Hi,

I have been experienceing polyuria and flank pain since having taken a long course of doxycycline. I checked with the pharmacy and discovered that the doxycycline they dispensed to me was short-dated.

My doctor is concerned that the short-dated doxy (which could have been deteriorated) may have done renal damage. Deteriorated tetracyclines are nephrotoxic and can cause Fanconi-type syndrome, one symptom being the polyuria that I have experienced.

My question is, does a low specific gravity (it was 1.000, the same as water!) neccessarily indicate kidney damage? This was after one cup of coffee and no other liquids. Routine bloodwork (creatinine, BUN, etc.) was normal, as was the rest of the urinalysis (no glycosuria, proteinuria, etc. that I am aware of). Is it possible that there can be damage even if these tests come back normal?

I have an appointment with a specialist coming up, but in the meantime I've been stressed about this and would be very appreciative if anyone who knows about these things would provide their input. Thanks.

Sarah