Lasix (furosemide) is supposed to be used for the treatment of high blood pressure. Your doctor can also prescribe this medicine to treat fluid retention resulting from heart or liver disease. Depending on why you are required to take this drug your health care provider will prescribe you to take furosemide once a day (in the morning) or twice a day (in the morning and in the afternoon). If you skip your dose you can take it as soon as you remember unless it's almost time for a new dose. In that case just skip the dose you forgot about and go back to your normal dosing schedule.