The physician ordered 0.4 ml of potassium iodide (iostate) expectorant. the label reads 325 mg/tsp. how many milligrams are contained in this dose?

One teaspoon is equivalent to 4.92892 milliliters which is very close to 5 milliliter. So the steps in looking for the milligrams contained, first divide the 325 milligrams to the 1 teaspoon then multiplying it to 1 teaspoon divided by 5 milliliters then multiplying that to the 0.4 milliliter of potassium iodide.

Milligrams contained = (325 mg / 1 tsp) x (1 tsp / 5 mL) x 0.4 mL = 26 milligrams.