Breakthrough bleeding, with oral contraceptives

A possible interaction has been suggested with hormonal contraceptives and the herbal supplement St. Johns wort based on some reports of oral contraceptive users experiencing breakthrough bleeding shortly after starting St. Johns wort . Pregnancies have been reported by users of combined hormonal contraceptives who also used some form of St. Johns wort . Healthcare prescribers are advised to consult the package inserts of medication administered concomitantly with oral contraceptives... 

BZDs OESTROGENS, PROGESTERONES Reports of breakthrough bleeding when BZDs are co administered with oral contraceptives Uncertain The clinical significance is uncertain. It would seem to be wise to advise patients to use an alternative form of contraception during and for 1 month after stopping BZDs... 

Murphy PA,Kem SE, Stanczyk FZ, Westhoff CL. Interaction of St. John s Wort with oral contraceptives effects on the pharmacokinetics of norethindrone and ethinyl estradiol, ovarian activity and breakthrough bleeding. Contraception 2005 71 402-408. 

Possible altered efficacy of contraceptive reports of breakthrough bleeding when BZDs or meprobamate were co-administered with oral contraceptives... 

Adverse effects include nausea, weight gain, breast tenderness, and breakthrough bleeding. Oral contraceptives have also been associated with an increased incidence of thromboembolic disease, particularly in women who use tobacco products or have other risk factors for thromboembolism. The development of these complications is significantly reduced when low-dose estrogen formulations of oral contraceptives are used.3... 

High-dose monophasic preparations are indicated for the management of dysfunctional uterine bleedings and when persistent breakthrough bleedings occur with low-dose oral contraceptives. The monophasic combinations are taken in a fixed dose combination once daily over 21 or 22 days, followed by an interval of 7 or 6 days. 

Certain concomitantly administered drugs may interfere with the effectiveness of the oral contraceptives or lead to an increased incidence of breakthrough bleeding. These include rifampin, isoniazid, ampiciUin, neomycin, penicillin V, chloramphenicol, sulfonamides, nitrofurantoin, phenytoin, barbiturates, primidone, analgesics, and phenothiazines. 

Oral contraceptives Probable induction of cytochrome P450 metabolic pathway Reduced blood levels with risk of breakthrough bleeding Possible failure to prevent conception Weigh benefits of continuing use of SJW and possibiy reduced contraceptive effect... 

St. John s wort Mild to moderate depression Gastrointestinal upset, photo-sensitivity. Mild serotonin syndrome with the following medications paroxetine, trazodone, sertraline, and nefazodone. May decrease digoxin levels. May decrease cyclosporine serum concentrations. Combined oral contraceptives—breakthrough bleeding. 

There are also reports of complications associated with the combined use of oral contraceptives and St. John s wort owing to enzyme induction. The most frequent complication is breakthrough bleeding, although there are also reports of unwanted pregnancies (82,83). 

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