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Cesarean DeliveryPhase 4SPARENCT07534709

Suzetrigine for Opioid-Free Recovery After Cesarean Delivery

A Phase 4 study testing Suzetrigine in people with Cesarean Delivery and Cesarean Section, run by University of Texas at Austin at 1 site in United States.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

The goal of this clinical trial is to determine whether suzetrigine increases the proportion of patients who remain completely opioid-free from completion of surgery through 72 hours after cesarean delivery. Read more about this study

Who is it for?
Ages 18 years and older, women only
What is being tested?
Suzetrigine
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
90 participants
Where
1 siteUnited States
Study dates
Jun 2026to May 2028
Phase
Phase 4
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • Women only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Women aged ≥18 years.
  • Undergoing scheduled or unscheduled cesarean delivery during the current admission, with or without concomitant salpingectomy.
  • Planned delivery under neuraxial anesthesia (spinal, epidural, or combined spinal-epidural).
  • Planned Pfannenstiel skin incision.
  • Able to provide informed consent in English or Spanish.
  • Willing and able to complete required remote follow-up assessments through postoperative day 14 (POD14).

Who cannot join

  • Planned provision of breast milk to the neonate during the period of suzetrigine exposure (while the study drug is being taken and for 96 hours after last dose), due to the absence of human lactation safety data for suzetrigine.*
  • Known allergy, hypersensitivity, or contraindication to suzetrigine or any component of its formulation.
  • Chronic opioid use, defined as daily opioid use for more than 7 consecutive days in the month prior to delivery, or current treatment for opioid use disorder.
  • Significant hepatic disease, defined as AST or ALT >3 times the upper limit of normal or Child-Pugh class B or C.
  • Severe renal impairment, defined as estimated glomerular filtration rate (eGFR) <15 mL/min.
  • Concurrent use of medications known to significantly alter suzetrigine metabolism, including strong CYP3A inhibitors or inducers, such as:
Show all 18Show fewer
  • ketoconazole
  • ritonavir
  • carbamazepine
  • rifampin
  • St. John's wort (or other agents deemed clinically significant CYP3A modulators by the study investigator team)
  • Planned cesarean delivery under general anesthesia without neuraxial anesthesia.
  • Planned non-Pfannenstiel skin incision (e.g., vertical midline incision).
  • Participation in another interventional pain-management clinical trial during the current hospitalization.
  • Additional operative procedures (excluding salpingectomy) performed at the time of cesarean delivery (e.g., hysterectomy, hernia repair).
  • Inability to provide informed consent or to complete required study procedures and follow-up.
  • Receipt of opioid or sedating medications prior to completion of the informed consent process.
  • Feeding decisions are made independently of study participation. The study does not require participants to alter infant feeding plans; eligibility is determined solely by whether breast milk will be provided to the neonate during the period of study drug exposure (while the study drug is being taken and for 96 hours after last dose). Participants who plan to breastfeed but independently elect not to provide breast milk to the neonate during the period of suzetrigine exposure are eligible.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Chase Calvert, MD contact

512-771-0773

calvertchase@utexas.edu

United States1 site

  • University of Texas at Austin Dell Medical School, Department of Women's Health

    Austin, Texas, 78705

    Chase Calvert, MD, 5127710773, calvertchase@utexas.edu

    Lorie M Harper, MD, MSCI

Other trials in United States

About this study

Official title: Suzetrigine Versus Placebo for Opioid-Free Recovery After Cesarean Delivery: A Randomized Controlled Trial

The goal of this clinical trial is to determine whether suzetrigine increases the proportion of patients who remain completely opioid-free from completion of surgery through 72 hours after cesarean delivery.

The main question it aims to answer is:

Read more

Does adjunctive suzetrigine, when added to a standardized multimodal postoperative analgesic regimen, increase the proportion of patients who remain opioid-free during the first 72 hours after cesarean delivery?

Researchers will compare suzetrigine to a placebo (a look-alike substance that contains no drug) to evaluate this outcome.

Participants will:

  • Receive either suzetrigine or placebo after cesarean delivery
  • Receive standard postoperative pain management, including acetaminophen, nonsteroidal anti-inflammatory drugs, and neuraxial morphine
  • Have opioid medications available as needed for breakthrough pain
  • Be followed during hospitalization and after discharge to assess pain, recovery, and medication use
Read the detailed description

This is a single-site, randomized, double-blind, placebo-controlled clinical trial evaluating whether adjunctive suzetrigine increases the proportion of patients who remain opioid-free following cesarean delivery. The study is conducted at a tertiary care academic medical center.

Participants undergoing cesarean delivery under neuraxial anesthesia are randomized in a 1:1 ratio to receive either oral suzetrigine or a matching placebo following surgery. Randomization is performed using a computer-generated sequence with permuted blocks of variable size and allocation concealment through a secure electronic system. Participants, clinicians, investigators, and study personnel are blinded to treatment assignment.

The intervention consists of oral suzetrigine administered in the immediate postoperative period, beginning with a loading dose within 90 minutes after skin closure, followed by scheduled maintenance dosing every 12 hours. Participants randomized to the control arm receive a matching placebo on the same schedule. Study medication is prepared and dispensed by the investigational pharmacy in identical packaging to maintain blinding.

All participants receive standardized multimodal postoperative analgesia consistent with institutional enhanced recovery pathways, including scheduled acetaminophen and non-steroidal anti-inflammatory drugs, as well as neuraxial morphine administered intraoperatively. Opioid medications remain available for breakthrough pain at the discretion of the clinical care team.

Suzetrigine is a selective NaV1.8 voltage-gated sodium channel inhibitor that targets peripheral nociceptive pathways and does not act on opioid receptors. This study evaluates its use as an adjunct to standard multimodal analgesia in a postpartum surgical population in which opioid exposure remains common despite guideline-recommended care.

Participants are followed during their inpatient hospitalization and through the early postpartum period using a combination of electronic medical record data and structured follow-up assessments to capture medication use, recovery, and patient-reported outcomes. Data are recorded using secure electronic data capture systems with predefined data fields and standardized collection procedures.

Analyses will be conducted using an intention-to-treat approach, with comparisons between randomized groups based on pre-specified analytical methods appropriate for outcome type.

Participant safety is monitored throughout the study period through routine clinical care, structured follow-up assessments, and oversight by an independent data safety monitoring board.

Being tested
Suzetrigine, Placebo
Keywords
suzetrigine, Cesarean Delivery, cesarean section, postoperative pain, opioid-free recovery, opioid-sparing, multimodal analgesia, postpartum opioid use, NaV1.8 Inhibitor
Medical subject headings
Pain, Postoperative

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • SuzetrigineDrug

    Oral suzetrigine administered following cesarean delivery as an adjunct to standardized multimodal postoperative analgesia, including scheduled acetaminophen and nonsteroidal anti-inflammatory drugs, with opioid medications available as needed for breakthrough pain.

  • PlaceboDrug

    Matching oral placebo administered following cesarean delivery in addition to standardized multimodal postoperative analgesia, including scheduled acetaminophen and nonsteroidal anti-inflammatory drugs, with opioid medications available as needed for breakthrough pain.

Study groups in NCT07534709
Study groupRoleWhat they receive
SuzetrigineExperimentalParticipants will receive oral suzetrigine following cesarean delivery in addition to standardized multimodal postoperative analgesia, including scheduled acetaminophen and nonsteroidal anti-inflammatory drugs, with opioid medications available as needed for breakthrough pain.
Receives: Drug: Suzetrigine
PlaceboExperimentalParticipants will receive matching oral placebo following cesarean delivery in addition to standardized multimodal postoperative analgesia, including scheduled acetaminophen and nonsteroidal anti-inflammatory drugs, with opioid medications available as needed for breakthrough pain.
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Proportion of Participants Remaining Opioid-Free Through 72 Hours Postoperatively

    Proportion of participants who do not receive any opioid medications from completion of cesarean delivery through 72 hours postoperatively.

    Measured: From completion of surgery to 72 hours postoperatively

Secondary outcomes (6)

  1. Postoperative Pain Intensity Scores

    Patient-reported pain intensity measured using the Numeric Rating Scale (NRS) for pain, an 11-point scale ranging from 0 to 10, where 0 indicates no pain and 10 indicates the worst possible pain. Higher scores represent greater pain intensity.

    Measured: During hospitalization through 72 hours postoperatively

  2. Maternal Satisfaction With Pain Management

    Participant-reported satisfaction with postoperative pain management assessed using a single-item Likert-type scale ranging from 0 to 10, where 0 indicates completely dissatisfied and 10 indicates completely satisfied. Higher scores indicate greater satisfaction.

    Measured: At hospital discharge and postoperative day 14

  3. Functional Recovery After Cesarean Delivery

    Functional recovery assessed using the Obstetric Quality of Recovery-11 (ObsQoR-11) questionnaire, a validated 11-item patient-reported outcome measure evaluating multiple domains of postoperative recovery, including pain, physical comfort, functional independence, and ability to care for the newborn. Each item is scored on an 11-point numeric scale (0-10), with total scores ranging from 0 to 110. Higher scores indicate better overall recovery.

    Measured: Postoperative day 7

  4. Post-Discharge Opioid Use

    Participant-reported opioid use after hospital discharge, including total quantity of opioid medications used, collected via structured self-report and expressed as number of tablets consumed or morphine milligram equivalents (MME) when available.

    Measured: From hospital discharge through postoperative day 14

  5. Study Drug Adherence (Proportion of Prescribed Study Medication Doses Taken)

    Participant adherence to the assigned study medication regimen (suzetrigine or matching placebo), defined as the proportion of prescribed study medication doses taken during the postoperative period. Adherence will be calculated as the number of doses taken divided by the number of doses prescribed.

    For inpatient doses, adherence will be assessed using the electronic medication administration record (MAR). For postdischarge doses, adherence will be assessed using participant self-report with pill count verification when feasible.

    Measured: During hospitalization through postoperative day 7

  6. Adverse Events

    Occurrence of adverse events during the study period, assessed through clinical evaluation, electronic medical record review, and participant-reported follow-up assessments.

    Measured: From study drug initiation through postoperative day 14

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted16 Apr 2026
  2. Study startJun 2026 (estimated)
  3. Primary completionFeb 2028 (estimated)
  4. Study completionMay 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 4
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
Participants will be randomized in a 1:1 ratio to one of two parallel groups (suzetrigine or placebo) for the duration of the study. Randomization will be performed using a computer-generated allocation sequence with variable block sizes and allocation concealment.
Masking
Double blind
Who is masked
Participant, Care provider
Enrolment
90 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07534709
Sponsor's protocol ID
STUDY00008784
Acronym
SPARE
Status last verified
Apr 2026
First submitted
7 Apr 2026
Last updated
16 Apr 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Publications

  • Reed SE, Tan HS, Fuller ME, Krishnamoorthy V, Ohnuma T, Raghunathan K, Habib AS. Analgesia After Cesarean Delivery in the United States 2008-2018: A Retrospective Cohort Study. Anesth Analg. 2021 Dec 1;133(6):1550-1558. doi: 10.1213/ANE.0000000000005587.

    PubMed 34014182

  • Meyer MF, Broman AT, Gnadt SE, Sharma S, Antony KM. A standardized post-cesarean analgesia regimen reduces postpartum opioid use. J Matern Fetal Neonatal Med. 2022 Dec;35(25):8267-8274. doi: 10.1080/14767058.2021.1970132. Epub 2021 Aug 26.

    PubMed 34445918

  • Deussen AR, Ashwood P, Martis R, Stewart F, Grzeskowiak LE. Relief of pain due to uterine cramping/involution after birth. Cochrane Database Syst Rev. 2020 Oct 20;10(10):CD004908. doi: 10.1002/14651858.CD004908.pub3.

    PubMed 33078388

  • Veef E, Van de Velde M. Post-cesarean section analgesia. Best Pract Res Clin Anaesthesiol. 2022 May;36(1):83-88. doi: 10.1016/j.bpa.2022.02.006. Epub 2022 Apr 10.

    PubMed 35659962

  • Bertoch T, D'Aunno D, McCoun J, Solanki D, Taber L, Urban J, Oswald J, Swisher MW, Tian S, Miao X, Correll DJ, Negulescu P, Bozic C, Weiner SG. Suzetrigine, a Nonopioid Na V 1.8 Inhibitor for Treatment of Moderate-to-severe Acute Pain: Two Phase 3 Randomized Clinical Trials. Anesthesiology. 2025 Jun 1;142(6):1085-1099. doi: 10.1097/ALN.0000000000005460. Epub 2025 Mar 21.

    PubMed 40117446

  • Jones J, Correll DJ, Lechner SM, Jazic I, Miao X, Shaw D, Simard C, Osteen JD, Hare B, Beaton A, Bertoch T, Buvanendran A, Habib AS, Pizzi LJ, Pollak RA, Weiner SG, Bozic C, Negulescu P, White PF; VX21-548-101 and VX21-548-102 Trial Groups. Selective Inhibition of NaV1.8 with VX-548 for Acute Pain. N Engl J Med. 2023 Aug 3;389(5):393-405. doi: 10.1056/NEJMoa2209870.

    PubMed 37530822

  • Carvalho B, Butwick AJ. Postcesarean delivery analgesia. Best Pract Res Clin Anaesthesiol. 2017 Mar;31(1):69-79. doi: 10.1016/j.bpa.2017.01.003. Epub 2017 Jan 12.

    PubMed 28625307

  • Sultan P, Monks DT, Sharawi N, Bamber J, Panelli DM, Sauro KM, Shah PS, Muraca GM, Metcalfe A, Wood SL, Jago CA, Daly S, Blake LEA, Macones GA, Caughey AB, Wilson RD, Nelson G. Guidelines for postoperative care in cesarean delivery: Enhanced Recovery After Surgery Society recommendations (part 3)-2025 update. Am J Obstet Gynecol. 2026 Jan;233(6S):S184-S198. doi: 10.1016/j.ajog.2025.01.038. Epub 2025 Apr 28.

    PubMed 40335351

  • Finkelstein Y, Macdonald EM, Gonzalez A, Sivilotti MLA, Mamdani MM, Juurlink DN; Canadian Drug Safety And Effectiveness Research Network (CDSERN). Overdose Risk in Young Children of Women Prescribed Opioids. Pediatrics. 2017 Mar;139(3):e20162887. doi: 10.1542/peds.2016-2887. Epub 2017 Feb 20.

    PubMed 28219963

  • Osmundson SS, Schornack LA, Grasch JL, Zuckerwise LC, Young JL, Richardson MG. Postdischarge Opioid Use After Cesarean Delivery. Obstet Gynecol. 2017 Jul;130(1):36-41. doi: 10.1097/AOG.0000000000002095.

    PubMed 28594766

  • Peahl AF, Morgan DM, Dalton VK, Zivin K, Lai YL, Hu HM, Langen E, Low LK, Brummett CM, Waljee JF, Bauer ME. New persistent opioid use after acute opioid prescribing in pregnancy: a nationwide analysis. Am J Obstet Gynecol. 2020 Oct;223(4):566.e1-566.e13. doi: 10.1016/j.ajog.2020.03.020. Epub 2020 Mar 23.

    PubMed 32217114

  • Bateman BT, Franklin JM, Bykov K, Avorn J, Shrank WH, Brennan TA, Landon JE, Rathmell JP, Huybrechts KF, Fischer MA, Choudhry NK. Persistent opioid use following cesarean delivery: patterns and predictors among opioid-naive women. Am J Obstet Gynecol. 2016 Sep;215(3):353.e1-353.e18. doi: 10.1016/j.ajog.2016.03.016. Epub 2016 Mar 17.

    PubMed 26996986

  • ACOG Committee Opinion No. 742: Postpartum Pain Management. Obstet Gynecol. 2018 Jul;132(1):e35-e43. doi: 10.1097/AOG.0000000000002683.

    PubMed 29781876

  • Prabhu M, McQuaid-Hanson E, Hopp S, Burns SM, Leffert LR, Landau R, Lauffenburger JC, Choudhry NK, Kaimal A, Bateman BT. A Shared Decision-Making Intervention to Guide Opioid Prescribing After Cesarean Delivery. Obstet Gynecol. 2017 Jul;130(1):42-46. doi: 10.1097/AOG.0000000000002094.

    PubMed 28594762

  • Pharmacologic Stepwise Multimodal Approach for Postpartum Pain Management: ACOG Clinical Consensus No. 1. Obstet Gynecol. 2021 Sep 1;138(3):507-517. doi: 10.1097/AOG.0000000000004517.

    PubMed 34412076

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Suzetrigine in people with Cesarean Delivery and Cesarean Section, run by University of Texas at Austin at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: opening soon, as of the sponsor's last update on 16 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Chase Calvert, MD (512-771-0773, calvertchase@utexas.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Proportion of Participants Remaining Opioid-Free Through 72 Hours Postoperatively (time frame: From completion of surgery to 72 hours postoperatively). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07534709, which also lists 17 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Apr 2026.

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