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Furosemide, commonly known by its brand name “Lasix“, is a potent diuretic, often termed a “water pill”. This medication works by promoting the removal of excess fluid and salt from the body through urine. Typically prescribed to treat fluid retention (or edema) and high blood pressure, furosemide has become an essential tool in the arsenal of medical professionals managing cardiovascular conditions, liver disease, and certain kidney disorders.

Side Effects

While furosemide is undoubtedly beneficial for many, like all medications, it does come with its share of side effects. Common side effects include increased urination, dizziness, dehydration, and a feeling of lightheadedness. On the more serious side, the drug can sometimes lead to a depletion of potassium in the body, which can cause muscle cramps, palpitations, and fatigue. There are also rare but severe side effects to watch out for, such as hearing loss or allergic reactions.


Furosemide can interact with various medications, altering its effectiveness or amplifying potential side effects.

Some significant interactions to be aware of include:

Digoxin: Co-administration can increase the risk of digitalis toxicity.

Lithium: Lithium toxicity can be enhanced when taken with furosemide.

Anti-hypertensives: Concurrent use can further reduce blood pressure, sometimes to dangerous levels.

NSAIDs: Can reduce the diuretic effect of furosemide and increase kidney toxicity.

Always discuss any other medications, supplements, or over-the-counter drugs you’re taking with your healthcare provider.

Other Warnings

Prolonged use of furosemide can impact kidney function, making regular monitoring essential. Moreover, individuals with certain medical conditions, such as lupus, gout, or severe kidney disease, should approach furosemide with caution. This drug might exacerbate these conditions or decrease its efficacy. If you experience sudden weight gain, drastic changes in urine volume, or persistent nausea, consult your doctor immediately.

Dosage of Furosemide (Lasix)

When it comes to furosemide, the dosage can vary based on several factors including the condition being treated, the patient’s age, kidney function, and overall health status. As with all medications, it’s vital to adhere strictly to the prescribed dose.

For Fluid Retention (Edema):

Adults: The initial dose is usually 20 to 80 mg daily, which can be adjusted based on response. In resistant cases, this dose can be increased in intervals until the desired effect is achieved. Doses can range from a single dose every other day to, in extreme cases, doses exceeding 600 mg daily, although this is rare.

Children: The starting dose is typically 2 mg per kilogram (kg) of the child’s weight, taken as a single dose. If the response isn’t satisfactory, the doctor may increase the dose in increments, but not more than 6 mg per kg of the child’s weight.

For High Blood Pressure:

Adults: The typical starting dose is 40 mg twice a day. Depending on how the patient’s body responds to the medication, the doctor might adjust the dose.

Children: The dose is determined by the child’s weight and the medical condition being treated. The usual starting dose is 1 mg per kg weight, not exceeding 40 mg per day.

Available Dosages:

Furosemide is available in various dosage forms:

Tablets: They are available in 20 mg, 40 mg, and 80 mg strengths.

Oral solution: This is available in 8 mg/mL and 10 mg/mL concentrations.

Injectable form: Used in hospitals or for those who cannot take oral medication.

It’s crucial to understand that the exact dosage and frequency of administration should be determined by a healthcare provider. Overdosing can lead to severe dehydration, electrolyte imbalances, and other complications. Conversely, underdosing might not provide the therapeutic benefit desired.

Always take furosemide with a full glass of water and avoid taking more than your prescribed dose. If you miss a dose, take it as soon as you remember. However, if it’s near the time for your next dose, skip the missed dose and continue with your regular schedule. Don’t double up doses to make up for a missed one.

Regular Monitoring: Given the potential side effects and interactions, regular check-ups with your healthcare provider are crucial when on furosemide.

Diet: Consuming a balanced diet, particularly one rich in potassium, can help counteract some of the medication’s side effects.

Consistency: Take furosemide at the same time each day to maintain consistent levels in your system and to avoid nocturnal disruptions due to increased urination.

In conclusion, furosemide is a potent and beneficial medication for many individuals. Still, understanding its potential side effects, interactions, and other warnings ensures safe and effective use. Always work closely with a healthcare professional when using this or any medication.