A doctor prescribes diazepam IV at a dose of 7.5 mg to a patient. The available diazepam solution is 5 mg/mL. How many mL should the nurse prepare for administration?

To calculate the volume of medication to be administered, the nurse should use the standard dosage formula: (Desired Dose / Have Dose) x Volume = Amount to Administer. In this clinical scenario, the prescribed amount (Desired) is 7.5 mg, and the concentration on hand (Have) is 5 mg per 1 mL. Calculation: Formula: (7.5 mg / 5 mg) x 1 mL = X Step 1: 7.5 divided by 5 equals 1.5. Step 2: 1.5 multiplied by 1 mL equals 1.5 mL. The nurse must accurately draw up 1.5 mL of the diazepam solution into the syringe to provide the exact 7.5 mg dose ordered by the physician. Choice A reason: This is the mathematically correct volume derived from dividing the prescribed 7.5 mg by the concentration of 5 mg/mL. Accurate calculation is vital in intravenous administration to ensure therapeutic efficacy while avoiding the respiratory depression associated with benzodiazepine toxicity. Choice B reason: A volume of 0.5 mL would only provide 2.5 mg of diazepam (0.5 mL x 5 mg/mL). This is an under-dose of the prescribed 7.5 mg, which would likely fail to produce the necessary pharmacological effect for the patient's condition. Choice C reason: A volume of 1.0 mL would provide exactly 5 mg of diazepam. This does not meet the provider's order of 7.5 mg, resulting in a sub-therapeutic dose that could compromise the management of acute anxiety or seizure activity. Choice D reason: A volume of 2.5 mL would provide 12.5 mg of diazepam (2.5 mL x 5 mg/mL). This constitutes a significant medication error and overdose, increasing the risk of severe central nervous system depression, hypotension, and potential respiratory arrest.