Pan African Clinical Trials Registry
South African Medical Research Council, South African Cochrane Centre
PO Box 19070, Tygerberg, 7505, South Africa
Telephone: +27 21 938 0506 / +27 21 938 0834 Fax: +27 21 938 0836
Email: pactradmin@mrc.ac.za Website: pactr.samrc.ac.za
Trial no.: PACTR202604609702166 Date of Registration: 21/04/2026
Trial Status: Registered in accordance with WHO and ICMJE standards
TRIAL DESCRIPTION
Public title Lingual ondansetron for prevention of post-spinal hypotension in adult patients undergoing lower abdominal surgeries: A randomized controlled study
Official scientific title Lingual ondansetron for prevention of post-spinal hypotension in adult patients undergoing lower abdominal surgeries: A randomized controlled study
Brief summary describing the background and objectives of the trial Spinal anesthesia is the most common anesthesia technique for cesarean section and general surgical procedures on the lower limbs, perineum and lower abdomen. This technique is technically easy, providing not only fast intraoperative anesthesia with less respiratory impact, but also better pain control and favoring a rapid recovery. Arterial hypotension can lead to a reduction in blood flow and cardiac output, resulting in a state of systemic hypoperfusion. Following spinal anesthesia, hypotension results mainly from a decrease in systemic vascular resistance secondary to a blockage of sympathetic fibers and an increase in vagal tone. The reduction in venous return can trigger the Von Bezold-Jarisch reflex, mediated by serotonin receptors (subtype 5-HT3), resulting in increased efferent vagal signaling and bradycardia, ultimately exacerbating hypotension . After verification that serotonin can induce BJR reflex in animals and can causes bradycardia and hypotension in 1990s, researchers started to evaluate the effect of serotonin antagonists (especially ondansetron) to decrease BJR reflex in human being. Regarding the prevention and treatment of post spinal hypotension, the international consensus guideline recommends that the systolic arterial pressure (SAP) should be maintained at ≥ 90% and to avoid decreasing SBP below 80% of the baseline. Systolic arterial pressure values < 80% should be treated expeditiously. Even though fluids, ephedrine, or lower leg compression can reduce the incidence of hypotension, no single method completely prevents it or none can eliminate the need to treat hypotension. Bradycardia is observed up to 13% in non-obstetric patients during spinal anesthesia. If corrective measures taken immediately bradycardia may not cause significant consequences. However severe bradycardia can rapidly progress to asystole and bradycardia induced by spinal anesthesia should therefore always be considered warning sign of an impending hemodynamic instability. While ondansetron shows promising effects in some studies, it fails in others. The controversy is still ongoing and effectiveness of ondansetron in preventing spinal induced hypotension is not proven. Furthermore, there are so many literatures that recommend further study with different doses before applying ondansetron as routine measure for prevention of (PSH) .These controversies and recommendations initiate to conduct the study. The use of Ondansetron pre-operatively also has many secondary advantages such as decrease incidence of nausea, vomiting; shivering and used as treatment of opioid induced pruritus. If ondansetron is effective in preventing PSH, administering it as a prophylaxis can be considered as hitting two birds with a single stone. Sublingual ondansetron is easy to administer and quick onset of drug action is possible as the ondansetron films are taken through the sublingual route. Since the sublingual mucosa is relatively permeable because of thin membrane and is highly perfused, rapid drug absorption and instant bioavailability is possible and this leads to quick-onset of drug action. Since the drug is directly absorbed into the systemic circulation, degradation in the gastrointestinal (GI) tract and first pass effect is avoided . The primary objective of this randomized controlled study was to investigate the efficacy of sublingual 8 mg ondansetron film administered 30min before spinal anesthesia in adult patients undergoing lower abdominal surgeries in preventing spinal anesthesia-induced hypotension.
Type of trial RCT
Acronym (If the trial has an acronym then please provide)
Disease(s) or condition(s) being studied Anaesthesia,Cardiology,Circulatory System
Sub-Disease(s) or condition(s) being studied
Purpose of the trial Prevention
Anticipated trial start date 15/04/2026
Actual trial start date 22/04/2026
Anticipated date of last follow up 01/10/2026
Actual Last follow-up date 01/10/2026
Anticipated target sample size (number of participants) 90
Actual target sample size (number of participants)
Recruitment status Recruiting
Publication URL
Secondary Ids Issuing authority/Trial register
STUDY DESIGN
Intervention assignment Allocation to intervention If randomised, describe how the allocation sequence was generated Describe how the allocation sequence/code was concealed from the person allocating the participants to the intervention arms Masking If masking / blinding was used
Parallel: different groups receive different interventions at same time during study Randomised Simple randomization using a randomization table created by a computer software program Sealed opaque envelopes Masking/blinding used Care giver/Provider,Outcome Assessors,Participants
INTERVENTIONS
Intervention type Intervention name Dose Duration Intervention description Group size Nature of control
Control Group A placebo Patients in the control group will receive a placebo which will be a size and shape as ondansetron film. 30 minutes before spinal anesthesia Patients in the control group will receive a placebo which will be a size and shape as ondansetron film. 45 Placebo
Experimental Group ondansetron Patients in ondansetron group will receive a single dose of sublingual ondansetron 8 mg film, 30 minutes before spinal anesthesia. 30 minutes before spinal anesthesia Patients in ondansetron group will receive a single dose of sublingual ondansetron 8 mg film, 30 minutes before spinal anesthesia. 45
ELIGIBILITY CRITERIA
List inclusion criteria List exclusion criteria Age Category Minimum age Maximum age Gender
1. Patients of both sexes aged 18 to 45 undergoing unilateral lower abdominal surgeries using spinal anesthesia. 2. Height from 160 cm to 180 cm. 3. American Society of Anesthesiologist physical status I, II . 4. Body mass index less than 30 kg/m². 1. Patients who refuse to participate in the study 2. Elevated BP (>160/100 mm Hg) 3. Failed spinal anesthesia 4. Patients with known cardiovascular disease 5. Patients with known cerebrovascular disease 6. Patients with known neurological, neurodegenerative or psychiatric disease 7. Patients with known liver cell failure 8. Clinical history of diabetes. 9. Contraindication to spinal anesthesia e.g., coagulopathy. 10. Patients with known allergy to ondansetron. Adult: 18 Year(s)-44 Year(s),Middle Aged: 45 Year(s)-64 Year(s) 18 Year(s) 50 Year(s) Both
ETHICS APPROVAL
Has the study received appropriate ethics committee approval Date the study will be submitted for approval Date of approval Name of the ethics committee
Yes 01/03/2026 Mansoura Faculty of Medicine Institutional Research Board
Ethics Committee Address
Street address City Postal code Country
2 El-Gomhouria Street Mansoura 35516 Egypt
OUTCOMES
Type of outcome Outcome Timepoint(s) at which outcome measured
Primary Outcome The primary outcome will be the incidence of hypotensive episodes within I hour from the start of spinal anesthesia. within I hour from the start of spinal anesthesia
Secondary Outcome The secondary outcomes will be the number of hypotensive episodes, post spinal bradycardia episodes and MAP and HR measured at 5, 10, 15, 20, 30, 45, and 60 min after spinal anesthesia, within I hour from the start of spinal anesthesia
RECRUITMENT CENTRES
Name of recruitment centre Street address City Postal code Country
Mansoura University Hospital 2 El-Gomhouria Street Mansoura 35516 Egypt
FUNDING SOURCES
Name of source Street address City Postal code Country
Mansoura University Hospital 2 El-Gomhouria Street Mansoura 35516 Egypt
SPONSORS
Sponsor level Name Street address City Postal code Country Nature of sponsor
Primary Sponsor Mansoura University Hospital 2 El-Gomhouria Street Mansoura 35516 Egypt Hospital
COLLABORATORS
Name Street address City Postal code Country
CONTACT PEOPLE
Role Name Email Phone Street address
Principal Investigator Ibrahim Abdelbaser ibraheem2005@mans.edu.eg +201004976825 2 El-Gomhouria Street
City Postal code Country Position/Affiliation
Mansoura 35516 Egypt Department of Anesthesia and Surgical Intensive Care Faculty of Medicine Mansoura University Mansoura Egypt
Role Name Email Phone Street address
Public Enquiries Nabil Abdelraouf nabil-abdelraouf@yahoo.com +2001001538648 2 El-Gomhouria Street
City Postal code Country Position/Affiliation
Mansoura 35516 Egypt Department of Anesthesia and Surgical Intensive Care Faculty of Medicine Mansoura University Mansoura Egypt Phone
Role Name Email Phone Street address
Scientific Enquiries Ibrahim Abdelbaser ibraheem2005@mans.edu.eg +201004676825 2 El-Gomhouria Street
City Postal code Country Position/Affiliation
Mansoura 35516 Egypt Department of Anesthesia and Surgical Intensive Care Faculty of Medicine Mansoura University Mansoura Egypt
REPORTING
Share IPD Description Additional Document Types Sharing Time Frame Key Access Criteria
Yes All of the individual participant data collected during the trial, after deidentification Informed Consent Form,Statistical Analysis Plan,Study Protocol Immediately following publication, no end data Any one who want to access the data
URL Results Available Results Summary Result Posting Date First Journal Publication Date
No
Result Upload 1: Result Upload 2: Result Upload 3: Result Upload 4: Result Upload 5:
Result URL Hyperlinks Link To Protocol
Result URL Hyperlinks
Changes to trial information
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Trial description 30/03/2026 according to admin recommendatins Our hypothesis is that the use of sublingual 8 mg ondansetron film 30 min before spinal anesthesia in adult patients undergoing lower abdominal surgeries will be associated with less spinal anesthesia induced hypotension and less intraoperative nausea and vomiting. Spinal anesthesia is the most common anesthesia technique for cesarean section and general surgical procedures on the lower limbs, perineum and lower abdomen. This technique is technically easy, providing not only fast intraoperative anesthesia with less respiratory impact, but also better pain control and favoring a rapid recovery. Arterial hypotension can lead to a reduction in blood flow and cardiac output, resulting in a state of systemic hypoperfusion. Following spinal anesthesia, hypotension results mainly from a decrease in systemic vascular resistance secondary to a blockage of sympathetic fibers and an increase in vagal tone. The reduction in venous return can trigger the Von Bezold-Jarisch reflex, mediated by serotonin receptors (subtype 5-HT3), resulting in increased efferent vagal signaling and bradycardia, ultimately exacerbating hypotension . After verification that serotonin can induce BJR reflex in animals and can causes bradycardia and hypotension in 1990s, researchers started to evaluate the effect of serotonin antagonists (especially ondansetron) to decrease BJR reflex in human being. Regarding the prevention and treatment of post spinal hypotension, the international consensus guideline recommends that the systolic arterial pressure (SAP) should be maintained at ≥ 90% and to avoid decreasing SBP below 80% of the baseline. Systolic arterial pressure values < 80% should be treated expeditiously. Even though fluids, ephedrine, or lower leg compression can reduce the incidence of hypotension, no single method completely prevents it or none can eliminate the need to treat hypotension. Bradycardia is observed up to 13% in non-obstetric patients during spinal anesthesia. If corrective measures taken immediately bradycardia may not cause significant consequences. However severe bradycardia can rapidly progress to asystole and bradycardia induced by spinal anesthesia should therefore always be considered warning sign of an impending hemodynamic instability. While ondansetron shows promising effects in some studies, it fails in others. The controversy is still ongoing and effectiveness of ondansetron in preventing spinal induced hypotension is not proven. Furthermore, there are so many literatures that recommend further study with different doses before applying ondansetron as routine measure for prevention of (PSH) .These controversies and recommendations initiate to conduct the study. The use of Ondansetron pre-operatively also has many secondary advantages such as decrease incidence of nausea, vomiting; shivering and used as treatment of opioid induced pruritus. If ondansetron is effective in preventing PSH, administering it as a prophylaxis can be considered as hitting two birds with a single stone. Sublingual ondansetron is easy to administer and quick onset of drug action is possible as the ondansetron films are taken through the sublingual route. Since the sublingual mucosa is relatively permeable because of thin membrane and is highly perfused, rapid drug absorption and instant bioavailability is possible and this leads to quick-onset of drug action. Since the drug is directly absorbed into the systemic circulation, degradation in the gastrointestinal (GI) tract and first pass effect is avoided . The primary objective of this randomized controlled study was to investigate the efficacy of sublingual 8 mg ondansetron film administered 30min before spinal anesthesia in adult patients undergoing lower abdominal surgeries in preventing spinal anesthesia-induced hypotension.
Section Name Field Name Date Reason Old Value Updated Value
Eligibility Age group 21/04/2026 PACTR Admin Adolescent: 13 Year(s)-17 Year(s), Adult: 18 Year(s)-44 Year(s), Middle Aged: 45 Year(s)-64 Year(s) Adult: 18 Year(s)-44 Year(s), Middle Aged: 45 Year(s)-64 Year(s)
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 23/03/2026 According to your recommendations Control Group, Control , Patients in the control group (placebo group) will receive a placebo which will be a size and shape as ondansetron film., 30 minutes before spinal anesthesia, Patients in the control group (placebo group) will receive a placebo which will be a size and shape as ondansetron film., 45, Placebo
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 30/03/2026 According to admin recommendation Control Group, Control , Patients in the control group (placebo group) will receive a placebo which will be a size and shape as ondansetron film., 30 minutes before spinal anesthesia, Patients in the control group (placebo group) will receive a placebo which will be a size and shape as ondansetron film., 45, Placebo Control Group, A placebo, Patients in the control group will receive a placebo which will be a size and shape as ondansetron film., 30 minutes before spinal anesthesia, Patients in the control group will receive a placebo which will be a size and shape as ondansetron film., 45, Placebo
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 23/03/2026 According to your recommendations Experimental Group, ondansetron group , Patients in ondansetron group will receive a single dose of sublingual ondansetron 8 mg film, 30 minutes before spinal anesthesia., 30 minutes before spinal anesthesia, Patients in ondansetron group will receive a single dose of sublingual ondansetron 8 mg film, 30 minutes before spinal anesthesia., 45, Experimental Group, ondansetron , Patients in ondansetron group will receive a single dose of sublingual ondansetron 8 mg film, 30 minutes before spinal anesthesia., 30 minutes before spinal anesthesia, Patients in ondansetron group will receive a single dose of sublingual ondansetron 8 mg film, 30 minutes before spinal anesthesia., 45,