Issues for surgery
For constipation – risk of constipation if omitted, particularly in patients with chronic laxative use, which may further be exacerbated by medication administered perioperatively, e.g. opioids.
For prevention of hepatic encephalopathy – risk of impaired consciousness and encephalopathy if omitted.
Advice in the perioperative period
Elective surgery
For constipation
Continue, if required.
EXCEPT:
- for patients having bowel cleansing preparations prior to surgery – stop when bowel preparation starts.
For prevention of hepatic encephalopathy
Continue.
EXCEPT:
- for patients having bowel cleansing preparations prior to surgery – stop when bowel preparation starts.
Emergency surgery
For constipation
Continue, if required.
EXCEPT:
- for patients with suspected bowel obstruction or perforation.
- for patients who are unable to tolerate the volume of fluid required for safe administration.
For prevention of hepatic encephalopathy
Continue.
EXCEPT:
- for patients with suspected bowel obstruction or perforation.
- for patients who are unable to tolerate the volume of fluid required for safe administration.
Post-operative advice
Resume post-operatively, if needed, once enteral intake resumed.
Due to the recommendation to drink around 1.5 – 2 litres of fluid with lactulose, review if the patient is nil by mouth or under a fluid restriction in the post-operative period.
If concomitant use of opioids or other medication that may cause constipation, or antibiotics that may cause diarrhoea, monitor response to treatment and adjust dose accordingly.
Review if patient develops reduced gastrointestinal motility (e.g. ileus) post-operatively.
Patients undergoing colorectal surgery
Review the need for lactulose post-operatively.
Interactions with common anaesthetic agents
None.
Interactions with other common medicines used in the perioperative period
Hypokalaemia
Lactulose may potentiate potassium loss induced by other medicines such as corticosteroids. This is unlikely to be an issue where corticosteroids are used as single doses to reduce post-operative nausea and vomiting or as cover for patients at risk of adrenal insufficiency. However, bear in mind and monitor serum potassium should continuedcorticosteroid treatment be necessary post-operatively.
Further information
None relevant.
References
Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed 23 March 2024]
Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press http://www.medicinescomplete.com [Accessed 23 March 2024]
Lactulose. In: Brayfield A (Ed), Martindale: The Complete Drug Reference. London: The Royal Pharmaceutical Society of Great Britain. http://www.medicinescomplete.com [Accessed 30 April 2024]
Summary of Product Characteristics – Duphalac® (lactulose) 3.335g/5ml Oral Solution. Mylan. Accessed 23 March 2024 via www.medicines.org.uk [date of revision of the text April 2022]