Have questions relating to my 89 year old mother who


Q: Have questions relating to my 89 year old mother who had reoccurring bladder infections for over 5 years. Was on preventative antibiotics such as nitro with elevated liver enzymes etc.
Anyhow - she had apprx 4 utis a year.
About half a year ago - she began 2000mg daily mannose sugar and has been uti free.
See uro study below


I believe for her its been effective. She historically has suffered from ecoli causing her incontinence, urgency and pain.
However, I just wanted to know the loading a sugar like this might have on the kidneys..
She began the sugar in April and 2.5 months later, her lab test
showed eGFR of 65 and creatinine of 71 (range of 60 -115)

Her CBC and urine tests were normal and the sugar is not metabolized in the body.

Deeming that the sugar comes from a good supplier - and contaminant free - how DOES one guage that the 2000mg daily wont cause taxing to the kidneys?
Please provide a succinct accurate answer showing some knowledge in this area or payment will be refuted


A:   Hi,
D mannose is a natural sugar as you know and has few side effects like diarrhea.

The upper limit dose is not specified clearly but in the research paper quoted by you, the dose is 2000 mg per day and the research was done for 6 months and at the end of it there was no alarming side effect in the patients.

In the absence of detailed studies, some doctors recommend taking d mannose in a dose of 500 mg twice daily for longer durations.

If kidney function tests are not showing any specific abnormal kidney function test results then 2000 mg d mannose daily has not caused any kidney associated dysfunction in your mother when she took it for 2 1/2 months.

It is important to know that since d mannose is a natural sugar therefore it is less likely to cause any kidney problems unless taken many times over recommended dose and over a longer duration.

I am sorry to state that an accurate answer is not available in context to consuming d mannose in recommended doses and kidney dysfunction however eGFR and creatinine are recommended tests for kidney function analysis.

It is important to know that GFR will decrease in the elderly population over 70 years and is a physiological variation.

Hope I could answer at least a part of your query.
Please do write back if you have any doubts.


Comments / Follow Ups

Patient: May I ask a number of followup questions
1. What kind of specialist are you? - your years of experience and country of practice?
2. So where do you get the 500mg twice a day from? I have only read that long term use
of high doses of this sugar may harm the kidneys but amounts are never specified
3. Am pondering reducing the amount to 1500mg daily and wait a few weeks but I dont
want a new full blown uti as she already is resistant to a couple of primary antibiotics
It has been difficult sometimes to treat the ecoli initially so 6 months has been her longest duration she has been ecoli free, I dont wish to jeopardize that. Your opinion
on staying at 2000mg than reducing at all?
4. How often should blood and urine testing be done to do checks?
5. I am attaching two uro reports August 12 and 16 - any comments to the results?
She also applies premarin twice a week 0.5 grams
Patient: 2 lab reports - urine 4 days apart in August 2016
Doctor: Hi,
Thanks for writing back with an update.

1. I am a doctor physician with over a decade of experience. I cannot provide more personal details myself as a part of employee guidelines at askthedoctor.com However you can write in to our support team and they are authorized to send you the details.

2. I have read numerous medical literature on the subject of d mannose used in preventing UTIs. One such article used a 1500 mg dose twice daily for nearly 6 months and there was no issues related to side effects.

You can read through the link below for complete details

In the above study the subjects were in the age range of 22 to 54 years. Therefore keeping in mind that your mother is 89 years old, it is suggested to go for a lower than normal adult dose and 500 mg twice daily fits in well.

3. In my opinion 2000 mg should not cause any problems but if she develops diarrhea then it should be reconsidered.

A 1500 mg daily is also acceptable. I suggest you start with 1500 mg a day and then if there is no problems in the coming 3 months then you can make it 1000 mg daily. This should not cause any problems.

4. Urine tests can be done once in 12 weeks and blood test only when she develops symptoms of fever and suspected high grade infections.

5. I feel there was contamination of the urine sample tested 12 August 2016. The test result of 16 August 2016 is acceptable.

D mannose should not cause any interactions with primarin.

Hope your query is answered.
Please do write back if you have any doubts.

Patient: The article you site above WAS NOT 1500mg twice a day but actually
"1 g 3 times a day, every 8 hours for 2 weeks, and subsequently 1 g twice a day for 22 weeks"
So that information is wrong.
I dont know where you get only 500mg twice a day.
I shall potentially try 1500mg a day vs 2000mg at the risk of a rebound ecoli infection.
In a way, it appears you have some knowledge about this supplement but when articles are poorly cited - it puts all information provided in doubt Dr UK
Doctor: Hi Sir,
Thanks for pointing out the error.

I agree it should have read 1000 mg when citing from the article, it is regretted. I honestly wanted to share the article with you.

It is to be noted that d mannose capsules are available in 500 mg dose to be given to children. Since your mother is 89 years old, therefore taking the lowest dose of 500 mg twice a day was suggested so that the kidney is safe.

However, 1500 mg a day is something which you can try since the kidney function is normal and I pray it works for her and prevents rebound infection.

Patient: Can you provide me the article which cites 1000mg a day whether in 1 dose or spilt up in 2 - 500mg. If 1000mg is what is deemed okay for a child but is that not enough for an adult body
Doctor: Hi Sir,
Please find the required information in the link below


It is a patent information and is quoted "The maintenance dosage for prophalaxis is one-half teaspoon (1 gram) 1 to two times per day."

Therefore my previous reply concerning 500 mg twice daily is the same which is mentioned above.


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