What is the dosage for prochlorperazine?

The maximum safe dose of Phenergan (Promethazine) is as follows- Oral tablets 50 mg as a single dose every 12 hours Injection 50 mg IM , every 12 hours Reference British National Formulary-2008 This maximum dose is used under special circumstances. The dose commonly prescribed is Oral tablets 25 mg 12 hrly Injections 25 mg IM 12 hourly