A nurse is preparing to administer isoniazid 187 mg IM. Available is isoniazid injection 100 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.)

Desired dose = 187 mg. Available concentration = 100 mg/mL. Calculate the volume to administer in milliliters (mL). Volume to administer (mL) = Desired dose (mg) / Available concentration (mg/mL) = 187 mg / 100 mg/mL = 1.87 mL. Round to the nearest tenth = 1.9 mL.