Interactions

• patients with seafood allergies should avoid taking glucosamine (1) *
  • this is because glucosamine is manufactured by processing the crushed shells of crustaceans and therefore may lead to an allergic reaction in individuals who are allergic to seafood
• there have been reports suggesting an interaction between warfarin and glucosamine (an increase in INR has been noted in patients taking glucosamine supplements)
  • mechanism of any interaction is unclear however, patients on warfarin are recommended not to take glucosamine (1)

* there are differing statements regarding the use of glucosamine products and in patients with a history of shell fish allergy:

• The Anaphylaxis Campaign advises people with a history of shellfish allergy who wish to take glucosamine to be cautious, and ask for shellfish-free preparations (2); similarly, the Summary of Product Characteristics (SPC) for the licensed brands of glucosamine (Alateris, Dolenio, Glusartel and YOINTY) all contraindicate use of glucosamine in patients allergic to shellfish (3,4,5,6)
• an NHS review stated (7):
  • "..Glucosamine supplements are either produced synthetically or derived from the shells of shellfish, and should not precipitate allergic reactions in patients sensitive to shellfish. However, some sources contraindicate or recommend cautious use of these products in patients allergic to shellfish...."

Reference:

1. Current Problems in Pharmacovigilance 2006;31:1-12.
2. Anaphylaxis Campaign. Shellfish Allergy: The Facts [Internet]. Last updated September 2019 [cited 10/2/20]. Available at www.anaphylaxis.org.uk/wp-content/uploads/2019/09/Shellfish-Sep-2019.pdf.
3. Laboratoires Expanscience. Ltd. Summary of Product Characteristics. Alateris 625mg tablets. Date of revision of text 1/11/17 [cited 4/2/20]. Available at www.mhra.gov.uk/spc-pil/.
4. Mylan Products Ltd. Summary of Product Characteristics. Glusartel 1500mg powder for oral solution. Date of revision of text 5/2/19 [cited 4/2/20]. Available at www.mhra.gov.uk/spc-pil/.
5. Blue Bio Pharmaceuticals Ltd. Summary of Product Characteristics. Dolenio 1500mg film coated tablets. Date of revision of text 13/08/15 [cited 4/2/20]. Available at www.mhra.gov.uk/spc-pil/.
6. Reig Jofre UK Ltd. Summary of Product Characteristics. YOINTY 625mg hard capsules. Date of revision of text 10/12/19 [cited 4/2/20]. Available at www.mhra.gov.uk/spc-pil/.
7. NHS Specialist Pharmacy Service (February 2020). Glucosamine – what are the adverse effects?