Vaginal Diazepam for Pelvic Pain: Four Evidence Checks

A vaginal diazepam prescription may be offered when pelvic floor muscles remain tense and painful. This is an off-label use, meaning it is prescribed outside an approved indication. A 2024 US expert panel included vaginal muscle relaxants among options after pelvic floor physical therapy has not helped enough.¹

Did diazepam beat placebo?

Crisp’s 2013 trial² enrolled 21 women with high pelvic floor muscle tone confirmed by examination and electromyography, which measures muscle electrical activity. They used 10 mg vaginal diazepam or placebo for 28 nights. Diazepam showed no advantage in resting muscle activity or symptom questionnaires. The average age was 36. The author’s thesis reports only 14 completed, seven per group, after exclusions and missed follow-up.²

Holland’s 2019 trial³ randomized 49 women with pelvic pain and levator muscle spasm to 10 mg diazepam or placebo capsules. Only 35 had complete four-week data. Pain scores were 50 mm versus 39 mm on a 100-mm scale, respectively, with no statistically significant difference. Those are follow-up scores, not amounts of improvement. Small samples and missing data limit certainty; these trials do not establish worthwhile pain relief.³

Was it tested alongside rehabilitation?

In a 2018 trial⁴ of 42 women with vestibulodynia, both groups received vaginal electrical nerve stimulation, or TENS. Adding diazepam improved the painful-sex score more than adding placebo at 60 days, but did not significantly improve the separate vulvar-pain score between groups. Improvement in one outcome should not be described as improvement in every kind of pain.⁴

A 2024 pilot randomized 20 women to twice-weekly rehabilitation with or without nightly 5 mg vaginal diazepam. The combined group reported better pain outcomes at six months, but treatment was unblinded and menopause was an exclusion. There is also a reporting problem: the paper defines the Marinoff painful-sex scale as 0–3, yet lists a control-group average of 3.4. That inconsistency weakens confidence in its results.⁵

Does vaginal dosing stay local?

A 2019 absorption study⁶ gave eight healthy volunteers one compounded 10 mg vaginal suppository. Estimated bioavailability was 70.5%, meaning a substantial proportion reached systemic circulation. The average elimination half-life was 82 hours, and three of eight reported fatigue.⁶

The investigators warned that repeated daily doses could accumulate. This was a drug-level study in healthy volunteers, so it cannot show that suppositories relieve pelvic pain or establish safety with months of use.⁶

Why might clinicians give different recommendations?

NICE⁷ guidance for England says not to offer vaginal diazepam for pelvic floor dysfunction, including high muscle tone. Its committee cited the small negative trials and concern about dependency.⁷

The 2024 consensus of 11 US experts places pelvic floor physical therapy first, directed toward relaxation. It allows vaginal muscle relaxants alongside therapy when progress has plateaued or therapy cannot be tolerated. This is expert consensus rather than a new trial demonstrating diazepam’s effectiveness.¹

What to clarify before a prescription

Ask: “Which examination finding are we treating? What improvement would justify continuing this medicine, when will we assess it, and how does it fit with pelvic floor therapy?” Bring your full medication list for that discussion.

The When Sex Hurts section of Down There, Decoded explains how to describe the location, triggers and duration of pain and ask about pelvic floor therapy. Our painful-sex guide covers other possible causes to assess.