This would further serve to maintain satisfaction and compliance as high as possible. There is as yet no ideal preparation, suitable for all women, that functions as womens panacea. The former two are given orally, the latter may be given orally, transdermally, or subcutaneously. Oestrogen replacement therapy was originally introduced in the oral form. Since then patches, implants, gels and nasal spray preparations have been used.
Oral preparations have the advantage of being cheap, convenient, with a range of different types.
They can be combined with a cyclical or continuous progestogen should there be a need to protect the endometrium. A relatively large bolus of oestrogen is introduced to the systemic circulation, with levels peaking after 4-8 hours. With problems of reduced bioavailability and variable absorption, the plasma levels of oestradiol may be insufficient to achieve osteo-protection, or relief of climacteric symptoms. Oral preparations are subject to the hepatic first-pass metabolism effect. As a result of this, the production of coagulation factors and renin substrate is increased.