Jeez, Neoliberalnot, I strongly suggest that you reconsider using old antibiotics. For one thing, old tetracyclines (like doxycycline) and aminoglycosides (like gentamycin, for example), can cause Fanconi syndrome. Fanconi syndrome is a renal dysfunction that can cause metabolic abnormalities.
Just something to consider.
I don’t have any aminoglycosides and I am aware they can cause renal damage like Fanconi syn. I was not aware that doxycycline was neprhotoxic—are you positive?