Citric acid with potassium citrate

How it works

Citrate is metabolised to bicarbonate, which is excreted in the urine to raise urinary pH; alkalinisation increases the solubility of uric acid and cystine, while citrate also inhibits calcium stone crystallisation.

Prescribing in practice

• The potassium content can cause hyperkalaemia, so use with caution and monitor potassium in chronic kidney disease and in patients on potassium-sparing diuretics, ACE inhibitors or ARBs.
• Avoid in significant renal impairment with hyperkalaemia and in conditions where a sodium or potassium load is hazardous; it is for short-term symptomatic relief unless used for stone prevention.
• Urinary alkalinisation alters renal handling of some drugs and is not a substitute for antibiotics when an infection requires treatment.

Monitoring

Monitor serum potassium and, when used for stone prevention, urinary pH, particularly in renal impairment.

Counselling the patient

• Dissolve or take as directed with plenty of water and keep well hydrated.
• This eases urinary discomfort but does not replace antibiotics if you have an infection that needs them.
• Tell your prescriber if you have kidney problems or take blood-pressure medicines that raise potassium.

Evidence & guidelines

Potassium citrate is an established urinary alkalinising agent used for symptomatic relief in lower urinary tract infection and as part of metabolic stone-prevention regimens.