Ondansetron Use for Preventing Pruritus in Patients Undergoing Cesarean Section

Inclusion Criteria:

1. American Society of Anesthesiologists (ASA) physical status 1-3
2. Adult parturient (18 -50 years of age) scheduled to undergo elective cesarean delivery under spinal anesthesia
3. Patients must be willing and cognitively able to give written informed study consent

Exclusion Criteria:

1. Patients with an ASA physiological assessment greater than grade 3
2. Allergies to local anesthetics, opioids, or ondansetron
3. Coagulopathies precluding provision of spinal anesthesia
4. Pre-eclampsia with severe features
5. Eclampsia
6. Pre-intrathecal pruritus
7. Psychiatric or language deficiencies affecting assessment of pain
8. Insufficient understanding of the pain scoring system
9. Patients who receive any other regional anesthesia techniques
10. Patients on higher than a 100mg of daily morphine equivalent
11. Cardiac issues that would preclude spinal anesthesia (Congestive heart failure, Mitral or Aortic valve pathology.
12. Confounding neural issues that would preclude spinal anesthesia.
13. Coadministration of drugs that would potentially interact with ondansetron. Including Apomorphine, Phenytoin, Carbamazepine, Rifampicin, Tramadol and Chemotherapy drugs.
14. Coadministration of drugs that would potentially prolong QTc interval. Including Antiarrhythmic, Antidepressants, Antipsychotics, and the following list of medications.

    a. Levofloxacin, Ciprofloxacin, Gatifloxacin, Moxifloxacin, Clarithromycin, Erythromycin, Ketoconazole, Itraconazole, Cisapride, Sumatriptan, Zolmitriptan, Arsenic, Dolasetron, Methadone
15. Coadministration of drugs that would potentially lead to the development of serotonin syndrome. Including the following:

    a. Selective serotonin reuptake inhibitors, Serotonin and norepinephrine reuptake inhibitors, antidepressants, carbamazepine , valproic acid, triptans, Chronic pain medications prior to procedure (Fentanyl, Hydrocodone, Meperidine, Oxycodone, tramadol),Lithium, dextromethorphan, Linezolid and Ritonavir
16. Patients having the following

    1. Patients known to have hypersensitivity (e.g., anaphylaxis) to ondansetron or any components of the formulation
    2. Concomitant use of apomorphine
    3. History of QTc interval prolongation (QTc \>440) and Torsade de Pointes
    4. Serotonin syndrome
    5. Phenylketonuric patients
    6. Concurrent use of selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs)