Diphenhydramine Phase 4 Trial for First Trimester Abortions
Summary
The NIH has registered Phase 4 clinical trial NCT07542730, a single-center, double-blind, randomized controlled trial evaluating intravenous diphenhydramine as an adjunct to standard moderate sedation for pain control during first trimester procedural abortions. Participants undergoing uterine aspiration at less than 13 weeks gestation will be randomized 1:1 to receive midazolam and fentanyl plus either diphenhydramine 50 mg or placebo, with primary outcome measured by participant-reported pain on a 100 mm Visual Analog Scale.
“Participants undergoing uterine aspiration at less than 13 weeks gestation will be randomized 1 to 1 to receive standard moderate sedation with midazolam and fentanyl plus either diphenhydramine 50 mg intravenously or matching placebo.”
What changed
The NIH has published a clinical trial registration for NCT07542730, a Phase 4 randomized controlled trial examining whether adding intravenous diphenhydramine to standard moderate sedation improves pain outcomes during first trimester procedural abortion. The study enrolls participants at less than 13 weeks gestation undergoing uterine aspiration, randomizing them to diphenhydramine 50 mg or placebo alongside standard midazolam and fentanyl. This is an informational registration entry on ClinicalTrials.gov and does not create compliance obligations for external parties.
Healthcare providers, clinical investigators, and pharmaceutical companies involved in reproductive health research may wish to monitor this trial for potential implications on sedation protocols and pain management practices. The primary endpoint is participant-reported pain using a 100 mm Visual Analog Scale.
Archived snapshot
Apr 21, 2026GovPing captured this document from the original source. If the source has since changed or been removed, this is the text as it existed at that time.
Diphenhydramine as an Adjunct to Moderate Sedation for Procedural First Trimester Abortions
Phase 4 NCT07542730 Kind: PHASE4 Apr 21, 2026
Abstract
This single center, double blind, randomized controlled trial will evaluate whether adding intravenous diphenhydramine to a standard moderate sedation regimen improves pain control during first trimester procedural abortion. Participants undergoing uterine aspiration at less than 13 weeks gestation will be randomized 1 to 1 to receive standard moderate sedation with midazolam and fentanyl plus either diphenhydramine 50 mg intravenously or matching placebo. The primary outcome is participant reported pain during uterine aspiration measured by a 100 mm Visual Analog Scale.
Conditions: Pain, Abortion, Anxiety
Interventions: Diphenhydramine, Placebo
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