# Each 5-mL portion of Maalox contains 400 mg of magnesium hydroxide, and 40 mg of simethicone. If the recommended dose is 2 teaspoons 4 times a day, how many grams of each substance would an individual take in a 24-hour period? (1 teaspoon= 5 mL)

Mar 3, 2015

Your patient would get 8 times more magnesium hydroxide and simethicone than a teaspoon contains.

So, you know that you have $\text{5-mL}$ portions of your drug to work with. The recommended dosage is two teaspoons, or two $\text{5-mL}$ doses, 4 times a day.Since a day has 24 hours, this will mean that your patient gets 2 teaspoons every 6 hours.

This means that, during a 24-hour period, your patient will get

$\text{24 hours" * "2 teaspoons"/"6 hours" = "8 teaspoons}$

Since a teaspoon holds $\text{5-mL}$ of your drug, the amounts of magnesium hydroxide and simethicone he'll get are

$\text{8 teaspoons" * "5 mL"/"1 teaspoon" * "400 mg"/"5 mL" = "3200 mg }$ $M g {\left(O H\right)}_{2}$

and

$\text{8 teaspoons" * "5 mL"/"1 teaspoon" * "40 mg"/"5 mL" = "320 mg simethicone}$

If you these values to one sig fig, the number of sig figs in 5 mL, 400 mg, and 40 mg, the answer will be

${m}_{M g {\left(O H\right)}_{2}} = \text{3000 mg }$ and

m_("simethicone") = "300 mg"

Since you must give the answer in grams, use a simple conversion factor to go from mg to g

$\text{3000 mg "Mg(OH)_2 * "1 g"/"1000 mg" = "3 g }$ $M g {\left(O H\right)}_{2}$

and

$\text{300 mg simethicone" * "1 g"/"1000 mg" = "0.3 g simethicone}$