A nurse is preparing to administer promethazine 25 mg IM to a client. Available is promethazine 50 mg/mL. How many mL should the nurse administer? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)

Determine the total dosage: The client is prescribed 25 mg of promethazine. Calculate the volume per dose: The promethazine solution contains 50 mg per mL. The nurse needs to administer 25 mg per dose. To find the volume per dose: 50 mg / 1 mL = 25 mg / x mL 50x = 25 Dividing both sides by 50, we get: x = 0.5 mL