The provider has ordered 180 mg of Dilantin PO every 8 hours. The label of the drug reads 250 mg per 5 ml. How many milliliters will the nurse administer per dose?

Choice A reason: To calculate the dose, divide the ordered 180 mg by the concentration of 250 mg per 5 ml: (180 mg ÷ 250 mg) × 5 ml = 0.72 × 5 = 3.6 ml. This precise calculation ensures the correct amount of Dilantin is administered, matching the provider’s order. Choice B reason: A 4.5 ml dose would deliver 225 mg (4.5 ml × 250 mg/5 ml), exceeding the ordered 180 mg. This overdose could increase the risk of toxicity, as Dilantin has a narrow therapeutic range, making this an incorrect choice. Choice C reason: A 5 ml dose delivers 250 mg (5 ml × 250 mg/5 ml), significantly more than the ordered 180 mg. This excessive dose could lead to adverse effects like ataxia or nystagmus, rendering this choice incorrect for the prescribed amount. Choice D reason: A 7 ml dose would provide 350 mg (7 ml × 250 mg/5 ml), far exceeding the ordered 180 mg. Such a high dose could cause severe toxicity, including neurological symptoms, making this an inappropriate and unsafe choice.