A nurse practitioner prepares an injection of promethazine, an antihistamine used to treat allergic rhinitis. If the stock bottle is labeled 25 mg/mL and the order is a dose of 11.0 mg, how many milliliters will the nurse draw up in the syringe?

The correct answer is 0.44ml

For information, promethazine is a neuroleptic antihistamine inhibitor of H1 receptors of the phenothiazine family. It is a medicine used in the treatment of allergy (like rhinitis) and transient insomnia.

To respond to this exercise, it is necessary to cross-multiply.

In the antihistamine bottle solution:

25 mg corresponds to 1 ml

11 mg corresponds to: 11/25 = 0.44 ml of the solution.

This 0.44ml is taken from the bottle and put to the syringe.