Livial Drug Interactions

Since Livial may increase blood fibrinolytic activity, it may enhance the effect of anticoagulants. This effect has been demonstrated with warfarin. Caution should therefore be exercised during the simultaneous use of Livial and anticoagulants, especially when starting or stopping concurrent Livial treatment. If necessary, the dose of warfarin should be adjusted.
There is limited information regarding pharmacokinetic interactions with tibolone. An in vivo study showed that simultaneous treatment of tibolone affects pharmacokinetics of the cytochrome P450 3A4 substrate midazolam to a moderate extent. Based on this, drug interactions with other CYP3A4 substrates might be expected.
Compounds that induce CYP3A4 activity such as barbiturates, carbamazepine, hydantoins and rifampicin may enhance the metabolism of tibolone and thus affect its therapeutic effect.
Herbal preparations containing St. John's wort (Hypericum perforatum) may induce the metabolism of oestrogens and progestogens via CYP3A4. Clinically, an increased metabolism of oestrogens and progestogens may lead to decreased effect and changes in the uterine bleeding profile.