Dioralyte, Dioralyte Relief, St. Mark's Solution

 Issues for Surgery

Risk of fluid and electrolyte disturbances if omitted, particularly for patients with high output stoma (HOS).

  Advice in the Perioperative period

Elective Surgery
Continue – check electrolytes pre-operatively.

For dioralyte® – confirm reconstitution instructions with patient / carer (see Further Information).

Emergency Surgery 
Continue if appropriate.

It is likely that patients presenting for emergency surgery will require parenteral fluid therapy, in which case oral rehydration salts (ORS) should be discontinued.

For patients presenting with acute diarrhoea (Bristol Stool Chart types 5 – 7) that is not clearly attributable to an underlying condition (e.g. inflammatory colitis, overflow) or therapy (e.g. enteral feeding), consider assessing them for Clostridium difficile infection (CDI)1.

Post-operative Advice
Resume post-operatively, if needed, once enteral intake resumed. Monitor electrolytes and fluid balance closely.

Review if patient receiving intravenous fluid and electrolyte therapy or enteral nutrition post-operatively.  

Patients with impaired renal function should be closely monitored since overdosage of ORS may lead to hypernatraemia2.

Patients undergoing Stoma Reversal Surgery
If indicated for management of high output stoma (HOS), review the need for ORS post-operatively.

  Interaction(s) with Common Anaesthetic Agents

None2, 3, 4, 5.

  Interaction(s) with other Common Medicines used in the Perioperative Period

None2, 3, 4, 5.

  Further Information

St. Mark’s Solution
St. Mark’s Solution is a potassium-free, glucose-electrolyte mix that is used for the management of short bowel syndrome. It was developed by St. Mark’s Hospital in London, and it is an option for patients who are at increased risk of or experience hyperkalaemia with Dioralyteâ solutions. It is not commercially available, and patients are required to make up the solution daily.  

Double Strength Dioralyte
Dioralyteâ preparations are usually reconstituted as 1 sachet in 200mL or 5 sachets in 1 litre of water. However, for the management of high output stoma or fistula, it is common practice to use 10 sachets in 1 litre of water i.e. 'double strength’.


  1. Department of Health. Updated Guidance on the Diagnosis and Reporting of Clostridium Difficile. Published March 2012. Available at www.gov.uk [Accessed 26th September 2021]
  2. Oral Rehydration Solutions. In: Brayfield A (Ed), Martindale: The Complete Drug Reference. London: The Royal Pharmaceutical Society of Great Britain. http://www.medicinescomplete.com [Accessed on 26th September 2021]
  3. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 11th July 2021]
  4. Summary of Product Characteristics – Dioralyte® Blackcurrant Sachets. Sanofi. Accessed via www.medicines.org.uk 11/07/2021 [date of revision of the text February 2021]
  5. Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 11th July 2021]
  6. UK Medicines Information (UKMi). What is St. Mark’s Electrolyte Mix (solution). Date updated: November 2020. Available through the Specialist Pharmacy Service at www.sps.nhs.uk. [Accessed on 21st November 2021]