The healthcare provider prescribes streptomycin 200 mg intramuscularly every 12 hours. The vial is labeled, “Streptomycin 1 gram/2.5 mL.” How many milliliters should the nurse administer? (Enter numerical value only. If rounding is required, round to the nearest tenth.)
The Correct Answer and Explanation is:
To determine the volume of streptomycin to administer, follow these steps:
- Understand the Concentration: The vial is labeled “Streptomycin 1 gram/2.5 mL,” which means that 1 gram (1000 mg) of streptomycin is dissolved in 2.5 mL of solution.
- Determine the Dose Required: The healthcare provider prescribes 200 mg of streptomycin.
- Calculate the Volume to Administer:
- Use the concentration provided to set up a proportion to find out how many milliliters contain 200 mg of streptomycin.
- Set up the proportion as follows:Volume to administer=(Desired DoseConcentration)×Volume of Solution\text{Volume to administer} = \left(\frac{\text{Desired Dose}}{\text{Concentration}}\right) \times \text{Volume of Solution}Volume to administer=(ConcentrationDesired Dose)×Volume of Solution
- Here, the concentration is 1 gram (1000 mg) in 2.5 mL. Thus,Volume to administer=(200 mg1000 mg)×2.5 mL\text{Volume to administer} = \left(\frac{200 \text{ mg}}{1000 \text{ mg}}\right) \times 2.5 \text{ mL}Volume to administer=(1000 mg200 mg)×2.5 mL
- Perform the Calculation:Volume to administer=(2001000)×2.5\text{Volume to administer} = \left(\frac{200}{1000}\right) \times 2.5Volume to administer=(1000200)×2.5 Volume to administer=0.2×2.5\text{Volume to administer} = 0.2 \times 2.5Volume to administer=0.2×2.5 Volume to administer=0.5 mL\text{Volume to administer} = 0.5 \text{ mL}Volume to administer=0.5 mL
Therefore, the nurse should administer 0.5 mL of streptomycin.
Explanation:
This calculation involves understanding drug concentrations and doses. First, we converted the concentration given (1 gram in 2.5 mL) into a form that aligns with the dose required (200 mg). By using a proportion, we accurately determined how much of the solution would contain the correct amount of drug. This ensures that the patient receives the precise dosage needed while maintaining safety and efficacy in medication administration. Always double-check calculations and confirm the correct medication and dosage to prevent errors in drug delivery.