Overview

Progesterone is used to cause menstrual periods in women who have not yet reached menopause but are not having periods due to a lack of progesterone in the body. It is also used to prevent overgrowth in the lining of the uterus in postmenopausal women who are receiving estrogen hormone replacement therapy.

Indications

It is indicated for adjunctive use with estrogen in post-menopausal women with an intact uterus, as hormone replacement therapy (HRT).

Contraindications

When used in conjunction with oestrogens, the following apply:

• Known, past or suspected breast cancer
• Known or suspected estrogen-dependent malignant tumours (e.g genital tract carcinoma)
• Undiagnosed genital bleeding
• Thrombophlebitis
• Previous or current thromboembolism disorders (e.g. deep venous thrombosis, pulmonary embolism)
• Known thrombophilic disorders
• Acute liver disease, or a history of liver disease as long as liver function tests have failed to return to normal
• Known hypersensitivity to the active substances or to any of the excipients listed in section 6.1
• Porphyria
• Cerebral haemorrhage

Pharmacology

Pharmacodynamic Properties

Progesterone is a naturally occuring progestin or a synthetic form of the naturally occurring female sex hormone, progesterone. In a woman's normal menstrual cycle, an egg matures and is released from the ovaries (ovulation). The ovary then produces progesterone, preventing the release of further eggs and priming the lining of the womb for a possible pregnancy. If pregnancy occurs, progesterone levels in the body remain high, maintaining the womb lining. If pregnancy does not occur, progesterone levels in the body fall, resulting in a menstrual period. A progesterone trick the body processes into thinking that ovulation has already occurred by maintaining high levels of the synthetic progesterone. This prevents the release of eggs from the ovaries.

Pharmacokinetics Properties

Absorption:Progesterone absorption is prolonged with an absorption half-life of approximately 25-50 hours.
Protein Binding:96%-99%
Metabolism:Progesterone is metabolized primarily by the liver largely to pregnanediols and pregnanolones.
Route of Elimination: The glucuronide and sulfate conjugates of pregnanediol and pregnanolone are excreted in the urine and bile. Progesterone metabolites which are excreted in the bile may undergo enterohepatic recycling or may be excreted in the feces. Progesterone metabolites are excreted mainly by the kidneys.

Side Effects

Very rare but the common side effects are:

Mild nausea, diarrhea, bloating, stomach cramps;

Dizziness, spinning sensation;

Hot flashes;

Mild headache;

Joint pain;

Breast pain or tenderness;

Cough;

Acne or increased hair growth