Prescribing Premarin for Menopausal Patients
Start with Premarin 0.625 mg orally once daily, and you must add a progestin (medroxyprogesterone acetate 2.5 mg daily continuously or 10 mg for 12-14 days per month) if the patient has an intact uterus to prevent endometrial cancer. 1
Standard Dosing Regimen
For Women with an Intact Uterus (Most Common Scenario)
Premarin 0.625 mg orally once daily is the FDA-approved standard dose for menopausal symptom management. 1
Mandatory progestin supplementation options:
- Continuous regimen (preferred for avoiding withdrawal bleeding): Medroxyprogesterone acetate (MPA) 2.5 mg orally daily without interruption 2, 3, 4
- Sequential regimen (induces monthly withdrawal bleeding): MPA 10 mg orally daily for 12-14 days every 28 days 2
- Alternative progestin: Dydrogesterone 10 mg orally daily for 12-14 days per month 2
The continuous regimen achieves amenorrhea in 65% of patients immediately and in all patients by 12-15 months, with endometrial atrophy confirmed on biopsy. 4
For Women Post-Hysterectomy
Premarin 0.625 mg orally once daily without progestin. 1 No progestin is needed when there is no uterus, as the sole purpose of progestin is endometrial protection. 5
Exact Patient Instructions
Timing and Administration
- Take one tablet at the same time each day, with or without food 1
- Swallow the tablet whole with water 1
- If a dose is missed, take it as soon as remembered unless it's almost time for the next dose; never double up 1
What to Expect
- Hot flashes typically decrease from baseline to 0.5-0.9 per day by 12 weeks of treatment 6, 7
- If taking sequential progestin, expect withdrawal bleeding during the progestin-free days 2
- If taking continuous combined therapy, expect irregular spotting for the first 3 months, then amenorrhea 4
Critical Safety Warnings to Communicate
Immediately report these symptoms (venous thromboembolism warning signs):
- Sudden leg swelling, pain, or warmth 8
- Chest pain or shortness of breath 8
- Sudden severe headache or vision changes 1
- Sudden onset of slurred speech or weakness 1
Report these symptoms promptly:
- Abnormal vaginal bleeding (any bleeding if post-hysterectomy, or bleeding outside expected withdrawal pattern) 2, 1
- Breast lumps or nipple discharge 1
- Yellowing of skin or eyes 1
Dose Adjustments
If symptoms persist after 3 months on 0.625 mg:
- May increase to Premarin 1.25 mg daily 1
- If increasing estrogen dose with sequential progestin, no progestin dose adjustment needed 2
- If using continuous combined therapy with higher estrogen dose (1.25 mg), increase MPA to 5 mg daily 2
Use the lowest effective dose for the shortest duration consistent with treatment goals. 3, 5
Duration of Therapy
Continue treatment for symptom management, reassessing need annually. 5 The decision to continue beyond initial symptom control should weigh individual risks, family history, and severity of menopausal symptoms. 2
Common Pitfalls to Avoid
Never prescribe estrogen alone to a woman with an intact uterus - this dramatically increases endometrial cancer risk and is the most critical prescribing error. 5 Even women who are amenorrheic still require progestin if they have a uterus. 2
Do not start with doses higher than 0.625 mg - there is no additional benefit and increased harm with higher initial doses. 3, 5
Do not use ethinyl estradiol formulations - Premarin contains conjugated equine estrogens (17β-estradiol metabolites), which have a more favorable safety profile than synthetic ethinyl estradiol. 8, 1
Avoid progestins with anti-androgenic effects (such as cyproterone acetate or drospirenone) in women with sexual dysfunction or low libido, as these can worsen symptoms. 2, 3
Special Considerations
For women requiring osteoporosis prevention: Premarin 0.625 mg with appropriate progestin prevents bone loss equivalently to other hormone therapies, but should only be used when other osteoporosis treatments are not tolerated. 2, 7
Contraindications to verify before prescribing: