Clozapine therapeutic drug monitoring – experience from a large London NHS trust

Abstract Introduction Clozapine is a high-risk drug that used widely in Secondary and Tertiary Centres.1 Therapeutic Drug Monitoring (TDM) advice recommendation readily available from distinguished authors.2,3 The rate of clozapine TDM, appropriate sample collection for actions following level varies between services prescribers within our organisation. Aim To establish how many current West London NHS Trust (WLT) patients had plasma samples collected TDM were done appropriately, the proportion with an appropriately result largely accepted therapeutic range, whether there was documentation reviewed if any prescription changes made. Methods Approval to undertake service evaluation given by clinical governance audit committee as ethical review not required. No patient identifiable details shared or collected. All who been registered on Trusts monitoring over 8 weeks enrolled. Anonymised demographic data including concomitant medication. Plasma levels sought every appropriateness taken scrutinised. Electronic notes also scrutinised assess result. Data binary yes/no format results calculated percentage. stored accordance General Protection Regulation (GDPR). Results In total 316 included. 97% these evidence during time audit. 88% patients’ correctly. Only 45% acceptable range. Of those whose fell outside range less than half (42%) reviewed. Discussion/Conclusion It when accurately can be vital source information inform dose, concordance toxicity therapy. Our showed routine TDM. There some variation but what most alarming lack action general Standardising needs priority continue carried out almost 100% population. References 1. Taylor DM, Barnes TRE, Young AH. Maudsley Prescribing Guidelines Psychiatry 14th Edition. Wiley Blackwell. 2. DM et al. use optimising Psych Bull 1995:19:753-755 3. Perry PJ. antipsychotics. Psychopharmacology 200; 148:83-89