Frusemide or Furosemide, a diuretic, is rapid acting and should be cleared within 15-24 hrs under normal physiologic conditions. However, please refer to the following resources for more precise information

Academic: Medications (http://www.ohsu.edu/academic/picu/Medications.htm) then enter name of drug

Pharmaceutical mfg: Furosemide 20mg/2ml Injectable Ampoule, Injectable solutions (http://www.lavoisier.com/en/products/drugs/injectable-solutions/furosemide-ampoule_48_0-0-1.html)

Federal Drug Admin: http://www.fda.gov/drugs/drugsafety/postmarketdrugsafetyinformationforpatientsandprovi ders/ucm111085.htm then search drug by name.

Independent web resources:
1) Complete Furosemide information from Drugs.com (http://www.drugs.com/ppa/furosemide.html)
2) Lasix (Furosemide) Drug Information: User Reviews, Side Effects, Drug Interactions and Dosage at RxList (http://www.rxlist.com/lasix-drug.htm)

Should you need further clarification (medical terminology, etc) in relation to the above resources please let us know.

You are always wise to check on your prescribed medications and I congratulate you for doing so.