Cinacalcet

  Issues for Surgery

Potential increase in parathyroid hormone and calcium levels if omitted.

  Advice in the Perioperative period

Elective and Emergency Surgery 
Continue.
Consider checking calcium levels pre-operatively – cases of QT-interval prolongation secondary to hypocalcaemia have been reported in patients taking cinacalcet¹. 

For patients who may decide to quit smoking during the perioperative period see Further Information.

Post-operative Advice 
Restart post-operatively as soon as next dose is due

  Interaction(s) with Common Anaesthetic Agents

 
None^{1, 2, 3}.

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

 
Analgesia
Codeine 
Cinacalcet is a potent inhibitor of CYP2D6¹ which is involved in the conversion of codeine to morphine³.  It is predicted that the efficacy of codeine might be reduced or abolished by cinacalcet^{2, 3} – monitor efficacy of codeine or consider alternative analagesia³. 

Tramadol
Cinacalcet is a potent inhibitor of CYP2D6¹; it is predicted to increase the exposure to tramadol, but to reduce the exposure to its active metabolite (which is responsible for its analgesic effect)^{2, 3}; tramadol adverse effects are therefore increased but not its analgesic effect³.  The clinical significance of this interaction is unknown.  Bear the possibility of an interaction in mind should a patient taking both medicines develop an increase in tramadol adverse effects³.

Macrolides 
Cinacalcet is partly metabolised by CYP3A4¹ therefore clarithromycin (a strong inhibitor of CYP3A4) is predicted to moderately increase the exposure to cinacalcet².  Parathyroid hormone and serum calcium levels should be monitored more frequently as dose adjustment may be necessary^{1, 2, 3}.  Weaker inhibitors of CYP3A4 (e.g. erythromycin) would be unlikely to cause clinically relevant increases in cinacalcet exposure³.

  Further Information

Smoking Cessation
Tobacco is known to induce CYP1A2 which is partly involved in the metabolism of cinacalcet¹.   Quitting smoking pre-operatively improves surgical outcomes through reducing risk of post-operative complications⁴.  If a patient decides to quit smoking during the perioperative period, it must be remembered that smoking cessation can reduce cinacalcet clearance.  Monitor parathyroid hormone and calcium levels closely as dosage adjustments are likely to be necessary^{1, 2, 3}.

  References

1. Summary of Product Characteristics – Mimpara®(cinacalcet) 30mg Film-coated Tablets. Amgen Ltd. Accessed via www.medicines.org.uk 03/02/2021 [date of revision of the text January 2020]
2. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 3^rd February 2021]
3. Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 3^rd February 2021]
4. Faculty of Public Health, The Royal College of Surgeons of Edinburgh, The Royal College of Anaesthetists, ash (action on smoking and health). Joint Briefing: Smoking and surgery. April 2016. Available at www.rcoa.ac.uk [Accessed on 3^rd February 2021]