• A survey of the prescribing of selective serotonin reuptake inhibitors by psychiatrists

      Lawton, John D.; Naik, Prakash (1995)
      Questionnaires were sent to 92 doctors asking them aspects of their antidepressant prescribing; 72 returned them. Sixty had prescribed selective serotonin reuptake inhibitors (SSRIs) in the previous year. The ratio of SSRIs to all antidepressants prescribed in the previous year exceeded 40% in only eight doctors. Inability to tolerate and failure to respond to established antidepressants were the most common indications for prescribing SSRIs. Side effects and cost were the most common reasons deterring doctors from prescribing SSRIs. SSRIs being new products and doubtS regarding their efficacy were factors that were significantly more likely to deter 'doctors of other grades' than consultants from prescribing them. Fluoxetine and paroxetine were the most frequently prescribed SSRIs.
    • Audit on clozapine dose and plasma level correlation for patients with chronic treatment-resistant psychosis

      Macnamara, Olivia; Lawton, John D.; Lankappa, Sudheer (2021)
      Aims Clozapine is associated with a risk of severe adverse events for which there are current monitoring systems are in place; however, there are no established regimens for monitoring of clozapine plasma levels. Recent Medicines and Healthcare products Regulatory Agency (MHRA) guidance advises clozapine levels should be monitored in certain clinical situations where toxicity may be suspected. This audit aimed to evaluate current practice of clozapine level monitoring within one Local Mental Health Team (LMHT). Method Electronic (RiO) records of 41 patients (33 male, 8 female; aged from 27 to 76 years; mean age 45 years) registered to the ZTAS system within the Nottingham City Central LMHT were reviewed. 46% had been on clozapine for over 16 years. 73.3% of patients were within clusters 12 and 13; 25.4% of patients were in cluster 11, with one patient in cluster 8. Dates of clozapine plasma level tests for each patient between 2006 and 2020 were found on the electronic NoTIS system, along with clozapine, norclozapine and total clozapine levels. Concurrent clozapine dose and regimens were obtained from pharmacy records from 2018 onwards. Result 273 clozapine plasma levels were conducted between 2006 and 2020. The average interval between levels taken was 10 months, 2 weeks but had a wide range, the shortest interval being 2 days, the longest being 13 years. 88 levels taken were >600 ug/L, suggesting increased toxicity risk. 108 levels were <350 ug/L, suggesting possible sub-optimal dosing or non-compliance. Statistical tests on correlation coefficient, although statistically non-significant (R = 0.37), showed a positive trend between total clozapine dose and the plasma level between all 3 parameters (i.e. clozapine, norclozapine and total clozapine). Conclusion There does not appear to be any routine plasma clozapine level monitoring throughout the LMHT with an average interval between tests of 10 months. There was a non-significant but positive trend between total daily dose of clozapine and clozapine level. 32% of clozapine levels returned were higher than the recommended level. We would recommend as suggested in the guidelines from MHRA, clozapine plasma levels should be monitored in certain clinical situations with increased toxicity risk. Trough levels should be taken with records of time of previous dose taken. Limitations of this study included a small sample size (41 patients) with data collection reliant on electronic systems. It was unclear if these results represent trough levels, making values difficult to interpret. Multifactorial impact on clozapine metabolism causes wide patient variability in plasma levels.