Antipsychotic drugs may be used for schizophrenia as well as other disorders that may have psychotic features such as depression, bipolar disorder, schizophreniform disorder, schizoaffective disorder.

 

The drug that you choose depends on the side effects and the efficacy in an individual patient. 

-Clozapine is more effective for schizophrenia that is refractory. 

-Atypical antipsychotics (which act on both dopamine and serotonin receptors) may be more effective than the typical antipsychotics (act only on dopamine receptors).

 

With most antipsychotic drugs, you will need to start by giving divided doses (2-4 times per day) to prevent the initial dose-related side-effects. 

-Olanzapine (zyprexa) can be started with the initial dose (1 time per day). 

It will take about 5 days to reach steady state-- after which the patient can start taking the medication once per day.

-Ziprasidone will still need to be given in divided doses.

You can add benzodiazepines for patients that feel agitated.

 

Oral: for all antipsychotics

Intramuscular long acting (depot) types: Risperidone, Haldol, Prolixin

-Haldol: start very high (20x the daily Oral dose but given in divided doses of 3-4). Give this much every day for 1 week.   Maintenance dose: 200mg/30 days.

-Risperidol: start low (25 mg IM/ 2 wks)

-Prolixin: start low (25mg IM/ 2 wks)

Intramuscular short acting types: 

-Ziprasidone and Olanzapine given in doses of 10 mg / 2 hours

-Thorazine give in doses of 25-50 mg

-Haldol givein in doses of 10 mg.

IV:

-Haldol

 

-Low potency drugs will cause anticholinergic side effects (dry mouth, constipation, blurry vision, urinary retention), orthostatic hypotension, and drowsiness.

Examples: chlorpromazine, thioridazine, clozapine

-High portency drugs will cause extrapyramidal side-effects (dystonia, Parkinsonian syndrome, akathasia – restlessness)

Examples: Haloperidol, Fluphenazine

-All antipsychotics, except Clozapine, will produce tardive dyskinesia and can rarely cause neuroleptic malignant syndrome (NMS). However, Clozapine (and Olanzapine) can cause weight gain as well as type II diabetes.

-Atypical antipsychotics can cause type II diabetes (Olanzapine = Clozapine > Resperidone > Quatiapine)

-Thioridazine causes cardiac conduction delay (prolonged QT interval) and also retinitis pigmentosa (if given in doses over 800 mg/day). Ziprasidone may cause some prolonged QT but is usually insignificant.

-Chlorpromazine may cause cholestatic jaundice.