Clozapine in primary care

Chromatographic Methods for the Analysis of the Antipsychotic Drug Clozapine and Its Major Metabolites: A Review

Clozapine (CLZ), a second-generation antipsychotic, can effectively reduce schizophrenia, bipolar disorder and major depression symptoms. This review provides an overview of all reported chromatographic methods (62 references) for the quantification of CLZ and its two main metabolites, norclozapine and clozapine N-oxide in pharmaceutical formulations, biological matrices and environmental samples.

On- and off-label utilisation of antipsychotics in Australia (2000-2021): Retrospective analysis of two medication datasets

OBJECTIVE

To determine antipsychotic utilisation patterns in Australian adults from 2005 to 2021, with a focus on on-label and off-label prescriptions.

METHODS

We examined antipsychotic dispensing trends in adults from 2005 to 2021 using a 10% sample of the Pharmaceutical Benefits Scheme (PBS) dataset, which contains patient-level information on medicines dispensed throughout Australia. The lack of diagnostic information in PBS was substituted by analysing BEACH (Bettering the Evaluation And Care of Health) dataset, a cross-sectional national survey from 2000 to 2016, consisting of data from general practitioner-patient encounters.

RESULTS

There were 5.6 million dispensings for 164,993 patients in PBS throughout this period; 69% patients had >1 dispensing, with a median of 6 per patient. Calculating the estimated period of exposure gave a total of 693,562 treatment episodes, with a median duration of 80 days. There were steady increases in both the incidence and prevalence of antipsychotic dispensings, mainly due to oral second-generation antipsychotics. The most commonly prescribed antipsychotics were quetiapine, olanzapine and risperidone, with a significant portion of patients receiving low-dose quetiapine without dose titration. Analysis of diagnostic indications from BEACH indicated that 27% of antipsychotic prescriptions were off-label for indications such as depression, dementia, anxiety and insomnia, at much lower prescribed daily dosages.

CONCLUSION

The increasing prescribing and off-label use highlights concerns about chronic adverse effects caused by antipsychotics. The combined analysis of medication dispensings and the diagnostic indications for which they are prescribed is a novel approach and throws a spotlight on the need for additional monitoring of antipsychotics.

Barriers and facilitators to the participation and engagement of primary care in shared-care arrangements with community mental health services for preventive care of people with serious mental illness: a scoping review

BACKGROUND

People with serious mental illness die about 20 years earlier than the general population from preventable diseases. Shared-care arrangements between general practitioners and mental health services can improve consumers' access to preventive care, but implementing shared care is challenging. This scoping review sought to describe current evidence on the barriers and facilitators to the participation and engagement of primary care (specifically general practitioners) in shared-care arrangements with community mental health services for preventive health care of this population.

METHODS

We searched Medline, Embase, CINAHL, Scopus, APA PsychINFO and EBM Reviews from 2010 to 2022. Data was extracted against a Microsoft Excel template developed for the review. Data was synthesised through tabulation and narrative methods.

RESULTS

We identified 295 records. After eligibility screening and full-text review, seven studies were included. Facilitators of engagement included a good fit with organisation and practice and opportunities to increase collaboration, specific roles to promote communication and coordination and help patients to navigate appointments, multidisciplinary teams and teamwork, and access to shared medical/health records. Barriers included a lack of willingness and motivation on the part of providers and low levels of confidence with tasks, lack of physical structures to produce capacity, poor alignment of funding/incentives, inability to share patient information and challenges engaging people with severe mental illness in the service and with their care.

CONCLUSION

Our results were consistent with other research on shared care and suggests that the broader literature is likely to be applicable to the context of general practitioner/mental health services shared care. Specific challenges relating to this cohort present difficulties for recruitment and retention in shared care programs. Sharing "goals and knowledge, mutual respect" and engaging in "frequent, timely, accurate, problem-solving communication", supported by structures such as shared information systems are likely to engage primary care in shared care arrangements more than the traditional focus on incentives, education, and guidelines.

Use of Primary Care Data in Research and Pharmacovigilance: Eight Scenarios Where Prescription Data are Absent

The use of primary care databases has been integral in pharmacoepidemiological studies and pharmacovigilance. Primary care databases derive from electronic health records and offer a comprehensive description of aggregate patient data, from demography to medication history, and good sample sizes. Studies using these databases improve our understanding of prescribing characteristics and associated risk factors to facilitate better patient care, but there are limitations. We describe eight key scenarios where study data outcomes can be affected by absent prescriptions in UK primary care databases: (1) out-of-hours, urgent care and acute care prescriptions; (2) specialist-only prescriptions; (3) alternative community prescribing, such as pharmacy, family planning clinic or sexual health clinic medication prescriptions; (4) newly licensed medication prescriptions; (5) medications that do not require prescriptions; (6) hospital inpatient and outpatient prescriptions; (7) handwritten prescriptions; and (8) private pharmacy and private doctor prescriptions. The significance of each scenario is dependent on the type of medication under investigation, nature of the study and expected outcome measures. We recommend that all researchers using primary care databases be aware of the potential for missing prescribing data and be sensitive to how this can vary substantially between items, drug classes, patient groups and over time. Close liaison with practising primary care clinicians in the UK is often essential to ensure awareness of nuances in clinical practice.

Clozapine in the treatment of refractory schizophrenia: a practical guide for healthcare professionals

BACKGROUND

Clozapine remains the only medication licensed for treating refractory schizophrenia. However, it remains underutilized in part due to concerns regarding adverse events.

SOURCES OF DATA

Published literature.

AREAS OF AGREEMENT

Common adverse events during clozapine treatment include sedation, hypersalivation, postural hypotension, dysphagia, gastrointestinal hypomotility, weight gain, diabetes mellitus and dyslipidaemia. Rare but serious events include agranulocytosis, cardiomyopathy, myocarditis, pneumonia, paralytic ileus and seizure.

AREAS OF CONTROVERSY

It remains unclear how best to minimize clozapine-induced morbidity/mortality (i) during dose titration, (ii) from hypersalivation and (iii) from gastrointestinal hypomotility. It is also unclear how clozapine pharmacokinetics are affected by (i) gastrointestinal hypomotility, (ii) systemic infection and (iii) passive exposure to cigarette smoke. Whether monthly haematological monitoring needs to continue after 12 months of uninterrupted therapy is also a subject of debate.

GROWING POINTS

There is a need for better management of serious clozapine-related adverse events in addition to agranulocytosis. There is also a need for better education of patients and carers, general practitioners, A&E and ITU staff and others of the problems posed in using clozapine safely.

AREAS TIMELY FOR DEVELOPING RESEARCH

There is a need for more research on assessing clozapine dosage (i) as patients get older, (ii) with respect to exposure to cigarette smoke and (iii) optimizing response if adverse events or other factors limit dosage.

Stopping and switching antipsychotic drugs

In general, specialist advice should be sought when stopping or switching antipsychotics

While antipsychotics are often needed long term, there are circumstances when clinicians, patients and families should reconsider the benefits versus the harms of continuing treatment

Withdrawal syndromes, relapse and rebound can occur if antipsychotics are discontinued, especially if they are stopped abruptly. Generally, they should be reduced and stopped slowly, ideally over weeks to months

Relapse of psychosis and exacerbation occur in most patients with psychotic disorders, occasionally with drastic consequences. Sometimes this occurs many months after stopping antipsychotics

Switching from one antipsychotic to another is frequently indicated due to an inadequate treatment response or unacceptable adverse effects. It should be carried out cautiously and under close observation

When clozapine appears at a dance event…

Objectives: The content of substances sold and consumed as party drugs is often unknown. They may contain inactive, contaminated or unexpected ingredients, and the dosage of the active components may vary considerably. Obviously, these phenomena increase the chances of a wrong or delayed therapy. To illustrate this point, we report 3 cases of clozapine intoxication at a dance event where most likely clozapine tablets were sold as party drugs.Methods: The three cases were part of a prospective toxicology study at a nocturnal indoor dance event.Results: One patient had to be intubated after obstructive breathing with desaturation and bradycardia, while the 2 other patients presented with syncope and altered mental status. All patients recovered after 20 minutes to 8 hours. Systematic toxicological analysis of the blood samples revealed the presence of clozapine (73-244 ng/ml) and its metabolite norclozapine (9-59 ng/ml). A pill, found in a pocket of one patient, was identified as Leponex® 100 mg (clozapine). This neuroleptic drug is mainly prescribed for treatment-resistant schizophrenia. In clozapine-naive subjects, orthostatic hypotension, bradycardia and syncope have been reported with a single 25 mg oral dose. Serum clozapine concentrations of the 3 cases were below the defined therapeutic range (350-600ng/ml) and the clozapine:norclozapine ratios were suggestive for recent drug intake.Conclusion: Routine drug screening may be unable to detect the toxic agent(s) involved. Whenever unusual symptoms are observed in an intoxicated patient, blood and urine samples should be sent to a reference toxicology laboratory.

Clozapine-induced myocarditis: Follow-up for 3.5 years after successful retrial

Schizophrenia patients have significantly lower life expectancy than the general population. Clozapine is the most effective antipsychotic to reduce the mortality rate in these patients. Here, we report a schizophrenic patient with clozapine-induced myocarditis and successful retrial. In the first trial, clozapine was discontinued due to myocarditis. In the second trial, the titration rate was slower, and sodium valproate was not coadministered with clozapine. The patient has not developed myocarditis over 3.5 years of observation. It may be possible to take clozapine for a long time even after clozapine-induced myocarditis, and thus improve the life expectancy of schizophrenia patients.