Why are GPs worried about kidney function with losartan?

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When losartan reduces the decline in kidney function with age, and when it is used in high blood pressure in those with Type2 diabetic kidney problems, why, O why, won't GPs allow a larger daily does than 100mg per day?

I know the recommended daily maximum is 100mg daily but it's only recommended.

I can get my systolic down from 135-145 to 125-8 by increasing from 100mg to 150mg in two does per day.

This will surely do more good to my kidneys through reduced blood pressure, so why does my GP son say that he wouldn't go above the licensed daily maximum for some mumbled kidney reason?

After all, the license allows 150mg daily in heart failure so why not a little more to get over the liver metabolising the losartan too quickly through the day at 100mg daily.

Besides, I am only hitting the kidneys with a 75mg dosage at any one time whereas the product licence allows them to be hit with 100mg (daily).

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  • Posted

    pvf, if you have a good local pharmacist, why not put this question to her/him?  Pharmacists are much more knowledgeable with medications and how they work than GPs.

    Many BP pills can adversely affect the kidneys - I know from experience, struggling with high BP and the awful side effects from so many BP pills tried in the last year or so.  I have only one kidney and chronic kidney disease.  One pill further lowered my kidney function by as many as 8 points in just 3.5 weeks.  Luckily, the pill was stopped immediately and the function regained 7 of those points in the following month but I was so worried during that month leading up to the next blood test!

    As far as Losartan is concerned, it is the first BP pill that I have been prescribed that hasn't given my unbearable side effects.  However, it isn't controlling my BP either, and I'm not advised to increase from 50mg up to 100mg because of my reduced kidney function - the 50mg dose has already increased my creatinine levels, so 100mg would be a no-no.

    So be thankful that you have good kidney function now but please don't risk it for the future by self-medicating/increasing your Losartan dose against the advice of your GP.  I do hope you are being well monitored with blood tests

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    • Posted

      Mrs O, I appreciate your good concerns for my health.

      I consider that taking too low a dose of losartan will damage the kidneys through the high blood pressure, so I am prepared to take more than this ridiculous product licence daily maximum.

      My liver metabolises the 100mg so that it doesn't last the whole day, but the 75mg bd seems to have defeated it.

      However, about every 10 days, I feel unaccountably weary so I drop one dose in the day and, hey presto, I'm all right after that.

      I increased my dosage from 50mg bd (100mg daily) to 75mg bd in 12.5mg dose-rises over many weeks, monitoring my BP and my side effects, which were none.

      I do not see why you couldn't split your dose to 50mg twice daily and then take it up in 12.5mgs to, say, 62.5mg bd and see how your BP did.

      I don't expect my kidneys to function any less well on the higher dosage, especially when losartan slows down the age-related reduction in kidney function.

      However, it is essential to keep well hydrated, that is, well watered in the body by drinking fluids well and regularily through the day.

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    • Posted

      From what I've read from Google and from my own experience, my guess is that MrsO did not increase her fluid intake when the dose was increased.

      So, it might not have been the losartan as such but a failure to correct the losartan's tendency to increase the amount of fluid passing through the kidneys.

      From what I've seen on the internet, Losartan actually improves kidney functioning as it deteriorates with age, that is, it slows this age-related deterioration in kidney function.

      Perhaps by reducing the blood pressure pounding on the kidneys through its blood vessels.

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    • Posted

      Well you guessed wrong pvf!wink  I had a kidney removed 60 years ago so I have plenty of experience as far as knowing that I need to drink plenty of water, and I do.  In fact, I have respected the fact that I have one kidney throughout my life, eaten a very healthy diet, stayed away from alcohol and smoking, and had plenty of exercise.  Fantastically healthy until around the last 10 years, so I guess age is getting in the way!

      Losartan for me has shown an increase in my creatinine levels to above normal.  Increasing creatinine levels to above normal can have a knock-on effect of further lowering my eGFR.  Increasing the Losartan dose would worsen the present side effect.  

      Remember that blood pressure medication has originally been trialled on those who have two kidneys, never on anyone with only one.  So not possible to compare how I react to medication with how someone else will react.   I'm under a renal consultant and we're still working on finding something that will work on my blood pressure without adversely affecting my kidney function and vice versa.  Fingers crossed.  

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    • Posted

      OK, MrsO, I guessed wrong! There's nothing wrong in a guess because they are hypotheses.

      It just occurred to me that your creatinine level rose because the losartan was reducing the effectiveness of the angiotensin to retain water in your  bloodstream.

      Hey, ho! Best wishes.

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    • Posted

      Hi I know you left this comment over a year ago. Was just wondering if your creatinine continued to rise on losartan and if the losartan was discontinued did your GFR improve?
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    • Posted

      Lowered creatinine levels with losartan can indicate renal artery stenosis. Please check your physician to be sure he has ruled out this possible cause of your high BP
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    • Posted

      Kirsty,  Losartan is known to cause an increase in creatinine but as long as it is a small increase, the consultants accept this as a side effect of the medication and not significant as a problem with your kidney function as such.  If f course , if the creatinine when tested shows an increased

       then it will show a small reduction in e GFR but as long as the figure then remains stable, the renal consultants are not concerned.

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  • Posted

    Ah, the tyranny of the product licence for a drug!

    Even patient.info has caved in and changed the title from "Why won't GPs prescribe more than the daily recommended maximum?" to something about them being worried about kidney function.

    It's only a recommended maximum and if a patient's BP is better controlled on, say, 75mg bd than 100mg daily, then PRESCRIBE it.

    What are doctors being paid for? Answer: To avoid being censured by that bully of the GMC. Well, I thought it was to get better patients really better.

     

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  • Posted

    excellent info from pvf50286.

    The GPs never share some important details with patients, and think that all patients are medically illiterate compared to them.

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    • Posted

      The GP I had way back when my prostate first became a problem said 'You know more about this than I do'

       

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  • Posted

    As a losartan user myself, I have looked at various papers on the pharmacokinetics , pharmacogenomics, uricosuric effects etc. etc. Quite a lot of reading in fact.

    My personal take is that while losartan has been around a fair time and tested a lot, there are still things unknown about this drug+prodrug, such as its penetration into the brain, its allosteric effects on dopamine receptors (in the kidney at least) and of course unknown effects due to the limitations of medical knowledge..

    While it seems one of the better antihypertensive drugs from the POV of side-effects, I should not want to up my dose without talking to someone who was better qualified and more knowledeable than me. Personally. No advice intended.

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  • Posted

    I developed stage 1 CKD from years of ibuprofen abuse and am now trying to stop the degression or improve kidney function.  I also have HBP and took 50mg losartan for a few years. about a year ago my doc switched me to 150mg Irbesartan. He said it was like Losartan 1.0 which I understood as being better. my blood pressure is now always around 120/80 or below. any thoughts on Irbesartan?
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    • Posted

      It was Ibuprofen that did for me too as far as my sole kidney function was concerned, leaving me with CKD3a now progressed to 3b. I also have high BP and to date Losartan has been the only drug I can tolerate. Irbesartan is one that I haven't tried so far. Can I ask why you were switched from Losartan to Irbesartan?

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