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Switching Antipsychotics

To see the consequences of a switch between antipsychotics click in the crosstable below: the switch is made "from" (vertical) "to" (horizontal).
During switching: don't reduce anticholinergics and adding oxazepam might be useful.

 from to → Am Ar Ch Cp Hp Ol Pi Qu Rd Sd Sr Zi RA Df Di Dh Do Dp Dr Dz Mz
Am Amisulpride  — AmAr AmCh AmCp AmHp AmOl AmPi AmQu AmRd AmSd AmSr AmZi AmRA AmDf AmDi AmDh AmDo AmDp AmDr AmDz AmMz
Ar Aripiprazole ArAm  — ArCh ArCp ArHp ArOl ArPi ArQu ArRd ArSd ArSr ArZi ArRA ArDf ArDi ArDh ArDo ArDp ArDr ArDz ArMz
Ch Chlorpromazine ChAm ChAr  — ChCp ChHp ChOl ChPi ChQu ChRd ChSd ChSr ChZi ChRA ChDf ChDi ChDh ChDo ChDp ChDr ChDz ChMz
Cp Clozapine CpAm CpAr CpCh  — CpHp CpOl CpPi CpQu CpRd CpSd CpSr CpZi CpRA CpDf CpDi CpDh CpDo CpDp CpDr CpDz CpMz
Hp Haloperidol HpAm HpAr HpCh HpCp  — HpOl HpPi HpQu HpRd HpSd HpSr HpZi HpRA HpDf HpDi HpDh HpDo HpDp HpDr HpDz HpMz
Ol Olanzapine OlAm OlAr OlCh OlCp OlHp  — OlPi OlQu OlRd OlSd OlSr OlZi OlRA OlDf OlDi OlDh OlDo OlDp OlDr OlDz OlMz
Pi Pimozide PiAm PiAr PiCh PiCp PiHp PiOl  — PiQu PiRd PiSd PiSr PiZi PiRA PiDf PiDi PiDh PiDo PiDp PiDr PiDz PiMz
Qu Quetiapine QuAm QuAr QuCh QuCp QuHp QuOl QuPi  — QuRd QuSd QuSr QuZi QuRA QuDf QuDi QuDh QuDo QuDp QuDr QuDz QuMz
Rd Risperidone RdAm RdAr RdCh RdCp RdHp RdOl RdPi RdQu  — RdSd RdSr RdZi RdRA RdDf RdDi RdDh RdDo RdDp RdDr RdDz RdMz
Sd Sertindole SdAm SdAr SdCh SdCp SdHp SdOl SdPi SdQu SdRd  — SdSr SdZi SdRA SdDf SdDi SdDh SdDo SdDp SdDr SdDz SdMz
Sr Sulpiride SrAm SrAr SrCh SrCp SrHp SrOl SrPi SrQu SrRd SrSd  — SrZi SrRA SrDf SrDi SrDh SrDo SrDp SrDr SrDz SrMz
Zi Ziprasidone ZiAm ZiAr ZiCh ZiCp ZiHp ZiOl ZiPi ZiQu ZiRd ZiSd ZiSr  — ZiRA ZiDf ZiDi ZiDh ZiDo ZiDp ZiDr ZiDz ZiMz
Df Fluphenazine_LA DfAm DfAr DfCh DfCp DfHp DfOl DfPi DfQu DfRd DfSd DfSr DfZi DfRA  — DfDi DfDh DfDo DfDp DfDr DfDz DfMz
Di Flupenthixol_LA DiAm DiAr DiCh DiCp DiHp DiOl DiPi DiQu DiRd DiSd DiSr DiZi DiRA DiDf  — DiDh DiDo DiDp DiDr DiDz DiMz
Dh Haloperidol_LA DhAm DhAr DhCh DhCp DhHp DhOl DhPi DhQu DhRd DhSd DhSr DhZi DhRA DhDf DhDi  — DhDo DhDp DhDr DhDz DhMz
Do Olanzapine_LA DoAm DoAr DoCh DoCp DoHp DoOl DoPi DoQu DoRd DoSd DoSr DoZi DoRA DoDf DoDi DoDh  — DoDp DoDr DoDz DoMz
Dp Paliperidone_LA DpAm DpAr DpCh DpCp DpHp DpOl DpPi DpQu DpRd DpSd DpSr DpZi DpRA DpDf DpDi DpDh DpDo  — DpDr DpDz DpMz
Dr Risperidone_LA DrAm DrAr DrCh DrCp DrHp DrOl DrPi DrQu DrRd DrSd DrSr DrZi DrRA DrDf DrDi DrDh DrDo DrDp  — DrDz DrMz
Dz Zuclopenthixol_LA DzAm DzAr DzCh DzCp DzHp DzOl DzPi DzQu DzRd DzSd DzSr DzZi DzRA DzDf DzDi DzDh DzDo DzDp DzDr  — DzMz
Mz Zuclopenthixol MA MzAm MzAr MzCh MzCp MzHp MzOl MzPi MzQu MzRd MzSd MzSr MzZi MzRA MzDf MzDi MzDh MzDo MzDp MzDr MzDz  —

LA = long acting, MA = medium acting
Rest AP = Chlorprothixene, Flupentixol, Loxapine, Paliperidone, Pericyazine, Perphenazine,Promazine, Trifluoperazine, Zuclopentixol.

General consideration

1. The goal of this switching table is to offer a guide for physician and pharmacist in switching antipsychotics. The table should be clear, easy to use and contain the most important information. Therefore, the table only contains the most common or special antipsychotics. There is also a group ‘rest AP’, containing antipsychotics with the same switching advice.

2. It should be noted that the table only contains a general advice.

3. Because of the risk of acute withdrawal symptoms (e.g. cholinergic rebound) and the risk of relapse, all antipsychotics are gradually tapered.

4. The standard tapering period is approximately two weeks. The two drugs are cross-tapered, reducing and increasing the dose with approximately 25% every 2-3 days.

5. To keep the content simple, dosages are given as percentages as much as possible. Dosages should be rounded to whole or half tablets.

6. All antipsychotics are categorized in short, medium and long, based on their half-life. Depot preparations are categorized as long. It takes approximately 3-5 times the half-life for a drug to reach steady state plasma levels or to be completely eliminated. Switching two antipsychotics with approximately the same half-life are not expected to generate obvious problems. Also switching from a drug with a long half-life to a shorter half-life is in general not expected to give problems, because the new drug will reach steady state plasma levels more quickly.

7. Switching from a drug with a short half life to a drug with a long half life is possibly more problematic. Plasma levels of the first drug decrease rapidly, while the second drug takes longer to reach a steady state plasma level. To overcome possible withdrawal/ relapse, the second drug should be started in a higher dose (approx. 50% of target dose) for about 4 days. Subsequently increase with 25% every 3-4 days.

8. Warnings and advice are limited to the switch only. Specific drug properties can be found via the links on the right.

9. Cytochrome P450 drug interactions between different antipsychotics are checked with the Flockart interaction table. No inductors or inhibitors were found.

10. Nearly all antipsychotics increase the risk of QT time prolongation with or without Torsade de Pointes (TDP). Under the heading ‘more information’ there is a recommendation, advising ECG monitoring. The SPC of sertindole contains the warning ECG monitoring required. No distinction has been made between drugs with and without TDP.