overactive bladder

Furosemide is a diuretic that is one of the most prescribed drugs in the world. At last count over 7 million Americans swallow this water pill every day to lower their blood pressure or help their kidneys shed excess fluid. It is just behind another diuretic, hydrochlorothiazide (HCTZ), on the doctor’s hit parade of commonly prescribed medications. It is perceived as extremely safe, but furosemide (Lasix) side effects can be potentially serious if missed or ignored.

Furosemide is a “loop” diuretic, meaning that it affects a special part of the kidney called the loop of Henle to facilitate salt elimination from the body. This medication not only kicks sodium out of the body (considered a beneficial action), it also promotes removal of other key minerals such as magnesium, potassium and calcium (all undesired consequences). Many health professionals are aware of the potassium problem, but they may ignore the depletion of magnesium. This can have devastating consequences.

Furosemide (Lasix) Questions Received at People’s Pharmacy:

Q. My husband’s doctor is concerned about his blood pressure. It has been fine until three days ago when at the doctor’s office it was 140/80. (When we got home it was 125/75). The doctor doubled his dose of furosemide.

I frankly am afraid he is going to end up in the hospital! I would like to learn more about this drug. My husband fortunately works close to home; he sometimes urinates on himself because he can’t always make it to the bathroom in time. He does operate heavy equipment at times and the dizziness thing is scary too. Please tell us more about furosemide (Lasix) side effects.

Q. As part of the medications I take for high blood pressure, I take Lasix two times per day, 40 mg each.

I am concerned as I just read that Lasix can potentially cause kidney damage or gout when taken over a period of time. I am very concerned that I have never been told about these serious side effects from my doctor. Are they true?

 Q. I take prescribed 20 mg Lasix twice a day. One doctor says to take potassium with it, but another doctor says no. I don’t know what to do.

Q. My wife (54 years old) started furosemide 20 mg twice a day for fluid retention. It has helped with that, but has caused hearing loss in both ears. She has been told to stop for two weeks and see her doctor for blood work afterwards.

Q. I have a very good friend who suffers from serious heart problems. He had a pacemaker implanted many years ago. That was replaced with a defibrillator pacemaker. He has been taking many medications for his heart problems, including furosemide (Lasix). He was diagnosed with diabetes about three years ago.

A few months ago, he was taken to the ER when he became very short of breath. They ran many tests and one doctor switched him from Lasix to torsemide (Demadex). Ever since this change, his blood sugar has been completely normal. Is diabetes one of furosemide side effects?

Furosemide (Lasix) Side Effects:

As you can see from the questions above, this diuretic is associated with a number of unexpected complications. Because it is a water pill (eliminates fluid from the body), it can cause numerous trips to the bathroom. As one reader reported above, it led to incontinence for her husband at work. Others complain that they have to get up numerous times a night to pee.

More serious is dizziness. The same wife who worried that her husband had “accidents” at work also mentioned that he handled heavy equipment. The dizziness brought on by Lasix is very troublesome for someone in such a situation.

We also worry about depletion of potassium and magnesium. These electrolytes are essential for muscle function. When they are depleted from the body, muscle cramps are not an uncommon complication. Irregular heart rhythms can also occur and this can be a life-threatening situation if not corrected.

Anyone on furosemide must have regular blood tests to make sure electrolytes don’t get out of whack. In some cases potassium and magnesium supplements are necessary, but they require medical supervision and close monitoring to make sure the levels are like Goldilocks and the porridge (not too hot or too cold…too much or too little).

Other concerns mentioned above include hearing loss, gout and diabetes. These furosemide (Lasix) side effects should not be discounted. Diuretics not infrequently raise blood sugar or trigger diabetes. By now most people realize that this can have devastating results including an increased risk for heart disease, dementia, strokes and blindness. Gout can be incredibly painful. It can be brought on by excess uric acid levels in the body, a direct result of diuretics like furosemide or hydrochlorothiazide.

Other Furosemide (Lasix) Side Effects to be Alert For:

• Weakness, muscle cramps (linked to electrolyte depletion)
• Dehydration
• Irregular heart rhythms (contact an MD immediately!)
• Dizziness, low blood pressure, especially when standing suddenly
• Ringing in ears, hearing loss (contact an MD immediately)
• Blood problems (contact a physician if bruising or anemia occurs)
• Blurred vision
• Skin rash, itching (potentially life threatening, contact an MD immediately!)
• Elevated uric acid levels, gout
• Elevated blood sugar, diabetes
• Increases in cholesterol levels and triglycerides
• Kidney damage

No one should ever stop furosemide suddenly without medical supervision. This drug is essential for certain heart patients, especially those with congestive heart failure. Keeping excess fluid under control is critical for such patients. But furosemide is a tricky drug and requires very close monitoring by an attentive health care provider.

Furosemide can also interact dangerously with dozens of other medications, so the pharmacist must check any other medicine that is taken to make sure there are no incompatibilities. Always ask your doctor and pharmacist to check for drug interactions with furosemide. Here is why it is so important:

“My husband took furosemide for many years. We now know from the cardiologist who is caring for my husband that he was taking too many drugs that were not beneficial for him including furosemide. He was like a zombie–just wanted to sit and do nothing.

“After this cardiologist took my husband off this drug, plus others, plus prescribing something else instead and reducing the amounts of other drugs, my husband miraculously became alive again. He is now 86 years old and has survived two life-threatening surgeries. He is now very active and building things like he used to that he loved to do. He does many tasks and does not want to sleep all day, eats well and does so many other things.

“I am hoping people who take this drug and many others that you have written about will take heed and ask their doctors to check their drugs out very carefully. When my husband had surgery, he wasn’t recovering well. I found out that he was taking drugs that he shouldn’t have been. His cardiologist immediately started checking out what I had found and was amazed that all those other Drs. were not checking his meds, dosage, etc.

“Once again Dr. Gradeon and Mr. Gradeon, thanks for such a wonderful column and all the information you write about alerting and showing us so many natural remedies to use instead of harmful drugs.” Sincerely, Mrs W.

Furosemide and Generic Drug Substitution Problems:

We have received a number of complaints that not all generic furosemide is created equal. We are especially worried about this problem for people with heart failure. If their medicine is not working as anticipated, it can lead to fluid accumulation and life-theatening complications.

We fear that the FDA has not been as vigilant about monitoring generic drugs as most health professionals think. Here are just a few stories for your consideration. If you suspect that your generic furosemide is not working as intended, let your physician and pharmacist know that this is a problem other people have encountered.

“I have mild congestive heart failure and real bad edema, with my left leg especially. I take 80 mg Lasix twice a day. The brand name works quite well. Some of the generic furosemide seems to work but it seems to have a wide range of effectiveness from manufacturer to manufacturer.

“The generic furosemide that my mail order pharmacy sends me seems to do little or nothing. I may as well be taking chalk tablets. On this stuff I retained so much water that I would gain about 15-20 lbs or more and have shortness of breath. My legs would swell up badly. I have to keep a Lasix prescription at the local pharmacy and pay for it out of my own pocket to avoid problems.”

“I take furosemide, 20 mg tablets, and for a long time took Mylan brand generic. Then the pharmacy switched me to brand XXX generic. I immediately began ‘drowning,’ and my weight jumped 5 lbs overnight. I fortunately had some Mylan brand still on hand, switched back, lost the water, and three days later tried the brand XXX again. Same result. I am on an assigned Medicare Part D Plan, and as a result the Mylan has to be special-ordered and approved for me to get it.

“These are both generic forms of the same drug, but even among generics there are big differences. A major concern is that while I recognized the problem and took immediate action (and then tested the problem out again), there are a lot of elderly people on furosemide, for instance, who would not understand this type of problem with the pill. They could end up seriously ill, with their doctors blaming them for ‘non-compliance’ problems: “Mrs. D is not taking her furosemide as directed,” when in fact it was the drug manufacturer at fault.”

“Before I retired as a pharmacist, the two generic drugs that I received the most complaints about were generic Lasix and generic Ritalin.” Mark

Share your own story about furosemide (Lasix) below. Has it worked well for you? Have you experienced any side effects? Have you had any problems with generic formulations? Others may benefit from your comments. If you are taking furosemide for hypertension, you may find our Guide to Blood Pressure treatment of some value. It offers a number of non-drug options to discuss with your physician.

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  1. Kat
    NC, USA

    I had to take Lasik for all over edema with congestive heart failure. I took it as prescribed and it helped with the fluid. However, I started getting the worst muscle cramps I’ve ever had. And I mean just doing simple things like brushing my hair or reaching for something. The cramps were more awful at night and brought me to tears. I lost a lot of sleep. I told my cardiologist about this and he actually said to me, “I’ve been prescribing this med to hundreds of patients for years and no one has ever complained about this.” Made me feel like an idiot. But I know what I feel and I don’t care how many people have or don’t have the same side effects. My cardiologist also just casually said to buy some potassium and magnesium and that should help w/the cramps. Didn’t say how much to take per day or anything. Very careless if you ask me. Anyway, that’s been my experience. I’ll probably have to go to the hospital and get a Lasik IV because my stomach is really swollen right now. Good luck everyone.

    • Neese

      Hi Kat,

      The muscle cramps means that the Lasik has depleted your nutrients, such as Potassium. You should actually get your potassium levels checked and start taking the supplements as your Dr. suggested. When I had low potassium (from hydroclorothiazide), I was having the same issue and was rushed to the emergency room where they provided a potassium pill and I felt brand new after taking that. Good luck! :-)

  2. George

    Have been on Furosemide at 40 mg/day four years for congestive heart failure potential problem. About two years ago during Florida Summer heat and working outside I stopped taking it for urination convenience without doctors approval, and when cool weather came I stopped sweating—-ended up with severe congestive heart failure to ER. Now OK and take it daily without stopping. My new concern is potential kidney damage but the congestive heart problem is still there, thus I continue taking Furosemide.
    Be careful in stopping the drug- congestive heart is no picnic.

  3. Lynn
    Raleigh North Carolina

    My doctor took me off valsartan with hctz last year after I lost about 50 lbs because my blood pressure had dropped too low. I just took the kind without hctz and a while later when my blood pressure began to creep up again, she added furosemide. I’ve been on it for about 5 or 6 months now and having problems with my vision. I had a yearly check up in November and my prescription had changed ( I’d had cataract surgery on both eyes last year). Two months after my yearly eye exam I went back to my eye doctor because my vision seemed worse. It was. I had blurry vision but was able to use reading glasses. I went to the highest level I could find but eventually even reading glasses did not help. My eye doctor sent me to a retina specialist who found that my eyes are healthy. Yet today, six weeks later my optometrist could not correct my vision well enough to read most of the chart. According to her I have lost 3 lines on the chart ( which I’d been able to read in the past). She thinks it’s a waste of money to write a new prescription for glasses which will probably change in 2 months. As a last resort she’ll send me to a neurologist to find out what’s wrong. She thinks it could be the furosemide. Is that possible? I haven’t been able to find out much on my own. Thanks for any help/insight you can provide!

  4. Barbara
    Los Angeles

    About 4 years ago I was on Hydrochlorothiazide and it did not seem to work well alone so my doctor added the generic version of Lasix. When the Hydrochlorithiazide and the generic Lasix were taken together, they seemed to work best. My doctor told me to stop the Hydrochlorithiazide and just take the generic Lasix so I did. He also added Omprazole to my medications and kept prescribing the generic version of Zantac each time I filled my prescriptions. It seemed that my feet and ankles started to mildly swell witht he addition of Omeprazole so I stopped taking it and only took the generic Zantac. Then I went into the hospital to have my thyroid removed because of thyroid cancer and told them what medication I was taking. The nurses there had me taking both the Omeprazole and the generic Zantac even though I told them I was not taking both but they were refilled everytime I went to the pharmacist because that is what my doctor ordered.

    When the doctor on my case came in I discussed it with him and he told me to stop taking the generic Zantac and only take the Omeprazole because it was a better medication. I did and things went from bad to worse. The next time I was in to see my primary care doctor, I told him of the itching and the breakouts on my legs, shins, and feet and told him I think I am allergic to the Omeprazole. 3 doctors later and after running out of the Omeprazole, the swelling on my legs and over the rest of my body went way down. Process of elimination. No Omeprazole, no swelling. Never took it again. When I told my new primary care doctor, she ask me how I knew it was an allergy to the Omeprazole? I told her, process of elimination. No Omeprazole, no swelling, that is how I know.

    Now a year later I am still having cramping in my calves and breakouts on my lower legs/shins and my new primary care doctor will not take me off the generic lasix or test me for allergies to any of the medications I am on. I no longer know what to do. I went to a dermatologist for something else and showed him my legs but he did not know what to do as he said he never saw anything like that before. Can you offer any suggestions of where I should go or what I should be doing.

    By the way I am also on Simvastatin (which does cause cramping), Levothyroxine, Methocarbamol (for the cramping), Gabapentin (for the pain from the cramping and other nerve pain), Losartan Potassium, and Calcium +D. I was on one generic Lasix to start with, then they added a second one at night, then on in the afternoon, and because the swelling has not gone down totally they added a 4th. They just keep adding and do not listen to possible allergic reaction. Each generic Lasix is 40mg.

  5. Tommy
    Greensboro, NC

    Years ago, I was employed by the creator of Lasix. When generics first came out there were numerous failures. Our medical department explained the main reason for generic failures. Furosemide is chemically easy to duplicate. The problem was getting it buffered property so that it is readily and consistently absorbed. Plus generics only needed to be tested to plus or minus 20 % absorption in healthy individuals. Approved brand A could be a plus 20%. Then patient gets switched at the pharmacy to brand B, a minus 2O%. This could cause treatment failures.
    Finally, to control edema, it was better to increase the strength of the once a day dose, rather than go twice or three times a day. If 40mg didn’t control the edema, then go 80mg, etc. For BP control, a BID dose was recommended.

  6. Sharon
    Portland, OR

    My sister (age 87) and her daughter (age 63) were recently told by their doctors (each had different doctors) to stop taking their daily dose of 12.5 mg of Hydrochlorothiazide for blood pressure because it can cause memory loss, balance problems and loss of mental alertness in older people. I, too, take 12.5 mg of HCTZ and have e-mailed my own doc about this but, so far, have not received his response. Has anyone else any info regarding HCTZ?

    • Terry Graedon

      Hydrochlorothiazide can make potassium drop too low, which in turn could cause confusion. Older people might be especially susceptible. On the other hand, for those who tolerate it, HCTZ is a perfectly reasonable treatment for high blood pressure.

  7. Dee
    Atlanta, GA

    My doctor added HCTZ to my Lisinopril when my blood pressure got a little bit high. After taking it for about a week, I suffered with nausea, dizziness and dehydration. My doctor told me to go to the hospital for hydration. My electrolytes were way low (especially sodium). I ended up in the hospital for almost a week, and even then they couldn’t get my sodium back up. It was a scary experience and the EMTs said I was close to convulsions when I got to the hospital. My doctor told me he thinks I’m allergic to diuretics, something he had never seen before. So if you have bad symptoms, don’t wait long to get medical help. There are other things that can help blood pressure with fewer side effects.

  8. jan

    Fyi.. generic lasix (furosemide) seemed to cause forgetfulness.
    Switched to brand and it went away.

    Another issue: Does anyone know if blood in urine can be caused by Lasix?

    Would appreciate any information! Thanks.


    Been on furosemide 40 mg 3 times about 6 weeks and because it transformed me into a zombie, my MD dropped the dose t0 20 mg 3 times a week. Within another month my legs were so weak, I couldn’t walk at all. Waiting to hear from my cardiologist for advice.

  10. Richie S.
    Lebanon tn.

    I have been on furosemide close to 2 years. I take 160 mg a day to get excess water from my body and keep the swelling down in my legs. I manage to keep the swelling reasonably under controlA little swelling in late afternoon but down over night. I also have a kidney problem which is most likely the main reason for the high dose of furosemide. My legs are doing better and better each day, specially if I keep moving. Oh – I am 76 years old. Now I am having wetting problems and diapered 24/7. Next week I’m seeing a urologist docter but I think I prefer the diapers then more pills and tests. I feel great and can do most things except walk great distance. I have a heart – lung COPD) Kidney and anemia doctors and for the most part they agree with me

  11. Chuck

    I take Furosemide 40mg 3x daily and STILL have swollen legs, but more in the left leg. I’ve been on this for almost 4 years, I sleep with my feet elevated, and when I first wake for the day, that’s the ONLY time my lower legs and feet look and feel normal. I need to check on a different diuretic since it’s obviously not doing it’s job, except it’s robbing my body of potassium and everything else I take since I pee it all right back out of my body before it has a chance to do their jobs.

    I just and FINALLY got my Dr’s to prescribe me a potassium supplement after yet another ER visit and found to be hypokalemic yet again. MANY of the symptoms I’ve mentioned to my Dr. links directly back to a lack of potassium, so I advise anybody taking ANY diuretic, to have your blood checked OFTEN, not every 6 months like MY Dr. wants to do and thinks is fine. Do I need another Dr? You bet! But I live in a rural area and there just aren’t many choices, and on a fixed income I can’t afford to move closer to a town/city with more Dr’s to choose from.

    Educate yourself as much as possible and you may have to confront your Dr once in a while, because in spite of all the “degrees and diplomas” on the walls, they don’t know it all and sometimes just treat you like you’re part of an assembly line. Also, get to know your pharmacist, since they know more about meds than your Dr does. Luckily I’ve got a great couple of pharmacists, and I rely on them a lot. Take advantage of their knowledge, and most of the time they won’t mind sharing it with you at all. It could make a huge difference. They’ve helped me several times questioning my Dr about meds, and I was put on something else, or the existing prescription changed because it was too little or too much….like the potassium issue. On the paperwork from the hospital it CLEARLY states that any patient on furosemide is required to be on a potassium supplement. Now that I am, and still eating a healthy diet, I feel better than I have in 4 years. I feel alive again, instead of just existing.

  12. MIchael
    South Florida

    Lasix has been a God-send for me. I just worry about my fellow heart-failure patients who don’t understand the importance of being tough on themselves about a low sodium diet, in ADDITION to taking their Lasix as prescribed. The Lasix is not a “remedy” that you take so you can still have Chinese food every Sunday night. It must work in conjunction with your careful diet if it’s going to help you. Unfortunately, heart-failure is a progressive illness.

    However, if you’re diligent about your diet, and consistent with your dosage of Lasix, the progression of heart-failure CAN be slowed. I’m the proof. Get a great low-sodium cookbook and take care of yourself! The happiest benefit to come from my illness is that I’ve become a really great cook, and the kitchen has become my refuge! Cooking makes me happy, happy makes me healthy. I send best regards and good health to all who may read this. :)

  13. Shuger
    Kalkaska, MI

    I was on Lasix for years due to swelling legs…..I was allergic to the prilasec and no one seems to be aware of this. After establishing that I did not have heart problems and off the prilasec a few years, I went off the Lasix. The hair loss I was experiencing has stopped and my thoughts are a lot more clear. They (Dr.s) wanted me on anxiety drugs ect…..I feel so much better. I just can’t believe the difference. Also the swelling in my legs has gone down to about half of what they were On the drug.

    • Barbara
      Los Angeles

      Shuger, when you state prilasec, do you mean prilosec (Omeprazole)? If this is what you were referring to, I just want to let you know that Prilosec/Omeprazole can cause severe swelling in the legs, shins, and feet. I had a swelling so severe especially in the areas mentioned that I now have lymphedema and chronic venous statis from it. My doctors would not listen to me for 3 years and last fall I found out that it was an allergy for sure when I ran out of the medication and could not get in to the pharmacy for 3 weeks to get my prescription refilled. The swelling went down dramatically although not totally (because I feel I am still allergic to other medications I am on but still trying to figure out which ones so I know for sure).

      • Heabette

        After reading others comments, I feel I have confirmation about my concerns about the use of Lasix (and other drugs). NOW begins a new adventure in my health care (in my old age ) to weed out the chaff. My experiences with medication is similar to the other commentators.

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