General Information

Prometrium (progesterone) capsules contain micronized progesterone which is chemically identical to progesterone of ovarian origin. 

Prometrium Capsules are indicated for use in the prevention of endometrial hyperplasia in non-hysterectomized postmenopausal women who are receiving conjugated estrogens tablets. They are also indicated for use in secondary amenorrhea.

Prometrium capsules are intended for oral administration. Some women may experience difficulty swallowing the capsules. For these women, Prometrium Capsules should be taken with a glass of water while in the standing position. The recommended dosing is as follows:

• Prevention of Endometrial Hyperplasia: capsules should be given as a single daily dose at bedtime, 200 mg orally for 12 days sequentially per 28-day cycle, to a postmenopausal woman with a uterus who is receiving daily conjugated estrogens tablets.
• Treatment of Secondary Amenorrhea: capsules may be given as a single daily dose of 400 mg at bedtime for 10 days.

Mechanism of Action

Prometrium (progesterone) capsules contain micronized progesterone which is chemically identical to progesterone of ovarian origin. The oral bioavailability of progesterone is increased through micronization.

Side Effects

Adverse effects associated with the use of Prometrium may include, but are not limited to, the following:

• headache
• breast tenderness
• joint pain
• depression
• dizziness
• bloating
• hot flashes
• urinary problems
• abdominal pain
• vaginal discharge
• nausea

Clinical Trial Results

Prevention of endometrial hyperplasia

In a randomized double-blind clinical trial, 358 postmenopausal women, each with an intact uterus, received treatment for up to 36 months. The treatment groups were: Prometrium Capsules at the dose of 200 mg/day for 12 days per 28 day cycle in combination with conjugated estrogens 0.625 mg/day (n=120); conjugated estrogens 0.625 mg/day only (n=119); or placebo (n=119). The subjects in all three treatment groups were primarily Caucasian women (87% or more of each group). The results for the incidence of endometrial hyperplasia in women receiving up to 3 years of treatment are shown. A comparison of the Prometrium Capsules plus conjugated estrogens treatment group to the conjugated estrogens only group showed a significantly lower rate of hyperplasia (6% combination product vs. 64% estrogen alone) in the Prometrium Capsules plus conjugated estrogens treatment group, throughout 36 months of treatment.

Effects on secondary amenorrhea

In a single-center, randomized, double-blind clinical study that included premenopausal women with secondary amenorrhea for at least 90 days, administration of 10 days of Prometrium Capsules resulted in 80 percent of women experiencing withdrawal bleeding within 7 days of the last dose of Prometrium Capsules, 300 mg per day (n=20), compared to 10 percent of women experiencing withdrawal bleeding in the placebo group (n=21).

The rate of secretory transformation was evaluated in a multicenter, randomized, double-blind clinical study in estrogen-primed postmenopausal women. Prometrium Capsules administered orally for 10 days at 400 mg per day (n=22) induced complete secretory changes in the endometrium in 45 percent of women compared to 0 percent in the placebo group (n=23).