Editing Clozapine (section)

==== Clozapine rechallenge ====
A clozapine "rechallenge" is when someone that experienced agranulocytosis while taking clozapine starts taking the medication again. In countries in which the neutrophil thresholds are higher than those used in the US a simple approach is, if the lowest ANC had been above the US cut off, to reintroduce clozapine but with the US monitoring regime. This has been demonstrated in a large cohort of patients in a hospital in London in which it was found that of 115 patients who had had clozapine stopped according to the US criteria only 7 would have had clozapine stopped if the US cut offs had been used. Of these 62 were rechallenged, 59 continued to use clozapine without difficulty and only 1 had a fall in neutrophils below the US cut off.<ref name="There Is Life After the UK Clozapin" /> Other approaches have included the use of other drugs to support neutrophil counts including [[Lithium (medication)|lithium]] or [[granulocyte colony-stimulating factor]] (G-CSF). However, if agranulocytosis still occurs during a rechallenge, the alternative options are limited.<ref name="Myles">{{cite journal | vauthors = Myles N, Myles H, Clark SR, Bird R, Siskind D | title = Use of granulocyte-colony stimulating factor to prevent recurrent clozapine-induced neutropenia on drug rechallenge: A systematic review of the literature and clinical recommendations | journal = The Australian and New Zealand Journal of Psychiatry | volume = 51 | issue = 10 | pages = 980–989 | date = October 2017 | pmid = 28747065 | doi = 10.1177/0004867417720516 | doi-access = free }}</ref><ref name="LallyJ">{{cite journal | vauthors = Lally J, Malik S, Krivoy A, Whiskey E, Taylor DM, Gaughran FP, Flanagan RJ, Mijovic A, MacCabe JH | title = The Use of Granulocyte Colony-Stimulating Factor in Clozapine Rechallenge: A Systematic Review | journal = Journal of Clinical Psychopharmacology | volume = 37 | issue = 5 | pages = 600–604 | date = October 2017 | pmid = 28817489 | doi = 10.1097/JCP.0000000000000767 | s2cid = 41269943 | url = https://kclpure.kcl.ac.uk/portal/en/publications/the-use-of-granulocyte-colonystimulating-factor-in-clozapine-rechallenge(123168da-3735-4007-886f-6087bef72040).html | access-date = 22 September 2021 | archive-date = 14 May 2023 | archive-url = https://web.archive.org/web/20230514220903/https://kclpure.kcl.ac.uk/portal/en/publications/the-use-of-granulocyte-colonystimulating-factor-in-clozapine-rechallenge(123168da-3735-4007-886f-6087bef72040).html | url-status = dead }}</ref><ref>{{cite journal | vauthors = Silva E, Higgins M, Hammer B, Stephenson P | title = Clozapine re-challenge and initiation following neutropenia: a review and case series of 14 patients in a high-secure forensic hospital | journal = Therapeutic Advances in Psychopharmacology | volume = 11 | pages = 20451253211015070 | date = January 2021 | pmid = 34221348 | doi = 10.1177/20451253211015070 | pmc = 8221694 }}</ref><ref>{{cite journal | vauthors = Silva E, Higgins M, Hammer B, Stephenson P | title = Clozapine rechallenge and initiation despite neutropenia- a practical, step-by-step guide | journal = BMC Psychiatry | volume = 20 | issue = 1 | pages = 279 | date = June 2020 | pmid = 32503471 | doi = 10.1186/s12888-020-02592-2 | doi-access = free | pmc = 7275543 }}</ref>