Options for Switching Antipsychotics

Medication cost, adverse effects, and poor therapeutic response often necessitate switching a hospice patient from one antipsychotic to another.  Prescribers can choose among several options when a switch is necessary.

Abrupt switch:

Often preferred by hospice prescribers, one antipsychotic can be abruptly discontinued with the immediate start of a new antipsychotic at a therapeutic dose.

Gradual tapering:

The initial antipsychotic dosage can be decreased by 25 to 50% of the total daily dose every 4 or 5 half-lives with concurrent up-titration of the new antipsychotic.  Refer to the chart of half-lives of common antipsychotics.

Overlap:

When overlapping products, the initial antipsychotic is continued at full dose while titrating the patient’s new antipsychotic.  When the new antipsychotic is at a therapeutic dose, the initial antipsychotic is tapered for discontinuation.

Since no one option is universally superior to another, prescribers must select the best switch method on a patient-by-patient basis.  Patient prognosis, patient stability, clinical status, efficacy of current medication(s), type of side effect(s) present, potential side effects of the new antipsychotic, and caregiver limitations are important factors that must be considered.

Problems occurring early after a switch can include psychotic symptoms, insomnia, anxiety, agitation, and extrapyramidal effects.  Since these effects can be either a response to the new medication or a result of withdrawal of the previous medication, they can be managed in various ways.  Watchful waiting is often preferred when symptoms are mild.  A slow restart of the initial antipsychotic may be necessary if severe rebound effects or withdrawal symptoms are present.  When the switch results in anxiety and restlessness, the addition of a benzodiazepine can provide temporary benefit of withdrawal effects, allowing clinicians to wait to see how the patient tolerates the switch once withdrawal dissipates.

Half-Lives of Common Antipsychotic Medications

Haloperidol 15-37 hours
Olanzapine 21-54 hours
Quetiapine 6 hours
Risperidone 3 hours in extensive metabolizers;20 hours in poor metabolizers
Ziprasidone 7 hours

 

References:

Martin, C. Reducing antipsychotic medications: developing a systematic process. Consult Pharm 2015;30:378-84.

Bobo, W. (2013, Mar 13). Switching anitpsychotics: why, when, and how? Psychiatric Times. Retrieved from http://www.psychiatrictimes.com

About the author

Origins Pharmacy Solutions

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

Copyright © 2014. Created by Meks. Powered by WordPress.