Lasix

Lasix is a medication that is prescribed for the treatment of high blood pressure and fluid retention. The medication is classified as a diuretic that works by increasing the amount of salt and water that the kidneys remove from the blood, which causes a decrease in blood volume. Lasix comes in the form of a tablet that is usually taken once or twice a day. Potential side effects of the medication may include low blood potassium levels, dizziness, upset stomach, and sensitivity to the sun.

What Is Lasix?

Lasix® (furosemide) is a prescription medicine that is used as a diuretic for high blood pressure and fluid retention. It is part of a class of medicines known as diuretics.
 

Who Makes It?

The brand-name drug is made by Hoechst Roussel Pharmaceuticals. Generic Lasix is made by several manufacturers.
 

What Is It Used For?

Specific uses of Lasix include:
 
(Click Lasix Uses for more information on what the medication is used for, including possible off-label uses.)
 

How Does Lasix Work?

Lasix is a diuretic, which is commonly referred to as a "water pill.
 " Specifically, it is known as a "loop diuretic," named after the part of the kidneys that it affects (the loop of Henle). It works by increasing the amount of salt and water the kidneys remove from the blood. This extra salt and water is passed out through the urine. By increasing the amount of water removed from the blood, Lasix causes a decrease in blood volume. Because of this effect, the medication can lower blood pressure and can also help with water retention.
 

When and How to Take Lasix

Some general considerations for when and how to take it include:
 
  • Lasix comes in tablet form. It is usually taken by mouth once or twice a day, although it may be taken several times a day in certain circumstances.
     
  • You can take it with or without food.
     
  • Lasix should be taken at the same time(s) each day to maintain an even level of the medicine in your blood. However, some people do not need to take it every day, especially people taking it for fluid retention.
     
  • Because it increases urination, it's best to take it in the morning (to avoid needing to get up to use the bathroom throughout the night). If you take it multiple times per day, it's best to take the last dose of the day before 6 p.m. (unless you are instructed otherwise).
     
  • For it to work properly, you must take it as prescribed. It will not work if you stop taking it.
     

Dosing Information

The dose that your healthcare provider recommends will vary depending on a number of factors, including:
 
  • Other medical conditions you may have
  • Other medications you may currently be taking
  • How you respond to Lasix.
     
As with any medication, do not adjust your dose unless your healthcare provider specifically instructs you to do so.
 
(Click Lasix Dosage for more information.)
 

Side Effects

As with any medicine, there are possible side effects. However, not everyone who takes it will experience side effects. In fact, most people tolerate the medication well. When side effects do occur, in most cases they are minor and either require no treatment or can easily be treated by you or your healthcare provider. Serious side effects are less common.
 
A few of the possible side effects of Lasix include:
 
  • Low blood potassium levels (hypokalemia) or other electrolyte imbalances
  • Dizziness
  • Upset stomach (nausea) or vomiting
  • Sensitivity to the sun.
     
(Click Lasix Side Effects to learn about specific side effects of the drug, including some of the more serious side effects that you should report to your healthcare provider.)
 

Drug Interactions

Lasix can potentially interact with a number of medicines.
 
(Click Lasix Drug Interactions for more information.)
 

What Should I Tell My Healthcare Provider Before Taking It?

You should talk with your healthcare provider prior to taking Lasix if you have:
 
  • Liver disease, including cirrhosis
  • Kidney disease or kidney failure
  • Diabetes
  • Systemic lupus erythematosus (lupus or SLE)
  • Gout
  • Fluid or electrolyte problems
  • Any allergies, including allergies to sulfa drugs, foods, dyes, or preservatives.
     
Also, let your healthcare provider know if you:
 
Tell your healthcare provider about all of the medicines you are currently taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
 
(Click Lasix Warnings and Precautions for more information on this topic, including information on who should not take this medication.)
 

Overdose With Lasix

People who take too much Lasix may have overdose symptoms that could include:
 
  • Dehydration
  • Low blood pressure (hypotension)
  • Low electrolytes (especially low potassium, chloride, and sodium).
     
If you happen to overdose, seek medical attention immediately.
 
(Click Lasix Overdose for more information.)
 

Storage Methods

It should be stored at room temperature, away from moisture and heat. Lasix tablets should be kept in an airtight container.
 
Keep this medication and all medications out of the reach of children.
 

What Should I Do If I Miss a Dose?

If you do not take your dose as scheduled, take your missed dose as soon as you remember. If it is almost time for your next scheduled dose, skip the missed one and continue with normal dosing. Do not take a double dose of Lasix.
 

Strengths of Lasix

Lasix is available in the following strengths:
 
A liquid version of generic Lasix is also available in the following strengths:
 
  • Furosemide 10 mg per 5 mL (10 mg per teaspoonful)
  • Furosemide 40 mg per 5 mL (40 mg per teaspoonful).
     
Injectable generic Lasix is also available for use in hospitals.
 

Generic Lasix

Both brand-name and generic Lasix tablets are currently licensed for sale. Generic (but not brand-name) Lasix solution is also available.
 
(Click Generic Lasix for more information.)
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;
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