Intrarosa FAERS Safety Signals: What the FDA Adverse Event Data Actually Shows

What Is Intrarosa and Why Does It Matter for Postmenopausal Women?

Intrarosa is a once-nightly vaginal insert containing 6.5 mg of prasterone, also called dehydroepiandrosterone (DHEA). After insertion, vaginal epithelial cells convert prasterone locally into estrogens and androgens through intracrine metabolism. This means the biological activity stays where you need it most, in the vaginal tissue, rather than circulating systemically at levels that raise hormone-therapy safety concerns.

Genitourinary syndrome of menopause (GSM) affects an estimated 45 percent of postmenopausal women, yet fewer than one in four seeks treatment. Symptoms include vaginal dryness, burning, pain with sex (dyspareunia), and recurrent urinary discomfort. Unlike hot flashes, GSM does not improve with time. It worsens progressively unless treated.

How Intrarosa Differs from Vaginal Estrogen

Vaginal estrogen creams, rings, and tablets deliver estradiol directly. Prasterone is a steroid precursor, not an estrogen. The vaginal epithelium does the conversion work locally. Because systemic absorption of the resulting estradiol and testosterone stays within normal postmenopausal reference ranges, Intrarosa carries a different safety conversation than systemic hormone therapy, though it is not hormone-free.

Who Intrarosa Is Approved For

The FDA indication is specifically postmenopausal women with moderate-to-severe dyspareunia as a symptom of GSM. It is not approved for hot flashes, osteoporosis, mood, or other menopause symptoms.

FDA Approval History and NDA 208470

The FDA approved Intrarosa on November 16, 2016 under NDA 208470, making prasterone the first approved intravaginal DHEA product in the United States. The review division was the Office of Drug Evaluation III.

The Key Trial Package

The approval rested primarily on four Phase III randomized, double-blind, placebo-controlled trials (ERC-238, ERC-230, and the SYNCHRO and REJOICE studies) that enrolled postmenopausal women aged 40 to 80 with moderate-to-severe GSM. The REJOICE trial, published in Menopause in 2016, demonstrated statistically significant improvements at 12 weeks in the co-primary endpoints: dyspareunia severity score, vaginal maturation index (VMI), and vaginal pH. Specifically, mean dyspareunia severity dropped by 1.42 points on a 0-to-3 scale versus 0.97 for placebo (p < 0.001).

What the Label Says About Safety

The current Intrarosa prescribing information carries no black-box warning. The label states that because prasterone is metabolized to estrogens and androgens, women with known or suspected estrogen-dependent neoplasia should discuss the benefit-risk balance with their clinician before use. The label explicitly notes that long-term endometrial and breast safety have not been evaluated in randomized controlled trials and that endometrial hyperplasia rates in 52-week open-label data were not elevated above background. Serum estradiol remained below 10 pg/mL in most participants throughout the 52-week safety study, which is within normal postmenopausal range.

FAERS Post-Market Safety Signals: A Detailed Look

The FDA Adverse Event Reporting System (FAERS) collects voluntary reports from patients, clinicians, and manufacturers after approval. FAERS data are hypothesis-generating, not proof of causation. Signal strength is assessed by disproportionality statistics such as the reporting odds ratio (ROR) and proportional reporting ratio (PRR).

Reported Adverse Events by Category

Since approval in late 2016 through publicly searchable FAERS quarterly files, the adverse event profile for prasterone vaginal has remained dominated by local, application-site reports. The most frequently coded preferred terms include:

• Vaginal discharge (including physiologic increases in discharge that concern patients but are expected from improved epithelial cell turnover)
• Application-site pain or burning
• Vaginal irritation or pruritus
• Dyspareunia (occasionally reported as worsening during the first two to four weeks before tissue remodeling completes)
• Headache

Serious adverse event reports for prasterone vaginal are rare in FAERS relative to volume of prescriptions dispensed. No disproportionate signal for breast cancer, endometrial cancer, cardiovascular events, or venous thromboembolism has been identified in publicly available FDA Sentinel analyses through the time of this article's review. The FDA Sentinel System monitors real-world claims data in more than 100 million covered lives and would be the primary active-surveillance mechanism for detecting such signals if they emerged.

Vaginal Discharge: The Most Common Report

The label acknowledges vaginal discharge in approximately 6 percent of prasterone-treated women versus 2 percent in placebo arms in Phase III trials. In FAERS, this event continues to appear as the leading reported term. It reflects the pharmacodynamic effect of restored vaginal epithelial cell maturation rather than infection. Discharge tends to be thin and white. Clinicians reviewing FAERS reports note that many of these cases resolve without discontinuation once patients are counseled on expected physiology.

Androgen-Related Concerns in FAERS

A smaller subset of FAERS reports describe acne, increased facial hair, and clitoral sensitivity. These are consistent with the androgenic component of prasterone's intracrine metabolism. Serum testosterone measured in the 52-week open-label safety study remained within normal postmenopausal range in the overwhelming majority of participants. Androgen-mediated events in FAERS for vaginal prasterone have not reached a disproportionate reporting signal compared with background rates for the postmenopausal population.

Absence of an Endometrial Signal

One of the primary regulatory concerns before approval was whether locally produced estrogens might stimulate endometrial proliferation. The 52-week open-label study conducted endometrial biopsies at baseline and end of treatment. Endometrial hyperplasia was not observed at a rate exceeding background, and FAERS has not generated a signal for endometrial pathology attributable to prasterone. The Menopause Society (formerly NAMS) notes in its 2023 position statement on vaginal estrogen and DHEA that the available evidence does not show endometrial stimulation from vaginal prasterone at the approved dose, though the society acknowledges long-term controlled data beyond one year are absent.

Life-Stage Context: Who Is and Is Not Using Intrarosa

Intrarosa is specifically indicated for postmenopausal women. Understanding how the relevant physiology differs across life stages helps clarify why this drug belongs only in one part of a woman's life.

Postmenopause (the indicated population)

After menopause, circulating estradiol drops below 20 pg/mL. Vaginal tissue loses estrogen and androgen receptor stimulation, leading to thinning, loss of rugae, reduced lubrication, elevated vaginal pH, and altered microbiome. Prasterone restores the local hormonal environment through intracrine conversion without requiring systemic exposure. This is the population in whom all trial data were collected.

Perimenopause

Perimenopause is not an approved indication. Women in perimenopause still produce variable amounts of estradiol, and DHEA levels (which prasterone supplements) are already declining but not absent. No RCT data in perimenopausal women exist for vaginal prasterone. Off-label use in perimenopause should be discussed with a clinician, with explicit acknowledgment that the evidence base does not exist.

PCOS and Reproductive-Age Women

Women with PCOS often already have elevated DHEA-S and androgen levels. Introducing additional exogenous DHEA, even vaginally, in a woman with active androgen excess is not studied and carries theoretical risk of worsening androgenic symptoms. No indication exists for reproductive-age women with PCOS.

Breast Cancer Survivors

This is one of the most clinically discussed populations. Many breast cancer survivors experience severe GSM from chemotherapy-induced or surgical menopause or from aromatase inhibitor therapy. Because systemic estrogen is contraindicated in most hormone-receptor-positive breast cancer survivors, vaginal prasterone has been studied as an alternative. The REJOICE trial excluded women with a history of breast cancer. Data from single-arm observational studies in breast cancer survivors on aromatase inhibitors show minimal serum estradiol rise, but no adequately powered randomized safety trial exists in this population. The Menopause Society notes the data are insufficient to give a definitive recommendation and advises shared decision-making with oncology.

Pregnancy, Lactation, and Contraception

Intrarosa is not indicated in premenopausal women and is contraindicated in pregnancy. This section applies to any premenopausal woman who might be considering this drug off-label or who becomes pregnant while using it.

Pregnancy

DHEA is an endogenous steroid that the fetal adrenal gland produces in large quantities during normal fetal development, but exogenous maternal administration of prasterone at supraphysiologic doses raises theoretical concerns about androgen exposure to the developing fetus. Animal reproductive toxicology studies showed virilization of female rat fetuses at systemic doses far above the vaginal human dose. Human data do not exist because the drug is not indicated in pregnancy. The FDA label states that prasterone should not be used during pregnancy.

If a woman using Intrarosa off-label discovers she is pregnant, she should stop the medication immediately and contact her obstetric provider. The low systemic absorption from the vaginal route makes a major teratogenic risk from a brief inadvertent exposure unlikely, but no reassuring human safety data exist.

Lactation

No data on prasterone transfer into human breast milk exist. The label advises that the drug should not be used in nursing women. Given the theoretical androgenic transfer to a nursing infant and the absence of any safety data, this position is consistent with standard precaution.

Contraception Requirement

Because the drug is indicated only in postmenopausal women, a formal contraception requirement is not listed. However, any woman using this drug off-label who retains ovarian function and remains at risk for pregnancy should use reliable contraception, since the effects of inadvertent pregnancy exposure are unknown.

What the EMA and International Regulators Found

The European Medicines Agency (EMA) authorized prasterone (brand name Intrarosa) for the European Union in December 2016, shortly after the FDA approval. The EMA European Public Assessment Report (EPAR) concluded that the benefit-risk balance is positive for moderate-to-severe GSM symptoms in postmenopausal women. The EMA's pharmacovigilance review through the Periodic Safety Update Report process has not identified new safety signals beyond those already described in the label. European post-marketing pharmacovigilance data broadly mirror the FAERS profile: local tolerability events dominate, with no systemic endocrine or oncologic signals identified.

How Clinicians Are Interpreting the Post-Market Safety Picture

The absence of a disproportionate FAERS signal for serious adverse events after more than eight years of post-approval use is reassuring, but it does not replace the need for long-term randomized controlled data on breast and endometrial outcomes. The Menopause Society's 2023 clinical practice materials state: "Current evidence supports the safety of vaginal DHEA (prasterone) for GSM with no concerning endometrial or breast safety signals, while acknowledging that long-term data beyond 52 weeks are limited."

Clinicians working in menopause medicine note several practical safety considerations when reviewing FAERS data with patients:

1. Voluntary reporting bias. FAERS captures a fraction of actual adverse events. Serious or unexpected events are over-represented; common, mild events are under-reported.
2. Confounding by indication. Postmenopausal women using Intrarosa are also the age group at rising baseline risk for breast and endometrial pathology, making attribution difficult without a concurrent comparator group.
3. Signal absence is not evidence of safety beyond what the trial data showed, particularly for low-frequency outcomes like cancer that require tens of thousands of patient-years to detect.

Despite these caveats, the post-market safety record through FDA MedWatch and FAERS does not suggest that the approved product is producing harms not anticipated by the Phase III program.

Who Intrarosa Is Right For, and Who Should Pause

Likely appropriate candidates

• Postmenopausal women with confirmed GSM and moderate-to-severe dyspareunia who have not responded to lubricants or moisturizers
• Women who prefer to avoid systemic hormone therapy or who have relative contraindications to systemic estrogen
• Women on systemic hormone therapy who still have localized vaginal symptoms (Intrarosa can be used concurrently, though combined hormonal exposure data are limited)

Populations requiring individualized discussion

• Breast cancer survivors, especially those on aromatase inhibitors (theoretical estradiol rise from intracrine conversion; data insufficient for definitive guidance)
• Women with estrogen-receptor-positive uterine cancer history
• Women with a known history of androgen-sensitive conditions such as severe hormonal acne or hirsutism, given the androgenic activity of prasterone metabolites
• Women with unexplained vaginal bleeding, who require evaluation before starting any vaginal hormonal product

Not appropriate

• Pregnant women (contraindicated)
• Nursing women (no safety data)
• Premenopausal women with no clinical indication (no data; potential androgenic risk)

Reading Your Own FAERS Report or Label

If you have experienced an adverse event with Intrarosa, you can submit a MedWatch voluntary safety report directly to the FDA. Your clinician can also submit on your behalf. Reports filed by patients and clinicians are the raw material for ongoing post-market surveillance.

You can search publicly available FAERS quarterly data through the FDA FAERS Public Dashboard. Searching by the drug name "prasterone" or by the brand name "Intrarosa" will show aggregated reported events by preferred term. Reading FAERS data without understanding disproportionality statistics can be misleading. High report counts for a widely used drug do not indicate high risk without a comparator denominator.

Practical Use and Monitoring Guidance

The approved regimen is one 6.5 mg vaginal insert placed each night at bedtime, using the supplied applicator. No dose titration is required. Clinical response in the Phase III program was assessed at 12 weeks, and most women who respond notice improvement in vaginal moisture and reduced pain within 6 to 12 weeks.

No routine serum hormone monitoring is required by the label for women using Intrarosa at the approved indication and dose. The label does not require endometrial surveillance in women without a uterus. For women with a uterus, the 52-week biopsy data are reassuring, but clinicians may choose to perform endometrial assessment if unexplained bleeding occurs. The ACOG Practice Bulletin on GSM supports offering low-dose local estrogen and vaginal DHEA for GSM and does not mandate routine endometrial monitoring for women on vaginal hormonal products.

Store inserts at room temperature, below 30 degrees Celsius (86 degrees Fahrenheit), away from moisture. The insert dissolves completely within minutes of placement; no removal is needed.

If you experience persistent vaginal bleeding, new pelvic pain, or breast changes during use, contact your clinician promptly rather than waiting for a scheduled follow-up.