If a prescription requires 250 mg of a drug and it is available in 100 mg tablets, how many tablets are needed?

To determine how many 100 mg tablets are needed to achieve a total of 250 mg, you start by dividing the total required dosage by the amount each tablet contains. In this case, you take the 250 mg and divide it by 100 mg per tablet.

250 mg ÷ 100 mg/tablet = 2.5 tablets.

Since you cannot dispense half a tablet in this scenario, you round up to the nearest whole number, which is 3 tablets. However, considering that the prescription specifically requires 250 mg—and that 3 tablets provide 300 mg—it can indicate the dispensing of additional product to give the exact amount required might be the solution.

In a real-world setting, if the dosing required explicitly lists 250 mg, then a pharmacy would discuss whether to adjust the formulation or choice of tablet to meet the exact need without excess. This is why you would determine that's not simply about rounding up but also about meeting that exact medicine requirement in practice.

Thus, the correct answer reflects a simple calculation but also speaks to the practice of precise drug dispensation. The answer directly helps in an understanding of how to handle medication dosages while appreciating the nuances involved in real-world pharmacy practices.