Lasix Dosages for Kids and Adults: Your GoodRx Guide

Lasix (furosemide) is a popular prescription medication for high blood pressure (hypertension). It can also lessen swelling from fluid buildup (edema) from medical conditions like heart failure and kidney troubles. 

If you’re prescribed Lasix, it’s important that you understand how to take this diuretic (“water pill”) properly. After all, Lasix’s ability to get rid of excess fluid can help improve your quality of life. But being able to maximize its effectiveness with some simple tips and tricks gives it the best chance for success.

In this guide, we’ll review common and approved Lasix dosages. But keep in mind that your healthcare provider might recommend a different dosage for you. So it’s important to follow their specific instructions for taking Lasix.

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What’s the typical Lasix dosage for adults?

Lasix comes in multiple dosage forms, including an oral tablet and oral solution (liquid). The pills are available as 20 mg, 40 mg, and 80 mg oral tablets. The oral solution is available in 8 mg/mL and 10 mg/mL formulations.

Other versions of Lasix are also available. If you’re in the hospital, your healthcare provider may administer furosemide into your muscle (IM) or into your vein (IV). It’s also available as an injection that you can administer at home under the skin (Furoscix).

Regardless of formulation, Lasix dosages for adults can vary depending on what health condition you’re trying to treat. This guide focuses on the oral versions of furosemide.

High blood pressure

The typical Lasix dosage for high blood pressure is 80 mg, usually divided into two doses (40 mg twice a day). Your healthcare provider may adjust your dose until your blood pressure is at the desired goal, which can be different for each person. A target blood pressure for many people is 130/80 mmHg or less. But, keep in mind that Lasix is not usually a first-choice medication for treating high blood pressure.

Some people may need a lower dose of Lasix from the start. If you’re taking another blood pressure medication, such as losartan (Cozaar), your provider may start you on a lower 20 mg to 40 mg daily dose. They may also change the dosage of your other blood pressure medications. The effects of blood pressure medications can intensify when they’re taken together. Other interacting medications, like certain antibiotics, may also impact your dosage.

Your healthcare provider may also recommend lowering your Lasix dose if your blood pressure drops too low (hypotension) while taking Lasix. Possible symptoms of low blood pressure include dizziness, blurry vision, and confusion.

Swelling

For swelling caused by fluid buildup, a single 20 mg to 80 mg Lasix dose is initially recommended. This helps start the process of removing excess fluid, and your provider may have you repeat the same dose 6 to 8 hours later. They may then gradually increase your dose until the swelling goes down.

Your provider may also want you to take Lasix daily over time for fluid management. After your maintenance dose is determined by your healthcare provider, it should be taken once or twice a day. In milder cases, they may only want you to take it a few times a week instead of every day. The maximum recommended Lasix dosage is 600 mg a day, for severe cases of fluid buildup.

What’s the typical Lasix dosage for children?

Lasix is approved to treat swelling caused by certain medical conditions in young children and adolescents, too. The dosage for children is typically determined based on their body weight. 

The usual starting dosage of Lasix is 2 mg per kg body weight by mouth given as a single dose. For a child weighing 20 kg (44 lbs), this translates to a 40 mg dose. Your child’s provider may have your child repeat the same dose 6 to 8 hours later if the swelling doesn’t come down. The maximum dose is 6 mg per kilogram body weight.

If your child needs to take Lasix over time for fluid maintenance, the lowest effective dose should be used.

Are there any dosage adjustments for medical conditions?

Age is a main factor for Lasix dose adjustments. If you’re 65 years or older, your healthcare provider may recommend a lower starting dose. This is because older adults tend to be more sensitive to medications, including Lasix. Lasix side effects may be more likely to happen.

On the other hand, there’s no specific Lasix dosage adjustment for people with kidney or liver problems. In fact, Lasix is often recommended in people with kidney or liver problems. It can reduce swelling due to fluid buildup caused by these conditions.

What happens if you miss a dose of Lasix?

One or two missed doses shouldn’t be a big deal. If you forget to take your routine dose of Lasix, take it as soon as you remember. But if it’s close to the time of your next dose, skip the missed dose altogether. You can take the next dose at your regularly scheduled time. Don’t double your dose to make up for the missed one. 

If you find yourself frequently missing doses, talk to your healthcare provider or pharmacist. They can help you find a method that empowers you to take your doses more consistently, like a medication reminder app or a pill organizer.

What should you do if you take too much Lasix?

Taking too much Lasix raises the odds of side effects. This may include dizziness, low blood pressure, and headache. You may also have to urinate even more frequently (this often happens even with regular doses of Lasix). The severity of these side effects often depends on how much you took and when you took it. 

Even if your symptoms feel mild, you should check in with your healthcare provider. They can help you determine whether you can safely manage your side effects at home. If your symptoms feel more severe — including problems like sudden muscle cramps or numbness in your face, hands, or feet — your provider may want you seek immediate medical care. 

How to save on Lasix

There are many ways to save on Lasix, which is available as both a brand-name and generic medication. GoodRx can help you save over 70% off the average retail price of the generic version. Generic furosemide’s price at certain pharmacies is less than $1.80 with a free GoodRx discount.

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Written by:

Makaela Premont, PharmD

Makaela Premont, PharmD, is a pharmacist and the founder of uniquelymickie.com, a website dedicated to helping pharmacy students and pharmacists create a life that they enjoy. She received her Doctorate of Pharmacy from the University of South Carolina and is a licensed pharmacist in North Carolina.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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