Short answer: Both are progesterone.12 The shot is 50 mg/mL in sesame oil, given into a muscle at 5 to 10 mg a day for six to eight days for stopped periods or abnormal uterine bleeding. Prometrium is a bedtime capsule in peanut oil: 400 mg for 10 days for stopped periods, or 200 mg for 12 days a cycle to protect the uterine lining with estrogen. Neither label covers IVF.
| Progesterone injection | Prometrium | |
|---|---|---|
| Form | 50 mg/mL in sesame oil with benzyl alcohol, 10 mL vial, into a muscle1 | 100 mg and 200 mg capsules of micronized progesterone in peanut oil, by mouth2 |
| Approved for | Amenorrhea; abnormal uterine bleeding from hormonal imbalance1 | Secondary amenorrhea; preventing endometrial hyperplasia in postmenopausal women on conjugated estrogens2 |
| Dose for stopped periods | 5 to 10 mg for six to eight consecutive days1 | 400 mg at bedtime for 10 days2 |
| Other dose | Abnormal bleeding: 5 to 10 mg daily for six doses1 | With estrogen: 200 mg at bedtime for 12 days per 28-day cycle2 |
| Side effects | Listed without percentages, such as spotting, injection site pain, swelling, breast tenderness and weight change1 | 3-year trial with estrogen: breast tenderness 27% vs 6% on placebo, dizziness 15% vs 9%, bloating 12% vs 5%2 |
| Allergy note | Not used with allergy to sesame oil or seeds1 | Not used with peanut allergy2 |
| Missed dose | No instruction in the label1 | No instruction in the label2 |
| Boxed warning | None1 | None in the current label2 |
Both labels warn about blood clots and sudden vision changes, and both are stopped if a clot is suspected.12 The injection label adds acute eosinophilic pneumonia linked to progesterone in sesame oil, generally 2 to 4 weeks after starting, with fever and shortness of breath.1 Prometrium can cause short-lived dizziness and drowsiness, which is why it is taken at bedtime, and its label carries the Women's Health Initiative findings on estrogen plus progestin.2
Neither label lists it. The progesterone injection label approves only amenorrhea and abnormal uterine bleeding, and Prometrium's approves only endometrial protection and secondary amenorrhea.12 Any other use is a decision for your prescriber, outside what these labels cover.
Which, if either, fits is for your prescriber. More detail: progesterone injection side effects, Prometrium side effects, the progesterone injection and Prometrium dosing schedules, the Prometrium missed-dose page, Prometrium vs Crinone: how do the oral and vaginal progesterone differ? and Crinone vs Endometrin: how do the vaginal progesterone products differ?.