A prescription reads phenytoin 0.2 g orally twice daily. The medication label states that each capsule is 100 mg. The nurse prepares how many capsule(s) to administer 1 dose?

Choice A reason: A dose of 0.2 g (200 mg) requires 2 capsules of 100 mg each, not 3. Administering 3 capsules would deliver 300 mg, exceeding the prescribed dose, potentially causing toxicity due to phenytoin’s narrow therapeutic index, making this choice incorrect. Choice B reason: “None of the above” is incorrect, as the calculation for 0.2 g (200 mg) divided by 100 mg per capsule yields exactly 2 capsules. A precise dose is possible with the available capsules, so this option does not apply to the scenario. Choice C reason: Converting 0.2 g to 200 mg and dividing by 100 mg per capsule results in 2 capsules per dose. This matches the prescription exactly, ensuring therapeutic levels of phenytoin, an anticonvulsant, are administered safely, making this the correct choice. Choice D reason: One 100 mg capsule provides only half the prescribed 0.2 g (200 mg) dose. This underdosing could lead to subtherapeutic phenytoin levels, risking seizures in a patient dependent on this anticonvulsant, making this choice incorrect.