Enzyme inducers

Liver enzyme inducers can increase the metabolism of both oestrogen and progestogens.

Women using liver enzyme inducers may need a slightly higher dose of HRT to relieve symptoms. In addition, there should be consideration to using a higher dose of a progestogen to ensure adequate endometrial protection.

Examples of liver enzyme inducers include:

• Anti-epileptic medications such as carbamazepine, eslicarbazepine, cenobamate, fosphenytoin, oxcarbazepine, perampanel, phenobarbital, primidone, phenytoin, fufinamide and topiramate.
• Anti-retroviral medications such as efavirenz, nevirapine and ritonavir.
• Anti-bacterial medications such as rifampicin and rifabutin.
• Anti-fungal medications such as griseofulvin.
• St John's-Wort.
• Others include St John's-Wort, modafinil, bosentan, aprepitant, lumacaftor.