5 hours, 50% of the amount of
Singulair in your body will be eliminated. If you took a 5mg dose of
Singulair, within the time frames they gave, you will only have 2.5mg left in your body. 2.7-5.5 hours later, you will have 50% of THAT amount left in your body.This 50% reduction will continue until all of the medication is out of your system.
I totally suck at math but maybe YOU'RE an Einstein and can figure out, from this equation, exactly when the last of the Singulair will leave your body.