There are isolated reports of breakthrough bleeding and failure of combined oral
contraceptives with
fluconazole,
itraconazole and
ketoconazole. Conversely, both
fluconazole and
itraconazole have been shown to modestly increase
serum levels of contraceptive steroids.
Although anecdotal reports suggest that these antifungals can rarely make hormonal contraception less reliable, the pharmacokinetic data suggest that, if anything, an enhanced effect of the combined hormonal
contraceptives is likely. Note that, of all the drugs proven to decrease the
efficacy of combined hormonal
contraceptives, all have also been shown to decrease the steroid levels. Further- more, the manufacturers do not advise any special precautions when taking oral
contraceptives and
azoles. However, some consider that the data warrant consideration being given to the use of additional contraceptive measures. The theoretical teratogenic risk from these
azoles may have a bearing on this.