According to the Geodon Prescribing Info:
Schizoprenia: Initial dose should be 20mg twice daily taken with food. Dosage for some patients can be adjusted on the basis of individual status up to 80mg twice daily
BiPolar Disorder: Initial dose should be 40mg twice daily taken with food. Dose can be adjusted to up to 80mg twice daily if necessary.

Side effects can include feeling tired so it's best to check with the prescribing doctor about how to reduce this side effect.