Issues for Surgery
Potential for menopausal symptoms if discontinued.
Risk of venous thromboembolism (VTE) if continued (see Further Information).
Advice in the Perioperative period
Consider stopping 4-6 weeks before surgery where prolonged immobilisation is likely (e.g. abdominal surgery or orthopaedic lower limb surgery)1.
If continuing, ensure adequate thromboprophylaxis1.
Consider stopping on admission if prolonged immobilisation is likely.
Ensure adequate thromboprophylaxis1.
If discontinued pre-operatively, restart when fully mobile.
Interaction(s) with Common Anaesthetic Agents
Tibolone inhibited CYP3A4 in vivo leading to reduced midazolam metabolism1, 2; however, this is unlikely to be clinically significant2.
The manufacturers suggest drug interactions with other CYP3A4 substrates might be expected, although no case reports have been noted1, 2.
Interaction(s) with other Common Medicines used in the Perioperative Period
None1, 2, 3.
Risk of VTE
Data from an epidemiological study concluded that the risk of VTE in users of tibolone was lower than the risk with conventional hormone replacement therapy (HRT). However, due to limited data a small increase in risk compared with non-users of HRT could not be excluded therefore the manufacturers advise consideration should be given to stopping tibolone prior to major elective surgery1.
A Cochrane review did not find any difference in VTE when tibolone was compared with placebo although they noted the quality of evidence for this outcome was very low4. A recent observational study of the UK population included 368 women with VTE and 1859 controls who took tibolone. This study found tibolone was not associated with risk of VTE (p=0.8)5.