A Phase 4 interventional study of Naproxen Sodium 550mg and Placebo in Dysmenorrhea, Chronic Pelvic Pain and Pelvic Pain, sponsored by Endeavor Health. Recruiting at 1 site in United States. Open to female participants aged 18 Years to 35 Years. Per ClinicalTrials.gov, last updated 2025-08-07.
Sponsored by Endeavor Health · Phase 4, Interventional, and Treatment
Among 68 studies in Dysmenorrhea with a site in United States — 9 open to participants now, 11 under way, 1 of them phase 3. Dysmenorrhea · United States.
Among the 68 studies in Dysmenorrhea with a site in United States, this one is the 6th largest by planned enrollment of the 62 interventional ones that give a count, is one of 7 that started in 2025, is one of 8 in phase 4, reaches primary completion later than 10 of the 10 other live ones, and was the 58th registered.
430 studies on the registry are indexed under Dysmenorrhea; 107 are open to participants now.
Browse Dysmenorrhea studies →9 of the 68 studies in Dysmenorrhea with a site in United States are open now. Recruiting first, the newest first:
Samphire Group, Inc. · Sites in United States
Ages 18–65 · Women only · Healthy volunteers
Western University of Health Sciences · Sites in United States
Ages 20–51 · Women only
Helaina Inc. · Sites in United States
Ages 18–40 · Women only · Healthy volunteers
Samphire Group, Inc. · Sites in United States
Ages 22–45 · Women only
Zenchi, Inc. · Sites in United States
Ages 20–45 · Women only
A study can be open while its sites in United States have not opened yet or have stopped. Only those recruiting at a site in United States →
Of the 57 Dysmenorrhea studies recruiting now, 7 (12%) set no upper age limit and 49 (86%) stop at 75 or younger; 11 take children under 18; 20 take healthy volunteers.
This study: 18 Years to 35 Years · female · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
68 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 4 · Phase 2 13 · Phase 3 16 · Phase 4 8
First in 2004; this study’s year is marked. 7 started in 2025.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 600 is above the median of 62 across 363 interventional studies indexed under Dysmenorrhea.
Median enrollment 73 across the 62 interventional studies, 291 across the 5 observational. Of the 51 that completed or were terminated, 21 (41%) have results posted.
This tab as a report to print or save as PDF → With an account.
41 of 68 have an industry lead sponsor. The 10 most frequent:
Endeavor Health is the lead sponsor of 111 studies on the registry; 34 are open to participants now.
Of its 12 completed or terminated interventional studies of FDA-regulated products, 9 (75%) have results posted.
Endeavor Health has 4 studies filed under Dysmenorrhea — fewer than ten, so there is no comparison to draw.
4 of the studies in Dysmenorrhea with a site in United States that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT04333576Phase 3AbbVieStudy Of Oral Elagolix Tablets In Combination With Combined Oral Contraceptive Capsules/Tablets To Assess Dysmenorrhea Response In Adult Female Participants With Endometriosis And Associated Moderate To Severe Pain | 2027-07 |
| NCT07524270Helaina Inc.Effera Dose Response: Women's Health | 2026-11 |
| NCT07679074Samphire Group, Inc.CREST: Samphire Guided Care Program on Wellbeing, Work Productivity, and Quality of Life | 2027-01-01 |
| NCT07508358Kevin HellmanVaginal Sildenafil for Primary Dysmenorrhea | 2027-06 |
Add all 4 to your calendar (.ics) → With an account.
Among the 68 studies in Dysmenorrhea with a site in United States, from their registry updates:
This tab as a report to print or save as PDF → With an account.
The goal of this clinical trial is to learn if NSAIDs (i.e. naproxen sodium) can treat menstrual pain and prevent the development of chronic pelvic pain in menstruating adults with painful periods. The main questions it aims to answer are:
Researchers will compare naproxen sodium to a placebo (a look-alike substance that contains no drug) to see if naproxen sodium works to treat painful periods.
Participants will:
The major goal of the study is to develop a multivariable statistical model (see https://grants.nih.gov/grants/guide/rfa-files/RFA-NS-24-021.html ) describing the factors that effectiveness of pain medication and risk for chronic pain
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this arm will be given naproxen sodium (550mg) as the study treatment, along with extended release acetaminophen (650mg) as a rescue medication. Participants are instructed to take 1 dose of naproxen sodium every 12 hours during the first 48 hours of their menstrual period. If participants do not feel adequate pain relief within 2 hours of taking a dose of naproxen sodium, they can take 1 dose of acetaminophen; they can repeat this process again in another 2 hours if needed for pain relief. Participants are instructed to follow this regime during each menstrual period for 1-year. Participants will not know whether or not they have received naproxen sodium or placebo, but they will know that they have been give acetaminophen as an optional rescue medication.
Drug: Naproxen Sodium 550mg · Drug: Extended Release Acetaminophen (650 mg)
Participants in this arm will be given a placebo capsule that is visually identical to the active drug as the study treatment, along with extended release acetaminophen (650mg) as a rescue medication. Participants are instructed to take 1 dose of the placebo every 12 hours during the first 48 hours of their menstrual period. If participants do not feel adequate pain relief within 2 hours of taking a dose of the placebo, they can take 1 dose of acetaminophen; they can repeat this process again in another 2 hours if needed for pain relief. Participants are instructed to follow this regime during each menstrual period for 1-year. Participants will not know whether or not they have received naproxen sodium or placebo, but they will know that they have been give acetaminophen as an optional rescue medication.
Drug: Placebo · Drug: Extended Release Acetaminophen (650 mg)
Participants will receive Naproxen Sodium 550 mg oral tablet, administered twice daily for the first 48 hours of their menstrual period, for 1-year. Naproxen Sodium is a nonsteroidal anti-inflammatory drug (NSAID) used for pain relief and inflammation reduction. 550 mg naproxen sodium is the highest FDA-approved starting dosage, equivalent to 500 mg naproxen; the sodium formulation quickens absorption.
Also known as: Aleve
Participants will receive a placebo oral tablet, identical in appearance to Drug X, administered twice daily for the first 48 hours of their menstrual period, for 1-year. The placebo contains inactive ingredients with no known therapeutic effect.
Participants may take extended release acetaminophen 650mg oral tablet as needed for breakthrough menstrual pain. Participants will be instructed to take 1 dose of acetaminophen after 2 hours of taking a dose of either naproxen sodium or placebo, only if needed for pain relief. They are able to take an additional dose of acetaminophen after 2 more hours have elapsed for continued breakthrough symptoms. Use of rescue medication will be monitored and recorded.
Also known as: Tylenol
M1 = Non-Menstrual Pelvic Pain (NMPP) Mediation by Menstrual Pain
"Non-menstrual pelvic pain (NMPP) will be assessed as the average of bladder, bowel, and non-menstrual pelvic pain ratings (0-10 scale) on non-bleeding days, excluding the two days before menstruation. Daily menstrual pain will be recorded during Menses (0-10 scale). The primary outcome is the reduction in NMPP at cycles 3,6,9, and 12, modeled using structural equation modeling to examine mediation by menstrual pain response to NSAIDs, accounting for endometrial inflammation (effluent cytokine levels). The mediation effect (M1) will be quantified using standardized path coefficients and indirect effects with bootstrapped 95% confidence intervals to determine the proportion of the NSAID effect on NMPP reduction. This outcome ranges from -1 to +1, with positive values indicating a worsening and negative values indicating a better mediation outcome.
Time frame: From enrollment to end of treatment at 1-year
V1= Non-Menstrual Pelvic Pain (NMPP) mediation by Visceral-Visceral Convergence (VVC)
In a structural equation model, VVC (bladder pain at first urge on 0-100 visual analog scale) and Multimodal Hypersensitivity) (reflecting widespread increased experimental sensitivity during the visual task, audio task, pressure pain tests, cold pressor, and conditioned pain modulation) will be constructed as a latent variable) mediation of the effect of NSAIDS on reductions in NMPP using a structural equation model. The mediation effect (V1) will be quantified using standardized path coefficients and indirect effects with bootstrapped 95% confidence intervals to determine the proportion of the VVC effect on NMPP. This outcome ranges from -1 to +1, with positive values indicating an worsening outcome and negative values indicating a better outcome.
Time frame: From enrollment to end of treatment at 1-year
Change in Non-Menstrual Pelvic Pain (NMPP) adjusted for holistic factors
Non-menstrual pelvic pain (NMPP) will be measured as the average of bladder, bowel, and non-menstrual pelvic pain ratings (0-10 scale) on non-bleeding days, excluding the two days before menstruation. Change in NMPP over time will be modeled using Structural Equation Modeling, adjusting for uterine inflammation (effluent prostaglandin concentration), sex hormones (estradiol, progesterone), and psychosocial factors (anxiety, depression, stress, sleep). The change in NMPP will be reported on a -10 to +10 scale, where -10 indicates improvement and +10 indicates worsening.
Time frame: From enrollment to end of treatment at 1-year
Trial effects of NSAIDs on Non-Menstrual Pelvic Pain (NMPP)
The impact of NSAIDs on non-menstrual pelvic pain (NMPP) will be assessed by comparing participants using NSAIDs to those on placebo. Treatment effects will be measured as the difference in NMPP scores between the NSAID and placebo groups over time (Baseline, 4, 8, and 12 months) using electronic daily diaries. NMPP will be recorded on a 0-10 scale, where 0 indicates no pain (better outcome) and 10 indicates severe pain (worse outcome)
Time frame: From enrollment to end of treatment at 1-year
Trial effects of NSAIDs on chronic pelvic pain
The impact of NSAIDs on chronic pelvic pain (CPP) will be assessed by comparing participants using NSAIDs to those on placebo. Treatment effects will be measured by the proportion of participants meeting diagnostic criteria for CPP based on electronic daily diaries at Baseline, 4, 8, and 12 months. CPP status will be reported as a percentage, where 0% indicates no CPP (best outcome) and 100% indicates all participants meeting CPP criteria (worst outcome).
Time frame: From enrollment to end of treatment at 1-year
Plan to share: Yes — The investigators will share these HEAL common Data Elements (CDEs): 1. Pain Intensity (PEG), 2. PROMIS Pain Interference, 3. PROMIS Physical functioning/quality of life, 4. PROMIS Sleep, 5. Pain catastrophizing (Sullivan 1995), 6. PROMIS Depression, 7. PROMIS Anxiety, 8. Global Satisfaction with Treatment (PGIC), 9. Substance Abuse (TAPS 1). The investigators will also share these HEAL-recommended demographics: age, sex at birth, gender identity, ethnicity, race, highest level of education, employment status, relationship status, annual household income, applied for disability insurance, pain duration, and postal code. The investigators will also share several data elements that lack a unified standard.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Time frame: Electronic copies of our research publications will be deposited in PubMed Central within four weeks of acceptance by a journal, complete with appropriate metadata to ensure discoverability and accessibility upon publication. All publications will be released under the Creative Commons Attribution 4.0 Generic License (CC BY 4.0) or an equivalent open-access license. There will be no embargo period for the public availability of our publications. The underlying primary data supporting our publications will be made widely accessible through DASH, a HEAL-compliant repository. To the extent feasible, The investigators aim to share the underlying primary data concurrently with the publication, ensuring immediate access. All primary data shared will be subject to the CC BY 4.0 license or an equivalent open-access license.
Access criteria: The IPD will be widely accessible via DASH, a Heal-compliant registry.
Data sharing details ↗ · dash.nichd.nih.gov
Started Apr 2025 (actual). Primary completion is estimated for Apr 2030, 60 months after the start.
How these figures are worked out, and which studies are left out of them.
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Studies of the drug tested here: Naproxen