The ideal urine pH is 7.0–7.5 in dogs and 6.3–6.6 in cats. If the urine pH remains low after diet modification, potassium citrate can be administered in food to increase the pH. Because it complexes with calcium to form salts that are more soluble than calcium oxalate, citrate inhibits calcium oxalate crystal formation.
Urinary acidification is useful in the management of struvite (magnesium ammonium phosphate) uroliths. Ammonium chloride and dl-methionine are the urine acidifiers of choice.
Chronic urine acidification, and ensuing acidosis, can be harmful and should not be instituted without complete evaluation of the patient.
Walpole's solution—a mixture of sodium acetate (1.16%), glacial acetic acid (1.09%), and distilled water (97.75%) that has a pH of 4.5—is marketed as a treatment for dissolving struvite plugs in feline urethral obstructions by retrograde flushing through a urinary catheter. It has also been successfully used to treat urolithiasis in male goats via ultrasonographically guided cystocentesis and percutaneous infusion.
For dogs with ammonia-associated uroliths (eg, Dalmatians with urate stones and dogs with portosystemic vascular shunts), the urine can be alkalinized by potassium citrate. Alternatively, allopurinol is a xanthine oxidase inhibitor that can help dissolve urate uroliths.
