Optimising delivery systems for HRT.
BACKGROUND
HRT has been used to alleviate vasomotor symptoms for more than 50 years, and since its introduction, ways have been sought to improve delivery methods, patient acceptability and tolerability. This paper reviews the benefits and disadvantages of some of the main HRT delivery systems currently available.


RESULTS
Oral methods of administration use high doses of estrogen because they are subject to metabolism in the intestine and liver. This results in systemic and physiological changes which can result in unwanted effects. Transdermal methods administer lower doses of estrogen to achieve the same therapeutic effect as oral methods. However, problems of adhesion and skin tolerability with conventional transdermal patches can lead to poor compliance with this method. Local administration by percutaneous gel or subcutaneous implant can use physiological doses of estrogen, but can be difficult to titrate, and may not offer the long term benefits associated with some oral and transdermal systems. Newer transdermal matrix systems are now available which offer improved skin tolerability and adhesion properties compared to some conventional transdermal systems.


CONCLUSIONS
There are a wide variety of delivery systems currently available and the choice of therapy must be made in consultation with women to aid compliance. Whilst oral administration has been a traditional first-line choice, it is not suitable for certain women. Newer generation transdermal matrix patches are usually suitable as a first line treatment in most women and can offer optimum profiles in terms of adhesion, tolerability and comfort, essential for good compliance and long-term treatment.
Stevenson
J C
JC
Imperial College School of Medicine, St Mary's Hospital, Endocrinology and Metabolic Medicine, London, UK. j.stevenson@ic.ac.uk
D000279:Administration, Cutaneous; D000284:Administration, Oral; D016503:Drug Delivery Systems; D004343:Drug Implants; D015914:Estrogen Replacement Therapy / Q000379:methods*; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D006801:Humans; D011372:Progestins / Q000008:administration & dosage
D004343:Drug Implants; D004967:Estrogens; D011372:Progestins