Catheter maintenance solutions (Guidelines)


See also North Highland Community Catheter and Appliances Formulary.

Clinical evidence for the use of catheter patency solutions is limited. The decision to use a catheter maintenance solution must involve careful consideration of the potential risks and benefits for each individual patient.

Should encrustation be the cause of the problem a regimen may be developed to best prolong the catheter life and therefore spare the patient unnecessary potentially distressing and uncomfortable catheter changes. This is particularly important if the blockage has resulted in admission to hospital with retention of urine and resulting infection which is costly and time consuming to both patient and the medical team.

Uro-Tainer catheter maintenance solutions flowchart

Potential benefits

Use of the appropriate catheter maintenance solution can:

  • reduce the build up of mineral deposits or remove debris to reduce the frequency of catheter blockage and the need for re-catheterisation.
  • when used on a regular basis  prevent risk of bacterial colonisation, prevent or remove encrustation, eliminate blockage and stop debris formation
  • minimise urothelial damage by removing encrustation prior to catheter removal.
  •  prevent complications and unnecessary removal of the catheter.

Potential risks

Inappropriate use of catheter maintenance solutions:

  • there is evidence that all catheter maintenance solutions cause mucosal trauma in the bladder due to the physical process of administration. Damage may be worse if the solution is acidic or if force is used during administration, eg via a syringe.  This risk is reduced if the solution is instilled via gravity rather than forcing it in.
  • the risk of infection increases each time the closed catheter system is broken.
  • Catheter maintenance solutions may be used when re-catheterisation is the appropriate indication, which increases the interventions and delays appropriate treatment.
  • pain and discomfort can be experienced on administration.

Minimising the risks in practice

Before consideration of catheter maintenance solutions:

  • exclude other causes of catheter-related problems, eg constipation, kinked tubing , bladder overactivity , bypassing rather than blocked, fluid adaption.
  • inappropriate catheter choice – is the catheter large enough? Patients with persistently blocking catheters should have at least a size 16 insitu and be upsized at next change if not
  • If persistent blocking consider an ultrasound scan with a full bladder to rule out stones
  • only utilise catheter maintenance solutions where there is a clear indication and the benefit outweighs the risk of introducing infection.
  • pre-warm solutions by immersion in lukewarm water, connect to the catheter using aseptic technique and administer by gravity.
  • to minimise pain on administration consider using a smaller volume rather than the full 50 to 100mL. Only 15 to 20mL is required to bathe the lumen and tip of the catheter and can be repeated.
  • halt treatment if the patient experiences pain or discomfort on administration.

Choice of solution

The pH of the urine at the stage of blocking should be obtained and then the solution selected according to the pH. Try and be consistent in the time of day this sample is taken as pH varies at different times of day, and should be tested immediately.

Should the use of maintenance solutions be warranted, proper identification of the appropriate solution is essential.  For example, Saline is used as a mechanical ‘flush’ only and will not dissolve encrustation, whereas in the case of encrustation, an acidic solution is needed such as Suby G or Solution R.  

Note: Magnesium ammonium phosphate (struvite) and calcium phosphate crystals can form on the catheter tip, lumen and balloon under alkaline conditions (pH 7·5 to 9·5). Encrustation due to build up of these insoluble mineral deposits is associated with high urinary pH. Raised pH can help predict which patients would benefit from the use of catheter maintenance solutions. A prophylactic regimen can be utilised if the patient has a high urinary pH plus regular catheter blockage plus presence of encrustation in blocked catheter.

Note:   Chlorhexidine is of limited value in preventing or treating common infecting organisms and is therefore not recommended. Some of these organisms exist in a biofilm which resists surface washing of antibiotics.  Use of this solution is likely to lead to emergence of resistant organisms.

Uro-Tainer catheter maintenance solutions flowchart


  • Catheter patency solutions are licensed medical devices rather than medicines; Initiation can therefore be undertaken by either a prescriber or registered nurse or midwife with the appropriate training and level of competence; such initiation by a registered nurse or midwife should simply be recorded within the patient’s notes and/or care plan.
  • A patient held catheter Passport should be completed to chart the history of the catheter and changes.
  • As they are not licensed medicines they need only be prescribed to obtain a supply required in the community or where prescribers initiate treatment to be given by others.
  • All treatment should follow the guidance above.

Editorial Information

Last reviewed: 31/08/2020

Next review date: 31/08/2023

Author(s): Urology Department .

Approved By: TAM Subgroup of ADTC

Reviewer name(s): Kathleen Mackenzie, Urology Clinical Nurse Specialist .

Document Id: TAM408