GENERAL ADVICE FOR USE WITH ENZYME-INDUCING DRUGS

Recommendations when taking enzyme-inducing drugs with hormonal contracep- tives (including the patch) include:

Women taking combined hormonal contraceptives should use an ethinylestradiol
dose of at least 50 micrograms daily. The dose may be increased further above 50 micrograms if breakthrough bleeding occurs. Note that, for those using the patch, the use of more than one patch is not recommended. Omitting or reducing the pill-free interval has not been shown to reduce the risk of ovulation with liver enzyme inducers. Additional non-hormonal methods of contraception, such as condoms, should also be used by patients using combined hormonal contracep- tives, both when taking the liver enzyme inducers and for at least 4 weeks after stopping the drug. Alternatives to all forms of combined hormonal contraceptives should be considered with long-term use of liver enzyme inducers.

The progestogen-only implant may be continued with short courses of enzyme
inducers. Additional non-hormonal methods of contraception, such as condoms, should also be used by patients using the progestogen-only implant, both when taking the liver enzyme inducers and for at least 4 weeks after stopping the drug. Alternatives to the progestogen-only implant should be considered with long-term use of liver enzyme inducers.

The progestogen-only pill is not recommended for use with liver enzyme inducers
and alternative methods of contraception are advised.

The effectiveness of the progestogen-only emergency hormonal contraceptive will be
reduced in women taking liver enzyme inducers.
An increased dose of levonorgestrel 1.5 mg immediately followed by another 1.5-mg dose 12 hours later may be used, although this is unlicensed. A copper IUD may be used as an alternative option.

Copper or levonorgestrel-releasing intrauterine devices (IUD) and depot progesto-
gen-only injections may be used as alternative contraceptive methods, particularly for women requiring hormonal contraception who are likely to be taking the enzyme inducer in the long-term, as these are unaffected by liver enzyme inducers.

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