HypotensionPhase 4NCT07886151
Prophylactic Ondansetron for Preventing Spinal Anesthesia-Induced Hypotension in Elective Cesarean Section
A Phase 4 study testing Ondansetron in people with Hypotension and Spinal Anesthesia, run by Saglik Bilimleri Universitesi Gazi Yasargil Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
Spinal anesthesia is the preferred technique for elective cesarean section, but it frequently causes maternal hypotension due to sympathetic blockade and the Bezold-Jarisch reflex, which can threaten both mother and baby. Read more about this study
- Who is it for?
- Ages 18 to 45 years, women only
- Conditions the study is for
- Hypotension, Spinal Anesthesia, Cesarean Section
- What is being tested?
- Ondansetron
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 96 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 2 Feb 2026to 10 Jul 2026
- Phase
- Phase 4
- Are there results?
- None posted in the registry
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 to 45 years
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- Age 18-45 years
- Term pregnancy
- Singleton pregnancy
- Scheduled for elective cesarean section
- American Society of Anesthesiologists (ASA) physical status II
- Accepting spinal anesthesia as the anesthetic technique
- Written informed consent
Who cannot join
- Emergency cesarean section
- ASA physical status III or higher
- Allergy to ondansetron or other 5-HT3 receptor antagonists
- Multiple pregnancy
- Preeclampsia, eclampsia or HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome
- Active smoking
Show all 9Show fewer
- Pre-existing serious cardiac disease or history of QT prolongation
- Need for intraoperative sedation or conversion to general anesthesia
- Surgery lasting longer than one hour
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Saglik Bilimleri Universitesi Gazi Yasargil Training and Research Hospital
Diyarbakır, 21070
About this study
Official title: Efficacy of Prophylactic Ondansetron in Preventing Hypotension After Spinal Anesthesia in Elective Cesarean Sections: A Prospective Randomized Controlled Trial
Spinal anesthesia is the preferred technique for elective cesarean section, but it frequently causes maternal hypotension due to sympathetic blockade and the Bezold-Jarisch reflex, which can threaten both mother and baby. Ondansetron, a serotonin 5-HT3 receptor antagonist commonly used to prevent nausea and vomiting, may attenuate this reflex.
The purpose of this prospective, randomized, controlled, single-blind study is to evaluate whether a single prophylactic intravenous dose of ondansetron (4 mg) given before spinal anesthesia reduces the incidence of hypotension in women undergoing elective cesarean section. Vasopressor (ephedrine) requirement, heart rate, postspinal shivering, intraoperative nausea and vomiting, and newborn Apgar scores are also compared between the ondansetron and control (saline) groups.
Read the detailed description
Design: Prospective, randomized, controlled, single-blind (participant), parallel-group, single-center trial conducted in the operating rooms of University of Health Sciences Gazi Yasargil Training and Research Hospital, Diyarbakir, Turkey.
Participants: Term pregnant women aged 18-45 years, ASA physical status II, with a singleton pregnancy, scheduled for elective cesarean section under spinal anesthesia.
Randomization: Eligible participants are allocated 1:1 by computer-generated simple randomization to the ondansetron group or the control group. The study solutions are identical in appearance, so participants are unaware of their group allocation.
Interventions: Ten minutes before spinal anesthesia, the ondansetron group receives 4 mg ondansetron in 100 mL of 0.9% sodium chloride warmed to 37°C as an intravenous infusion; the control group receives 100 mL of 0.9% sodium chloride warmed to 37°C under the same conditions.
Anesthesia protocol: Operating room temperature is maintained at 20±2°C. Spinal anesthesia is performed in the sitting position at the L4-L5 interspace with a 26G sharp-tip spinal needle using 0.5% hyperbaric bupivacaine, dosed according to the patient's height and weight. Simultaneously with spinal anesthesia, 20 mL/kg crystalloid (Ringer's lactate or 0.9% sodium chloride) is given as a rapid co-load infusion. Patients are positioned supine with approximately 15° left lateral tilt. After delivery, oxytocin is given as a 3 IU IV bolus followed by a 3 IU/hour infusion. The highest sensory block level is assessed by pin-prick.
Hemodynamic management: Hypotension is defined as a mean arterial pressure (MAP) below 65 mmHg or a decrease of 20% or more from baseline at any measurement time. Hypotension is treated with 10 mg IV ephedrine, repeated as needed. Bradycardia (heart rate below 50 beats/min) with hypotension is treated with 0.5 mg IV atropine. Intraoperative nausea or vomiting is treated with 4 mg IV ondansetron as a rescue antiemetic regardless of group.
Monitoring: Systolic, diastolic and mean arterial pressure, heart rate and SpO2 are recorded at baseline (before spinal anesthesia), at 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia, and postoperatively. Nausea-vomiting episodes, postspinal shivering (Crossley and Mahajan five-point scale; grade 2 or higher considered clinically significant), total ephedrine and atropine use, sensory and motor block levels, and 1- and 5-minute Apgar scores are recorded.
Withdrawal criteria: Need for intraoperative sedation, conversion to general anesthesia due to failed spinal anesthesia, serious drug reactions, other technical failures (including prolonged surgery), data loss, or participant withdrawal.
Sample size: Power analysis (G*Power; alpha 0.05, power 80%) indicated a minimum of 47 participants per group (94 in total); allowing for dropouts, 102 participants were planned.
Statistical analysis: Group comparisons are performed using Welch's t-test, Mann-Whitney U test, Pearson chi-square or Fisher's exact test as appropriate; changes in MAP over time are analyzed with repeated-measures ANOVA. A p value < 0.05 is considered statistically significant.
- Conditions
- Hypotension, Spinal Anesthesia, Cesarean Section
- Being tested
- Ondansetron, Placebo (0.9% Sodium Chloride)
- Keywords
- Ondansetron, Spinal anesthesia-induced hypotension, Bezold-Jarisch reflex, Shivering, Ephedrine, Obstetric anesthesia
- Medical subject headings
- Hypotension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OndansetronDrug
A single dose of 4 mg ondansetron diluted in 100 mL of 0.9% sodium chloride warmed to 37°C, administered as an intravenous infusion starting 10 minutes before spinal anesthesia.
Placebo (0.9% Sodium Chloride)Drug
100 mL of 0.9% sodium chloride warmed to 37°C, identical in appearance to the study solution, administered as an intravenous infusion starting 10 minutes before spinal anesthesia.
| Study group | Role | What they receive |
|---|---|---|
| Ondansetron Group | Experimental | Participants receive 4 mg intravenous ondansetron in 100 mL of warmed (37°C) 0.9% sodium chloride, infused starting 10 minutes before spinal anesthesia with 0.5% hyperbaric bupivacaine, plus 20 mL/kg crystalloid co-load. Receives: Drug: Ondansetron |
| Control Group | Placebo comparator | Participants receive 100 mL of warmed (37°C) 0.9% sodium chloride, identical in appearance, infused starting 10 minutes before spinal anesthesia with 0.5% hyperbaric bupivacaine, plus 20 mL/kg crystalloid co-load. Receives: Drug: Placebo (0.9% Sodium Chloride) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of Spinal Anesthesia-Induced Hypotension
Percentage of participants who develop hypotension, defined as a mean arterial pressure (MAP) below 65 mmHg or a decrease of 20% or more from baseline MAP at any measurement time after spinal anesthesia. MAP is recorded at baseline and at 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia.
Measured: From intrathecal injection until the end of surgery (up to 60 minutes)
Secondary outcomes (6)
Total Ephedrine Consumption
Total dose (mg) of intravenous ephedrine administered to treat hypotension (10 mg boluses, repeated as needed).
Measured: From intrathecal injection until the end of surgery (up to 60 minutes)
Mean Arterial Pressure Over Time
Mean arterial pressure (mmHg) measured non-invasively at baseline (before spinal anesthesia) and at 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia, and postoperatively.
Measured: Baseline and 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia, and postoperatively
Heart Rate and Incidence of Bradycardia
Heart rate (beats/min) at the same time points as blood pressure; bradycardia is defined as heart rate below 50 beats/min, and the number of participants requiring 0.5 mg IV atropine is recorded.
Measured: Baseline and 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia, and postoperatively
Incidence of Postspinal Shivering
Percentage of participants with clinically significant shivering, defined as grade 2 or higher on the five-point Crossley and Mahajan shivering scale.
Measured: From intrathecal injection until the end of surgery (up to 60 minutes)
Incidence of Intraoperative Nausea and Vomiting
Percentage of participants experiencing at least one episode of nausea or vomiting during surgery.
Measured: From intrathecal injection until the end of surgery (up to 60 minutes)
Neonatal Apgar Scores
Apgar scores of the newborn at 1 and 5 minutes after delivery (scale 0-10; higher scores indicate better neonatal condition).
Measured: 1 and 5 minutes after delivery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Oct 2026
- Study start2 Feb 2026
- Primary completion10 Jul 2026
- Study completion10 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HypotensionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants are randomized 1:1 to receive either prophylactic intravenous ondansetron or an equal volume of 0.9% sodium chloride (control) 10 minutes before spinal anesthesia.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 96 participants (actual)
Sponsor and investigators
- Lead sponsor
- Saglik Bilimleri Universitesi Gazi Yasargil Training and Research Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Emrullah ACAR, Saglik Bilimleri Universitesi Gazi Yasargil Training and Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07886151
- Sponsor's protocol ID
- 341761
- Other IDs
- 96
- Status last verified
- Oct 2026
- First submitted
- 14 Oct 2026
- Last updated
- 21 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared publicly; anonymized data may be made available by the investigators upon reasonable request.
Study at a glance
From the registry record, last updated by the sponsor on 21 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacy of Prophylactic Ondansetron in Preventing Hypotension After Spinal Anesthesia in Elective Cesarean Sections: A Prospective Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07886151
- Acronym / sponsor ID
- 341761
- Conditions
- Hypotension, Spinal Anesthesia, Cesarean Section
- Keywords
- Ondansetron, Spinal anesthesia-induced hypotension, Bezold-Jarisch reflex, Shivering, Ephedrine, Obstetric anesthesia
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 96 participants (actual)
- Lead sponsor
- Saglik Bilimleri Universitesi Gazi Yasargil Training and Research HospitalUniversity, hospital or other
- Study start
- 2 Feb 2026 (actual)
- Primary completion
- 10 Jul 2026 (actual)
- Study completion
- 10 Jul 2026 (actual)
- First posted
- 21 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Spinal anesthesia is the preferred technique for elective cesarean section, but it frequently causes maternal hypotension due to sympathetic blockade and the Bezold-Jarisch reflex, which can threaten both mother and baby. Ondansetron, a serotonin 5-HT3 receptor antagonist commonly used to prevent nausea and vomiting, may attenuate this reflex.
The purpose of this prospective, randomized, controlled, single-blind study is to evaluate whether a single prophylactic intravenous dose of ondansetron (4 mg) given before spinal anesthesia reduces the incidence of hypotension in women undergoing elective cesarean section. Vasopressor (ephedrine) requirement, heart rate, postspinal shivering, intraoperative nausea and vomiting, and newborn Apgar scores are also compared between the ondansetron and control (saline) groups.
Detailed description
Design: Prospective, randomized, controlled, single-blind (participant), parallel-group, single-center trial conducted in the operating rooms of University of Health Sciences Gazi Yasargil Training and Research Hospital, Diyarbakir, Turkey.
Participants: Term pregnant women aged 18-45 years, ASA physical status II, with a singleton pregnancy, scheduled for elective cesarean section under spinal anesthesia.
Randomization: Eligible participants are allocated 1:1 by computer-generated simple randomization to the ondansetron group or the control group. The study solutions are identical in appearance, so participants are unaware of their group allocation.
Interventions: Ten minutes before spinal anesthesia, the ondansetron group receives 4 mg ondansetron in 100 mL of 0.9% sodium chloride warmed to 37°C as an intravenous infusion; the control group receives 100 mL of 0.9% sodium chloride warmed to 37°C under the same conditions.
Anesthesia protocol: Operating room temperature is maintained at 20±2°C. Spinal anesthesia is performed in the sitting position at the L4-L5 interspace with a 26G sharp-tip spinal needle using 0.5% hyperbaric bupivacaine, dosed according to the patient's height and weight. Simultaneously with spinal anesthesia, 20 mL/kg crystalloid (Ringer's lactate or 0.9% sodium chloride) is given as a rapid co-load infusion. Patients are positioned supine with approximately 15° left lateral tilt. After delivery, oxytocin is given as a 3 IU IV bolus followed by a 3 IU/hour infusion. The highest sensory block level is assessed by pin-prick.
Hemodynamic management: Hypotension is defined as a mean arterial pressure (MAP) below 65 mmHg or a decrease of 20% or more from baseline at any measurement time. Hypotension is treated with 10 mg IV ephedrine, repeated as needed. Bradycardia (heart rate below 50 beats/min) with hypotension is treated with 0.5 mg IV atropine. Intraoperative nausea or vomiting is treated with 4 mg IV ondansetron as a rescue antiemetic regardless of group.
Monitoring: Systolic, diastolic and mean arterial pressure, heart rate and SpO2 are recorded at baseline (before spinal anesthesia), at 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia, and postoperatively. Nausea-vomiting episodes, postspinal shivering (Crossley and Mahajan five-point scale; grade 2 or higher considered clinically significant), total ephedrine and atropine use, sensory and motor block levels, and 1- and 5-minute Apgar scores are recorded.
Withdrawal criteria: Need for intraoperative sedation, conversion to general anesthesia due to failed spinal anesthesia, serious drug reactions, other technical failures (including prolonged surgery), data loss, or participant withdrawal.
Sample size: Power analysis (G*Power; alpha 0.05, power 80%) indicated a minimum of 47 participants per group (94 in total); allowing for dropouts, 102 participants were planned.
Statistical analysis: Group comparisons are performed using Welch's t-test, Mann-Whitney U test, Pearson chi-square or Fisher's exact test as appropriate; changes in MAP over time are analyzed with repeated-measures ANOVA. A p value < 0.05 is considered statistically significant.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- Participants are randomized 1:1 to receive either prophylactic intravenous ondansetron or an equal volume of 0.9% sodium chloride (control) 10 minutes before spinal anesthesia.
| Arm | Type | Receives |
|---|---|---|
| Ondansetron Group | Experimental | Drug: OndansetronParticipants receive 4 mg intravenous ondansetron in 100 mL of warmed (37°C) 0.9% sodium chloride, infused starting 10 minutes before spinal anesthesia with 0.5% hyperbaric bupivacaine, plus 20 mL/kg crystalloid co-load. |
| Control Group | Placebo comparator | Drug: Placebo (0.9% Sodium Chloride)Participants receive 100 mL of warmed (37°C) 0.9% sodium chloride, identical in appearance, infused starting 10 minutes before spinal anesthesia with 0.5% hyperbaric bupivacaine, plus 20 mL/kg crystalloid co-load. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Age 18-45 years
- Term pregnancy
- Singleton pregnancy
- Scheduled for elective cesarean section
- American Society of Anesthesiologists (ASA) physical status II
Key exclusion criteria (9 listed)
- Emergency cesarean section
- ASA physical status III or higher
- Allergy to ondansetron or other 5-HT3 receptor antagonists
- Multiple pregnancy
- Preeclampsia, eclampsia or HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| OndansetronA single dose of 4 mg ondansetron diluted in 100 mL of 0.9% sodium chloride warmed to 37°C, administered as an intravenous infusion starting 10 minutes before spinal anesthesia. | Drug | Ondansetron Group |
| Placebo (0.9% Sodium Chloride)100 mL of 0.9% sodium chloride warmed to 37°C, identical in appearance to the study solution, administered as an intravenous infusion starting 10 minutes before spinal anesthesia. | Drug | Control Group |
Primary outcome
Incidence of Spinal Anesthesia-Induced Hypotension
Time frame: From intrathecal injection until the end of surgery (up to 60 minutes)
Percentage of participants who develop hypotension, defined as a mean arterial pressure (MAP) below 65 mmHg or a decrease of 20% or more from baseline MAP at any measurement time after spinal anesthesia. MAP is recorded at baseline and at 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia.
6 secondary outcomes
Total Ephedrine Consumption
Time frame: From intrathecal injection until the end of surgery (up to 60 minutes)
Mean Arterial Pressure Over Time
Time frame: Baseline and 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia, and postoperatively
Heart Rate and Incidence of Bradycardia
Time frame: Baseline and 3, 6, 9, 12, 15, 20, 25, 30 and 35 minutes after spinal anesthesia, and postoperatively
Incidence of Postspinal Shivering
Time frame: From intrathecal injection until the end of surgery (up to 60 minutes)
Incidence of Intraoperative Nausea and Vomiting
Time frame: From intrathecal injection until the end of surgery (up to 60 minutes)
Neonatal Apgar Scores
Time frame: 1 and 5 minutes after delivery
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Oct 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared publicly; anonymized data may be made available by the investigators upon reasonable request.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Ondansetron in people with Hypotension and Spinal Anesthesia, run by Saglik Bilimleri Universitesi Gazi Yasargil Training and Research Hospital at 1 site in Turkey (Türkiye).
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 7 inclusion and 9 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: finished, as of the sponsor's last update on 21 Oct 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 Turkey (Türkiye). 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. Some participants in this study may receive a placebo. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of Spinal Anesthesia-Induced Hypotension (time frame: From intrathecal injection until the end of surgery (up to 60 minutes)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 21 Oct 2026.