An adult client is prescribed streptomycin IM 1 g per day. Each mL contains 500 mg. How many milliliters should be administered?

An adult client is prescribed streptomycin IM 1 g per day. Each mL contains 500 mg. How many milliliters should be administered?

• A. 1 mL
• B. 2 mL
• C. 3 mL
• D. 4 mL

Answer: (B)

When you have a prescribed dose and a solution’s concentration, you convert the dose to the same units as the concentration and then divide to find the volume to administer. Here, the dose is 1 g, which equals 1000 mg. The solution is 500 mg per milliliter, so the volume needed is 1000 mg ÷ 500 mg/mL = 2 mL. Therefore, administer 2 mL to deliver the prescribed 1 g. If you gave 1 mL, you’d be delivering 500 mg—half the dose. If you gave 3 mL, you’d be delivering 1500 mg, and 4 mL would be 2000 mg. In this case, 2 mL matches the required 1 g.

When you have a prescribed dose and a solution’s concentration, you convert the dose to the same units as the concentration and then divide to find the volume to administer. Here, the dose is 1 g, which equals 1000 mg. The solution is 500 mg per milliliter, so the volume needed is 1000 mg ÷ 500 mg/mL = 2 mL. Therefore, administer 2 mL to deliver the prescribed 1 g.

If you gave 1 mL, you’d be delivering 500 mg—half the dose. If you gave 3 mL, you’d be delivering 1500 mg, and 4 mL would be 2000 mg. In this case, 2 mL matches the required 1 g.