7 Bumex Side Effects to Know About
Key takeaways:
Bumex (bumetanide) is a loop diuretic. It treats edema (fluid buildup) due to heart failure, kidney disease, and liver disease. Though it’s usually well tolerated, Bumex side effects are possible.
Bumex can cause dehydration and electrolyte imbalances, such as low potassium, calcium, and magnesium. Side effects, like muscle cramps, dizziness, and low blood pressure, may occur as a result.
More rarely, Bumex can cause severe dehydration and electrolyte changes that lead to heart problems and seizures. That’s why your prescriber will monitor electrolyte levels before and during treatment.
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Bumex (bumetanide) is a brand-name prescription medication that’s FDA approved to treat edema (fluid buildup) due to heart failure, liver disease, and kidney disease. It belongs to the group of medications called loop diuretics. They’re a type of “water pill” that works in your kidneys to remove extra water and salt from your body.
Sometimes, Bumex and other loop diuretics may cause you to lose too much water, salt, or other electrolytes. This is often the cause of Bumex side effects.
Bumex comes as a tablet that you take by mouth. It’s also available as an injection healthcare professional can inject into your vein or muscle. This article will focus only on the oral form.
Bumex side effects at a glance
Most Bumex side effects are mild and go away as your body adjusts to the medication. It’s also possible to experience serious side effects, but it’s rare.
Mild Bumex side effects include:
Electrolyte changes, such as low potassium or magnesium
Low blood pressure
Dizziness
Muscle cramps
Headache
Nausea and vomiting
Dry mouth
Itching
Rare but serious Bumex side effects include:
Serious skin reactions
Hearing loss
Low platelet levels
Brain dysfunction in people who have liver damage (hepatic encephalopathy)
This medication also has a boxed warning — the FDA’s strictest medication warning — for severe dehydration and electrolyte loss if Bumex is taken in high doses. If needed, your prescriber will adjust your Bumex dose to prevent or manage water and electrolyte levels.
Let’s dive into seven Bumex side effects you may want to know about.
1. Muscle cramps
Muscle cramps are one of the most commonly reported Bumex side effects. This may occur due to volume loss and electrolyte imbalances, like low levels of potassium or magnesium (more on that below), that occur with loop diuretics. However, the research isn’t clear on whether diuretics truly cause muscle cramps, or if cramps are caused by something else.
Regardless, let your healthcare professional know if you have muscle cramps while taking Bumex. They may ask how much water you’re drinking to ensure you’re hydrated, since cramping can occur with dehydration — especially at night or after exercise. They may also discuss stretches you can do to improve cramping.
Additionally, your prescriber may check your blood potassium levels, among other electrolytes. If your levels are too low, they may recommend a potassium supplement or a magnesium supplement to take with Bumex.
2. Low electrolyte levels
Bumex causes water loss. With this comes electrolyte loss as well. Bumex can cause low levels of:
Potassium (hypokalemia)
Magnesium (hypomagnesemia)
Calcium (hypocalcemia)
Sodium (hyponatremia)
Chloride (hypochloremia)
Possible symptoms of almost all these electrolyte imbalances are muscle cramping or twitching, fatigue, and dizziness. But you may not experience any symptoms unless levels are very low. More serious risks include heart problems, such as abnormal heart rhythm (arrhythmia) and seizures.
Make sure your prescriber knows your full health history, and has your complete medication list, before starting Bumex. Certain health conditions and medications can make electrolyte imbalances more likely (or more risky if they occur).
Before and during Bumex treatment, your prescriber will check your electrolyte levels. They may recommend supplements if they’re too low. Or they might recommend adding a potassium sparing diuretic. Unlike Bumex, these diuretics can increase potassium and magnesium levels in the blood.
3. Dizziness and low blood pressure
Dizziness and low blood pressure (hypotension) can occur with Bumex, though it may go away as your body gets used to the medication.
Since Bumex helps your body get rid of extra fluid, your blood pressure may decrease and cause dizziness as a result. If you had high blood pressure before taking Bumex, this may be a good thing. But if your blood pressure gets too low, fainting, falls, and injuries could occur. This Bumex side effect can be especially concerning for older adults, who are at greater risk of long-term problems from falls.
Before starting Bumex, ask your prescriber if you should be checking your blood pressure at home. This helps you notice if your blood pressure drops too low. If you are checking your blood pressure and it’s lower than usual, let your prescriber know.
To prevent falls, hold onto something when you move from a sitting to standing position. You should also sit down anytime you experience dizziness. Keep your house free of trip hazards as well.
If dizziness continues, let your prescriber know. They may check your electrolytes, lower your Bumex dosage or adjust your doses of other blood pressure medications, if you take them.
4. Headache
Another possible Bumex side effect is headache. Like dizziness, headaches may go away as your body gets used to Bumex.
Headaches from Bumex may be due to dehydration. So make sure you’re drinking enough water while taking the medication. Check with your prescriber about how much water you should drink, since some people taking diuretics are required to restrict their fluid intake.
Headaches could also be a sign of an electrolyte imbalance. So if you’re experiencing headaches frequently, your prescriber may check your electrolyte levels.
Keep in mind that headaches can be due to several causes. In some cases, an over-the-counter pain reliever like ibuprofen (Advil, Motrin) or acetaminophen (Tylenol) can help. But it’s a good idea to check with your prescriber first, as some people may need to avoid these medications if they have certain health conditions.
5. Nausea
Some people may experience nausea or vomiting while taking Bumex, though it’s not common. If you do experience nausea, it’s likely to be mild. But in rare cases, nausea and vomiting may also be symptoms of electrolyte imbalances, such as hypokalemia.
Let your healthcare professional know if you have nausea that doesn’t stop or leads to vomiting while taking Bumex. They can do a blood test to check for any electrolyte imbalances.
Keep in mind that vomiting can lead to dehydration. For this reason, it’s important to stay hydrated and drink fluids you can tolerate if you have nausea or vomiting. However, talk with your healthcare professional if you’re having trouble keeping fluids down. They can help you know how to keep your fluid intake balanced while taking Bumex.
6. Serious skin reactions
In rare cases, Bumex can cause serious skin reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).
SJS and TEN are both serious and potentially life-threatening reactions to a medication. They may start with flu-like symptoms, such as fever, sore throat, or cough. But after a few days, you may develop a rash that progressively worsens, leading to blistering, peeling skin.
SJS and TEN are medical emergencies. If you develop a rash while taking Bumex, stop taking it and contact your prescriber immediately. If it’s severe, or accompanied by a fever, seek emergency care.
7. Severe dehydration
As mentioned before, Bumex works by helping your body get rid of extra fluids. Mild dehydration may happen with Bumex. But in rare cases, severe dehydration can occur. Severe dehydration is more likely if you take too much Bumex or don’t stay hydrated while taking it.
Symptoms of dehydration can include:
Dizziness
Tiredness
Feeling thirsty
Dry skin or mouth
Urinating less than usual or having dark urine
Hard stools
Decreased sweating
Sunken eyes
Confusion
It’s important to follow your prescriber’s instructions carefully when taking Bumex. Taking more than what’s recommended makes dehydration more likely. If you experience symptoms of dehydration, talk to your prescriber right away. They may recommend adjusting your Bumex dose. If you have symptoms that feel severe, such as fainting, seek emergency care.
Frequently asked questions
Not necessarily. But older people may be more likely to experience dehydration or electrolyte problems. This is because we’re more likely to develop kidney, liver, or heart issues as we age, which can make dehydration and electrolyte changes from Bumex more likely. If you’re an older adult , your prescriber will likely start you on a lower dose to help avoid Bumex side effects.
We don’t have a lot of research comparing Bumex and Lasix (furosemide), which is a common loop diuretic. Bumex is considered at least 40 times as potent as Lasix, but this fact alone doesn’t mean it’s a better option. Talk to your prescriber about which option is best for you. Both medications can affect your kidneys.
It’s important to talk with your prescriber about your health history before starting treatment with Bumex or any diuretic. This can help them decide which medication is best for your condition.
Possibly, though they’re rare. For example, temporary hearing loss (ototoxicity) can occur with loop diuretics like Bumex. However, in rare cases permanent hearing issues might occur. Long-term hearing problems from Bumex are more likely if you have other hearing issues or regularly take Bumex with other medications that can affect hearing, such as nonsteroidal anti-inflammatory drugs (NSAIDs).
Most side effects caused by Bumex can either be managed with lifestyle changes or additional medications and supplements. If they’re not manageable, most side effects resolve after you stop taking Bumex.
The bottom line
Bumex (bumetanide) is a diuretic (water pill) used to treat fluid buildup caused by heart failure and kidney or liver disease. Bumex side effects are possible. Examples include muscle cramps, dizziness, and low blood pressure. These are likely caused by water loss (dehydration) or electrolyte imbalances that can occur while taking Bumex.
Serious side effects with Bumex are rare, but can include severe dehydration and severely low electrolyte levels. Talk to your prescriber if you experience dizziness, low blood pressure, or muscle twitching and cramps. If you have severe side effects, such as fainting or dark urine, seek emergency care.
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References
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Arumugham, V. B., et al. (2023). Therapeutic uses of diuretic agents. StatPearls.
Brater, D. C., et al. (1984). Bumetanide and furosemide in heart failure. Kidney International.
Cuthbert, J. J., et al. (2024). Diuretic treatment in patients with heart failure: Current evidence and future directions - Part I: Loop diuretics. Current Heart Failure Reports.
Ding, D., et al. (2016). Ototoxic effects and mechanisms of loop diuretics. Journal of Otology.
Frantz, R., et al. (2021). Stevens-Johnson syndrome and toxic epidermal necrolysis: A review of diagnosis and management. Medicina.
Huxel, C., et al. (2023). Loop diuretics. StatPearls.
Joo, Y., et al. (2020). The contribution of ototoxic medications to hearing loss among older adults. The Journals of Gerontology.
Mosenkis, A., et al. (2005). Muscle cramps and diuretic therapy. Journal of Clinical Hypertension.
Musini, V. M., et al. (2015). Blood pressure-lowering efficacy of loop diuretics for primary hypertension. The Cochrane Database of Systematic Reviews.
Oh, S. W., et al. (2015). Loop diuretics in clinical practice. Electrolyte & Blood Pressure.
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