Pharmacokinetics hormone antagonists

Theoretically, the combination of an oestrogen antagonist such as tamoxifen and an aromatase inhibitor should provide additional benefit in the treatment of hormone-dependent cancers, however, no clinical studies have yet found this to be so. The pharmacokinetic interactions described above may partly explain this. It may be preferable to use these drugs sequentially rather than concurrently. ... 

Candesartan cilexetil 8 mg daily had no effect on the pharmacokinetics of ethinylestradiol and levonorgestrel in a combined oral contraceptive, and no ovulation occurred during concurrent treatment. No special precautions would therefore appear to be needed. Consider also Drospirenone + Potassium-sparing drugs , p.977, for a possible interaction between angiotensin II receptor antagonists and drospirenone, and Antihypertensives + Hormonal contraceptives , p.880. 

---