Selective progesterone receptor modulator

Overview of selective progesterone receptor modulators

Structure of the progesterone receptor (PGR) bound to a ligand.

A selective progesterone receptor modulator (SPRM) is a type of drug that acts on the progesterone receptor (PR) in a tissue-selective manner. SPRMs can have varying effects in different tissues, acting as agonists in some and antagonists in others. This unique property makes them useful in a variety of clinical applications, particularly in the fields of gynecology and reproductive health.

Mechanism of Action

Mechanism of nuclear receptor action.

SPRM drugs bind to the progesterone receptor, which is a type of nuclear receptor. Upon binding, they can modulate the receptor's activity, leading to changes in gene expression. The selective nature of SPRMs means that they can either activate or inhibit the receptor depending on the tissue type. This selectivity is due to differences in co-regulator proteins and receptor isoforms present in different tissues.

Clinical Uses

SPRM drugs are primarily used in the treatment of conditions such as uterine fibroids, endometriosis, and as emergency contraceptives. One of the most well-known SPRMs is ulipristal acetate, which is used for emergency contraception and the treatment of uterine fibroids.

Uterine Fibroids

SPRM drugs can reduce the size of uterine fibroids and alleviate symptoms such as heavy menstrual bleeding. They work by modulating the progesterone receptor in the uterine tissue, which is crucial for fibroid growth.

Emergency Contraception

Ulipristal acetate is used as an emergency contraceptive. It works by delaying ovulation and altering the endometrium, making it less suitable for implantation.

Research and Development

Research is ongoing to develop new SPRMs with improved selectivity and fewer side effects. The structure-activity relationship (SAR) of SPRMs is a key area of study, as it helps in understanding how different chemical modifications can affect the drug's selectivity and efficacy.

Structure-activity relationship of mifepristone analogs.

Side Effects

Common side effects of SPRMs include headache, nausea, and abdominal pain. Long-term use can lead to changes in the endometrium, which requires monitoring.

Also see

• Progesterone receptor
• Ulipristal acetate
• Mifepristone
• Nuclear receptor

• Birth control
• Contraception
• Dictionary of birth control
• Reproductive health