Premarin is a synthetic estrogen hormone replacement therapy (HRT) prescribed to treat unpleasant symptoms experienced during menopause. These include hot flashes, night sweats and vaginal dryness. Distributed by Wyeth Pharmaceuticals Inc., Premarin also protects against osteoporosis.
Most Common Side Effect
The most common side effect reported during clinical trials with Premarin was headaches, occurring in up to 32 percent of participants.
Other Side Effects
Other side effects experienced by between 10 and 17 percent of women included back pain, breast pain, joint pain, stomach pain and accidental injury.
Some gynecological side effects are common with Premarin use, such as breakthrough bleeding and other vaginal discharge. Heavy, cramping menstruation can occur as well. Vaginitis and yeast infections also are linked to Premarin use.
Less Common Effects
Less common side effects associated with Premarin include leg cramps, muscle pain or weakness, nervousness, gas, nausea, vomiting, bloating and colitis.
Increased risk for endometrial, ovarian and breast cancer has been documented with HRT use, but the risk is not high, according to a 2007 article in Sciencebase. Over five years, for example, ovarian cancer incidence for HRT users was 30 per 10,000, while the rate for women who had never used HRT was 26 per 10,000.