Colesevelam hydrochloride, Colestipol hydrochloride, Colestyramine

  Issues for Surgery

For hyperlipidaemia – increase in cholesterol if omitted for prolonged period.

For diarrhoea associated with Crohn’s disease, ileal resection, vagotomy, diabetic vagal neuropathy or radiation – exacerbation of symptoms if omitted.

For pruritus associated with partial biliary obstruction and primary biliary cirrhosis – exacerbation of symptoms if omitted.

Potential for reduced bioavailability of other oral medicines if continued – see Interaction(s) with Other Common Medicines in the Perioperative Period.

Potential risk of increased bleeding tendency, secondary to reduced vitamin K absorption – see Further Information.

  Advice in the Perioperative period

Elective and Emergency Surgery
Omit dose(s) on morning of operation.

Consider checking clotting screen pre-operatively in patients who have been taking bile acid sequestrants long-term and who are undergoing major surgery – see Further Information.

Post-operative Advice
Restart post-operatively once enteral intake resumed.

Ensure administration of bile acid sequestrant is separated from other oral medications to minimise effect on absorption (see Interaction(s) with Other Common Medicines in the Perioperative Period).

Patients undergoing Biliary Surgery
Review ongoing need for bile acid sequestrants post-operatively.

Patients undergoing Major Gastrointestinal Surgery
The safety and efficacy of colesevelam has not been evaluated in patients having major gastrointestinal surgery therefore the manufacturer advises caution1, 2.

  Interaction(s) with Common Anaesthetic Agents

None1, 2, 3, 4, 5.

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

Bile acid sequestrants may affect the bioavailability of other medicines; to limit this, bile acid sequestrant administration should be separated from other oral medicines (see figure 1 below).

Figure 1: Recommended time to administer other oral medications in relation to bile acid sequestrants1, 2, 3, 4, 5

  Further Information

Increased bleeding tendency
Chronic use of bile acid sequestrants may result in reduced absorption of fat-soluble vitamins, including vitamin K2. Hypoprothrombinaemia associated with vitamin K deficiency has been reported in patients taking colestyramine and a study noted prolonged prothrombin time in one patient taking colestipol3. Consider checking clotting screen in patients taking long-term bile acid sequestrants who are undergoing major surgery. If hypoprothrombinaemia is detected this usually responds to parenteral vitamin K administration2 – discuss with Haematologist if necessary.



  1. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. [Accessed on 7th March 2021]
  2. Summary of Product Characteristics – Cholestagel® (colesevelam) 625 mg film-coated tablets. SANOFI. Accessed via 07/03/2021 [date of revision of the text April 2017]
  3. Summary of Product Characteristics – COLESTID (colestipol) granules for oral suspension. Pfizer Limited. Accessed via 07/03/2021 [date of revision of the text July 2020]
  4. Summary of Product Characteristics – Questran Light® (colestyramine) 4g/sachet Powder for Oral Suspension. Cheplapharm Arzneimittel GmbH. Accessed via 07/03/2021 [date of revision of the text January 2021]
  5. Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. [Accessed on 7th March 2021]