Non-sedating Antihistamines


Acrivastine, Bilastine, Cetirizine, Desloratadine, Fexofenadine, Levocetirizine, Loratadine, Mizolastine, Rupatadine

   Issues for Surgery 


Loss of symptomatic relief of allergic rhinitis, hay fever and urticaria if omitted.

 For mizolastine – risk of QT-interval prolongation if continued.



  Advice in the Perioperative period 



Elective and Emergency Surgery
Continue


Post-operative Advice
If taken regularly, restart post-operatively as soon as next dose is due; otherwise restart when symptoms develop.


  Interaction(s) with Common Anaesthetic Agents 


None for acrivastine, bilastine, cetirizine, desloratadine, fexofenadine, levocetirizine and rupatadine1, 2, 3, 4, 5, 6, 7, 8, 9


QT-Interval Prolongation Mizolastine Mizolastine has a weak potential to prolong the QT-interval in some individuals, which might be additive with the effects of other drugs that prolong the QT-interval9, 10.  Concurrent use of mizolastine with other medicines known to prolong the QT-interval e.g. desflurane, isoflurane and sevoflurane, and possibly thiopental9, is contraindicated by the UK manufacturer10.


Loratadine
Whilst there are no conclusive reports of clinically relevant QT-interval prolongation with other non-sedating antihistamines there are a few case reports of torsades de pointes in patients taking loratadine9.  The clinical relevance of these cases is uncertain, but it is recommended that the QT-interval should be monitored if loratadine is given with other drugs that might potentially prolong the QT-interval9.


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



Macrolides 
Clarithromycin and erythromycin are predicted to increase the exposure to some non-sedating antihistamines either through inhibition of CYP3A4 (desloratadine, loratadine, mizolastine and rupatadine) or through P-glycoprotein (bilastine and fexofenadine)3, 6, 8, 9, 10, 11.  Acrivastine is expected to be similarly affected, however, they do not appear to have a clinically significant interaction with cetirizine or levocetirizine9

Concomitant use of clarithromycin is contraindicated by the manufacturers of mizolastine and rupatadine8, 9, 10.  Concomitant use of erythromycin is contraindicated by the manufacturer of mizolastine and cautioned by the manufacturer of rupatadine8, 9, 10.

Whilst single surgical prophylactic doses should not pose a problem in patients taking bilastine, desloratadine, fexofenadine or loratadine monitor for side effects if a prolonged course is required.

QT-Interval Prolongation
Mizolastine
Mizolastine has a weak potential to prolong the QT-interval in some individuals, which might be additive with the effects of other drugs that prolong the QT-interval9, 10.  Concurrent use of mizolastine with other medicines known to prolong the QT-interval is contraindicated by the UK manufacturer9. 10

Medicines that may be used in the perioperative period that are known to prolong the QT-interval include1, 9:- 
  • ciprofloxacin
  • clarithromycin – see also Macrolides above
  • domperidone
  • droperidol
  • erythromycin (particularly intravenous) – see also Macrolides above
  • granisetron
  • haloperidol
  • loperamide (increased risk with high doses)
  • ondansetron
  • prochlorperazine (theoretical risk) 

Loratadine
Whilst there are no conclusive reports of clinically relevant QT-interval prolongation with other non-sedating antihistamines there are a few case reports of torsades de pointes in patients taking loratadine9.  The clinical relevance of these cases is uncertain, but it is recommended that the QT-interval should be monitored if loratadine is given with other drugs that might potentially prolong the QT-interval9.

   Further Information 


None relevant. 


  References  


  1. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 2nd February 2021]
  2. Summary of Product Characteristics – Acrivastine 8mg Capsules, hard. Brown & Burk UK Ltd. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text July 2020]
  3. Summary of Product Characteristics – Ilaxten (bilastine) 20 mg tablets®. A. Menarini Farmaceutica Internazionale SRL. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text August 2019]
  4. Summary of Product Characteristics – Cetirizine 10mg Film-Coated Tablets. Dexcel Pharmaa Ltd. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text June 2019]
  5. Summary of Product Characteristics – Neoclarityn® (desloratadine) 5mg film-coated tablets. Pfizer Limited. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text January 2020]
  6. Summary of Product Characteristics – Telfast® (fexofenadine) 120mg Film-coated Tablets. SANOFI. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text October 2019]
  7. Summary of Product Characteristics – Levocetirizine 5mg film-coated tablets. Glenmark Pharmaceuticals Europe Ltd. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text December 2019]
  8. Summary of Product Characteristics – Rupatadine 10mg Tablets. Aspire Pharma Ltd. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text September 2020]
  9. Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 2nd February 2021] 
  10. Summary of Product Characteristics – Mizollen (mizolastine) 10 mg modified-release tablets. SANOFI Ltd. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text September 2019]
  11. Summary of Product Characteristics – Loratadine 10mg Tablets. Accord-Uk Ltd. Accessed via www.medicines.org.uk 2/2/2021 [date of revision of the text January 2021]