdose of 5 common AAPM: aripiprazole, olanzapine, quetiapine, risperidone, and ziprasidone. We included case reports and case series describing overdose of these 5 medications identified in a search of MEDLINE, EMBASE, and abstracts from major toxicology meetings. We found 13 pediatric cases (age, <7 years), 22 adolescent cases (age, 7-16 years), and 185 adult cases. No pediatric case described a ventricular dysrhythmia or a cardiovascular death. In the adolescent and adult cases, we found numerous reports of prolonged corrected QT interval and hypotension, but there were only 3 cases of ventricular dysrhythmia and 3 deaths that may have been due to direct cardiovascular toxicity. The results from case series reports were similar to the single case report data. Our review suggests that overdose of AAPM is unlikely to cause significant cardiovascular toxicity.

Diabetes insipidus following overdose of baclofen and quetiapine

We report the case of a patient who presented with coma in the context of baclofen and quetiapine overdose. While the clinical picture was largely in keeping with previous descriptions of baclofen and quetiapine toxicity, the patient went on to exhibit clinical and biochemical features of cranial diabetes insipidus, a finding which has not previously been described in this context.

Overdoses and ingestions of second-generation antipsychotics in children and adolescents

OBJECTIVE

We reviewed the available published data on intentional or unintentional secondgeneration antipsychotic overdoses in children and adolescents. The prescribing of secondgeneration antipsychotics has continued to increase over the past decade for children, adolescents, and adults. The authors reviewed the existing literature to determine the circumstances, presenting problems, treatment, and outcomes of youths who were exposed to nontherapeutic doses of these medications.

METHODS

A systematic English-language Medline search of all reports (1989-2005) and a review of the bibliographies of all articles obtained was done to identify papers reporting an overdose or ingestion of a second-generation antipsychotic. Data were reviewed on clozapine, risperidone, olanzapine, ziprasidone, quetiapine, and aripiprazole. The annual reports of the American Association of Poison Control Centers National Data Collection System were reviewed from 1990 to 2003, the most recent report currently available. All fatalities in children and youths under 18 years of age were included.

RESULTS

The literature review identified 40 reports that included 63 patients, ranging in age from 1 day to 17 years of age. The clinical presentations included drowsiness, lethargy, agitation, irritability, combativeness, and tachycardia. There were 11 fatalities in the cases reviewed, 1 from clozapine overdose, 3 from risperidone overdose, 2 from olanzapine overdose, and 5 from quetiapine overdose. All other cases reported no significant sequelae and resolved without any reported clinical consequences. Duration of overdose symptoms ranged from 24 hours to 7 days. One case of clozapine intoxication showed resolution of symptoms in 6 hours and, in another case of olanzapine overdose, symptoms resolved in 13 days. The most frequently employed treatments included intubation, gastric lavage, activated charcoal, intravenous fluids, artificial respiration, and restraints or sedatives.

CONCLUSIONS

There is a need for future case reports to include serum medication level, weight of patient, coingestants, the health of the patient at baseline, relevant laboratory and toxicology studies and a standardized scale to rate the level of consciousness, such as the Glasgow Coma Scale. The existing pharmacovigilance data reports indicate these medications are relatively safe when taken in overdose, particularly when coingestants are not involved.