Premarin vs. Prometrium
See how Premarin and Prometrium compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Premarin is an estrogen that treats menopause symptoms directly, while Prometrium is a progesterone typically added to protect the uterus when estrogen is used.
Women with a uterus who take Premarin usually need Prometrium or another progestin alongside it to lower the risk of endometrial cancer.
Premarin costs roughly $240 to $290 a month, while Prometrium runs about $497 to $936 a month, so using both together adds up quickly.
Premarin vs. Prometrium Drug Summary
Premarin
Premarin is an estrogen hormone therapy, FDA-approved in 1942, used to treat moderate to severe menopause symptoms like hot flashes and vaginal dryness, as well as low estrogen from other causes. It's taken as a daily oral tablet available in several dose strengths, and it's also approved to help prevent osteoporosis and to palliate certain hormone-sensitive cancers.
Prometrium
Prometrium is a bioidentical progesterone capsule, FDA-approved in 1998, used mainly to protect the uterus in women taking estrogen therapy and to treat secondary amenorrhea. It's taken orally at bedtime on a cyclic schedule, and it's also used off-label for fertility support and combined hormone replacement therapy.
Premarin vs. Prometrium Side Effects
Premarin
Prometrium
Premarin vs. Prometrium Dosage
Premarin
Prometrium
| STAGE | DOSE | WHEN |
| Starting dose | 0.3 mg once daily | At the start |
| Maximum dose | 10 mg three times daily | If needed |
| Dose changes | 5 increases | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 200 mg once daily | At the start |
| Maximum dose | 400 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
Premarin
| STAGE | DOSE | WHEN |
| Starting dose | 0.3 mg once daily | At the start |
| Maximum dose | 10 mg three times daily | If needed |
| Dose changes | 5 increases | As tolerated |
Prometrium
| STAGE | DOSE | WHEN |
| Starting dose | 200 mg once daily | At the start |
| Maximum dose | 400 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
Premarin vs. Prometrium Indications
Premarin
Premarin is approved to treat moderate to severe hot flashes and vaginal dryness from menopause, along with low estrogen caused by other conditions. It's also approved to help prevent postmenopausal osteoporosis and, in select cases, to slow certain hormone-sensitive cancers.
Moderate to severe hot flashes of menopause
Vulvar and vaginal atrophy due to menopause
Low estrogen from hypogonadism, castration, or ovarian failure
Prevention of postmenopausal osteoporosis
Palliative treatment for advanced prostate or breast cancer
Prometrium
Prometrium is approved to protect the uterine lining in postmenopausal women who take estrogen therapy, since unopposed estrogen can raise the risk of endometrial cancer. It's also approved to treat secondary amenorrhea, and it's commonly used off-label for fertility support and combined hormone replacement.
Endometrial protection in women taking estrogen
Treatment of secondary amenorrhea
Off-label: luteal phase support in IVF
Off-label: combined estrogen-progesterone HRT
Off-label: PMS and PMDD symptom relief
Premarin vs. Prometrium Pros and Cons
Premarin
Premarin is one of the longest-used hormone therapies, offering multiple dose strengths to match different estrogen needs. It carries several boxed warnings, including for endometrial cancer and stroke, and it doesn't have a generic version available in the U.S.
Pros
Available in six dose strengths for flexible dosing
FDA-approved for multiple conditions beyond menopause, including osteoporosis prevention
Long-established safety and efficacy record dating to 1942
Lower monthly list price, roughly $240 to $290 versus Prometrium's $497 to $936
Cons
Boxed warning for endometrial cancer risk if used without a progestin
No FDA-approved generic version, which can affect insurance coverage
Requires added progestin therapy for women with an intact uterus
Boxed warning for increased stroke and blood clot risk
Prometrium
Prometrium is chemically identical to the progesterone the body produces, making it a common choice to offset estrogen's effect on the uterine lining. It carries a boxed warning for cardiovascular risk when combined with estrogen and is contraindicated for anyone with a peanut allergy.
Pros
Bioidentical to the progesterone the body makes naturally
Specifically used to protect the uterine lining during estrogen therapy
Cyclic dosing means it isn't taken every day of the month
Widely used off-label for fertility support during IVF treatment
Cons
Contains peanut oil, so it's contraindicated for anyone with a peanut allergy
Higher monthly cost, roughly $497 to $936 compared with Premarin
Not a standalone hormone therapy, it's added on top of estrogen
Cyclic schedule requires tracking specific days each month
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