A Phase 2/3 interventional study of ondansetron and placebo in Hypotension and Pregnancy, sponsored by University of Virginia. Completed at 1 site in United States. Open to female participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2022-03-24.
Sponsored by University of Virginia · Phase 2/3, Interventional, and Prevention
The investigators hypothesize that given prophylactically, intravenous ondansetron will attenuate the drop in blood pressure and heart rate frequently seen after spinal anesthesia.
Eighty-six American Society of Anesthesiologists (ASA) physical status I or II in preoperative patient assessment, parturients age of 18 to 45 years scheduled to undergo elective caesarean section will be enrolled.
Patients will be randomized to 2 groups: the ondansetron group, receiving 8 mg intravenous ondansetron diluted in 10 mL of saline; or the placebo group, who were administered 10 mL of saline given 5 minutes prior to performing the spinal anesthetic. Investigational Pharmacy will randomize and dispense study drug.
Baseline measurements of vital signs will be taken. Otherwise standard management will then be used:
The sensory level of anesthesia will be assessed in the standard fashion every five minutes using ice. The motor component will tested using the Bromage scale for spinal anesthesia (0, no paralysis; 1, inability to lift the thigh [only knee/feet]; 2, inability to flex the knee [only feet]; 3, inability to move any joint in the legs).
Over the last 30 years, regional anesthesia has emerged as the method of choice for elective caesarean section because it avoids risks involved in managing the airway of the parturient and has the added significant benefit of mother being awake for the birth of her child. Indeed, this changing practice patterns is thought to have lead to a significant drop in anesthesia related maternal morbidity and mortality.
At the same time, regional anesthesia is associated with both minor and significant risk.
Most common among these effects is hypotension and bradycardia, occurring in 33% and 13% of cases, respectively. In the pregnant patient, supine positioning required for surgery is associated hypotension due to aortocaval compression by the gravid uterus in 8% of patients, even without spinal anesthesia. During caesarean section, the combination of these factors can lead to hypotension include decreased placental blood flow, impaired fetal oxygenation and fetal acidosis. Maternal symptoms of low blood pressures include nausea, vomiting, dizziness, and decreased consciousness. This situation has lead to dozens of publications seeking to prevent or minimize the hypotensive response.
Hypotension after a spinal is initially due to a blockade of sympathetic fibers leading to a drop in systemic vascular resistance. Spinal-induced bradycardia is multifactorial but is in part due to the Bezold-Jarisch Reflex (BJR). This reflex is mediated by serotonin receptors within the wall of the ventricle in response to systemic hypotension. These receptors, the 5HT3 subtype, cause an increase efferent vagal signaling when bound by serotonin released during hypovolemic states, clinically leading to bradycardia and further hypotension.
Ondansetron, a widely used anti-emetic and serotonin antagonist, has been safely used to blunt the BJR, resulting in less bradycardia and hypotension first in animals and later in humans undergoing spinal anesthesia. ,
Use During Pregnancy:
The FDA labels ondansetron as a class B. Studies in pregnant rats and rabbits at doses up to 70 times higher than clinically used doses revealed no evidence of impaired fertility or harm to the fetus due to ondansetron. There are, however, few prospective studies in pregnant women. Nevertheless, the drug is widely used has a long safety history for use in pregnancy and during anesthesia for caesarean section.
1,003 studies on the registry are indexed under Hypotension; 173 are open to participants now.
This study's enrollment of 68 is below the median of 80 across 675 interventional studies indexed under Hypotension.
Browse Hypotension studies →University of Virginia is the lead sponsor of 653 studies on the registry; 134 are open to participants now.
Of its 60 completed or terminated interventional studies of FDA-regulated products, 41 (68%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Contraindications to spinal anesthetic
ondansetron 8 mg IV will be administered prior to placement of the spinal anesthesia
Drug: ondansetron
Ondansetron 8 mg IV or Placebo will be administered prior to placement of the spinal anesthestic
Drug: placebo
Ondansetron 8mg IV or placebo will be administered prior to placement of the spinal anesthetic
Also known as: epidural
placebo or ondansetron 8mg IV will be administered prior to placement of the spinal anesthetic
Also known as: epidural
Number of Participants with Adverse Events as a Measure of Safety and Tolerability"
hypotension \& bradycardia will be recorded from the placement of the spinal through the end of surgical c-section
Time frame: day 1
dosage of vasopressors administered
vasopressors administered during surgery
Time frame: day one
number of episodes of nausea
Time frame: 24 hours after surgery
occurrence & intensity of itching
Time frame: 24 hours after surgery
pain scores reported by the patient
Time frame: 24 hours after surgery
dosage of anticholinergics administered
Time frame: 24 hours after surgery
This study is completed, as verified in Mar 2022. You cannot join it, but the record below documents what was studied.
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University of Virginia