A Phase 2 interventional study of Valacyclovir 500 MG and Placebo in Acute Apical Abscess and Pain, Acute, sponsored by University of California, San Francisco. Recruiting at 1 site in United States. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-05-30.
Sponsored by University of California, San Francisco · Phase 2, Interventional, and Treatment
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Among 351 studies in Acute Pain with a site in United States — 48 open to participants now, 53 under way, 1 of them phase 3. Acute Pain · United States.
Among the 351 studies in Acute Pain with a site in United States, this one is the 190th largest by planned enrollment of the 320 interventional ones that give a count, is one of 22 that started in 2023, is one of 54 in phase 2, reaches primary completion later than 6 of the 52 other live ones, and was the 250th registered.
1,075 studies on the registry are indexed under Acute Pain; 168 are open to participants now.
Browse Acute Pain studies →48 of the 351 studies in Acute Pain with a site in United States are open now. Recruiting first, the newest first:
Duke University · Sites in United States
Ages 18+ · Healthy volunteers
Aponia Laboratories, Inc. · Sites in United States, Germany
Ages 18–65
Florida State University · Sites in United States
Ages 18+
Eli Lilly and Company · Sites in United States
Ages 18–40
Ochsner Health System · Sites in United States
Ages 35+
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 103 Acute Pain studies recruiting now, 40 (39%) set no upper age limit and 50 (49%) stop at 75 or younger; 21 take children under 18; 24 take healthy volunteers.
This study: 18 Years to 80 Years · all sexes · healthy volunteers too.
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351 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 30 · Phase 2 63 · Phase 3 48 · Phase 4 66
First in 2001; this study’s year is marked. 22 started in 2023.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 60 is below the median of 86 across 903 interventional studies indexed under Acute Pain.
Median enrollment 84 across the 320 interventional studies, 100 across the 31 observational. Of the 265 that completed or were terminated, 131 (49%) have results posted.
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78 of 351 have an industry lead sponsor. The 10 most frequent:
University of California, San Francisco is the lead sponsor of 2,171 studies on the registry; 370 are open to participants now.
Of its 268 completed or terminated interventional studies of FDA-regulated products, 203 (76%) have results posted.
University of California, San Francisco has 6 studies filed under Acute Pain — fewer than ten, so there is no comparison to draw.
31 of the studies in Acute Pain 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 |
|---|---|
| NCT07930559Phase 3Aponia Laboratories, Inc.Effect of S-Ibuprofen Gel on Pain in Acute Soft Tissue Contusions | 2027-06 |
| NCT07511816Eli Lilly and CompanyA Study of LY4515100 in Participants With Pain Following Third Molar Removal | 2026-11 |
| NCT05335070Rutgers, The State University of New JerseyReducing Pain From Wisdom Molar Extractions | 2026-11 |
| NCT06795126Nationwide Children's HospitalLittle NIRVANA for Pediatric Pain and Anxiety | 2026-11-30 |
| NCT05458037Women and Infants Hospital of Rhode IslandRCT of Pain Perception With Fast and Slow Tenaculum Application | 2026-12 |
Add all 31 to your calendar (.ics) → With an account.
Among the 351 studies in Acute Pain with a site in United States, from their registry updates:
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The Virus in Endodontics (VE) phase I pilot study for preoperative pain will be analyzed and adjusted for the Phase II clinical trial. The Phase II clinical trial on preoperative pain, postoperative pain, and clinical healing will involve 250 patients. Patients will be recruited from the same pool of participants as the Phase II clinical trial. Preoperative cone beam computed tomography (CBCT) scans will be taken as well as three and six month postoperative CBCT scans. The secondary outcomes form the Phase II randomized clinical trial will be clinical success and visible radiographic healing determined by CBCT images.
This proposal is to test the valacyclovir+antibiotic treatment regimen that was developed during our pre-operative pain pilot study. Valacacylovir is a widely used medicine that is used to treat active herpesvirus. According to the figure 2 model of herpesvirus in symptomatic endodontic pathosis [1] the interventions aim to address the viral component of disease progression resulting in less pre-operative pain, post operative pain, and in faster healing of the associated lesion. Phase two involves recruitment of participants who: 1) present with swelling associated with an acute apical abscess originating from endodontic origin, 2) present with inadequate time or finances to proceed with either pulpal debridement or incision and drainage, 3) have undergone root canal therapy and present with a swelling associated with endodontic flare-up, or 4) have undergone pulpal therapy procedure, present with swelling associated with an endodontic flare-up, and require antibiotic treatment. Upon diagnosis of acute apical abscess, the patients will be invited to participate in the present study. Two groups will be divided randomly and patients will be given informed consent, verbally and written. Patients in the control group will receive a prescription for amoxicillin 500 milligrams (mg) (three times daily for 7 days), while patients in the intervention group will receive a prescription for amoxicillin 500mg + Valtrex (valacyclovir 500mg x three times daily for 7 days). During the 7 day follow-up period, patients will be actively monitored via telephone survey. The questionnaire will be performed by a dental assistant without knowledge of the clinical status of the patient. The questionnaire will be based on an 11-point numerical rating scale (NRS 0-10 scale). Patients will furthermore be asked to report the amount , if any, of analgesics used to manage symptoms.
Following the 7 day follow-up period patients will receive free endodontic treatment at University of California at San Francisco (UCSF) Postgraduate Endodontics Clinic. Non-surgical root canal therapy will be performed at the UCSF Dental Clinics by endodontic providers. Pre-operative CBCT scans will be taken. Customary therapy (root canal therapy) will be performed to treat the condition after the full course of antibiotics/antivirals have been completed (approximately 7 days following initial visit). Root canal therapy consists of removal of dental caries and infected pulp tissue, including debridement and disinfection of the internal root surfaces prior to filling. If the participant in the study experiences wishes to discontinue the study and seek emergency root canal treatment, pulpal debridement and/or incision and drainage will be performed as soon as possible. Intra-operative pain measurements using the visual analog scale (VAS) will be assessed. Participants will be followed up with a questionnaire for 7 days following root canal therapy. Participants will be asked the same questionnaire from the VE Preoperative phase which discovers the amount of analgesics needed for pain. Participants will return for recall examinations at 3 and 6 months. CBCT scans will be taken at the 3 and 6 month recall intervals.
Randomization : Consistent with the pilot study, phase II will use a random number generator to randomly assign a Manila packet containing either amoxicillin 500mg (three times daily for 7 days), or for amoxicillin 500mg + Valtrex (valacyclovir 500mg x three times daily for 7 days). Opaque medication packaging and using standardized verbal and written instructions helps ensure blindness of the phase II calibrated clinician, and patients of the therapeutic group they were assigned to.
Recruitment and Retention: 250 patients presenting with pain and a diagnosis of acute apical abscess will be recruited for the phase II preoperative pain and postoperative pain and clinical/radiographic healing phases of the clinical trial. The patients will represent the diversity of the San Francisco, California (CA) population. The anticipated retention rate is 90% for the phase II clinical trial, consistent with pilot study. Patients are likely to return for free endodontic treatment and thus analysis on the day of treatment will likely have a high retention rate. A decrease in retention likely at the 3 and 6 month recall visits due to the resolution of pain and thus lack of motivation to participate. Approved retention incentives such as free parking and transportation may assist in participant retention
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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.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
250 patients presenting with pain and a diagnosis of acute apical abscess will be recruited for the VEII preoperative pain and VEIII postoperative pain and clinical/radiographic healing phases of the clinical trial.
Drug: Valacyclovir 500 MG
250 patients presenting with pain and a diagnosis of acute apical abscess will be recruited for the VEII preoperative pain and VEIII postoperative pain and clinical/radiographic healing phases of the clinical trial.
Drug: Placebo
Consistent with the pilot study VEII will use a random number generator to randomly assign a Manila packet containing amoxicillin 500mg + Valtrex (valacyclovir 500mg x three times daily for 7 days). Opaque medication packaging and using standardized verbal and written instructions helps ensure blindness of the VEII calibrated clinician, and patients of the therapeutic group they were assigned to.
Consistent with the pilot study VEII will use a random number generator to randomly assign a Manila packet containing amoxicillin 500mg + Placebo (empty capsule). Opaque medication packaging and using standardized verbal and written instructions helps ensure blindness of the VEII calibrated clinician, and patients of the therapeutic group they were assigned to.
Measurement of pain levels following treatment intervention
Patients with an acute apical abscess circled the endodontic pain level from 0 to 10 .A predoctoral research assistant blinded to the study protocol phoned the study patients daily at a prearranged time to assess (1) pain level (Numerical Rating Scale \[NRS\]), and (2) analgesic use. NRS is a 1-dimensional scale that is quick and easily understood by patients. The NRS method assesses pain severity extremes, ranging from 0 to 10, and allows for both verbal (by telephone) and written administration. Different pain scales to quantify endodontic pain, such as the visual analog scale, are highly correlated with the NRS scale method.
Time frame: 3 years
Plan to share: No
No publications or documents are linked to this record.
Started Oct 2023 (actual). Primary completion is estimated for Dec 2025, 26 months after the start.
Of 40 phase 2 interventional studies under Acute Pain, half reached primary completion within 10 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 23. This study's planned 26 months is above that.
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Studies of the drug tested here: Valacyclovir
University of California, San Francisco →