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CYCLIZINE HYDROCHLORIDE

Cyclizine hydrochloride is a medication being studied in clinical trials for its effectiveness in preventing and treating postoperative nausea and vomiting (PONV). This common but distressing side effect affects many patients after surgery, particularly those undergoing bariatric surgery or cesarean sections with spinal anesthesia. Recent clinical trials are comparing cyclizine to other antiemetic medications like metoclopramide and dexamethasone to determine which provides better outcomes for patients. These studies examine how cyclizine affects gastric residual volume and its effectiveness in preventing nausea and vomiting, which could lead to improved recovery and patient satisfaction after surgery.

Table of Contents

What is Cyclizine Hydrochloride?

Cyclizine Hydrochloride is a medication primarily used to prevent and treat nausea and vomiting. It belongs to a class of drugs known as antihistamines, specifically H1-receptor antagonists. Cyclizine is a piperazine derivative that works by blocking certain receptors in the body that trigger nausea and vomiting[1]. This medication is commonly used in various medical settings where patients might experience nausea and vomiting, such as after surgery or during motion sickness.

How Cyclizine Works

Cyclizine works through several mechanisms in the body to prevent nausea and vomiting:

  • It primarily acts as a histamine H1-receptor antagonist, blocking the action of histamine, which can trigger nausea[1]
  • It has some effect on dopamine D2 receptors[1]
  • It affects cholinergic receptors in the body[1]
  • It inhibits the integrative function of the vestibular nuclei (parts of the brain involved in balance and spatial orientation)[1]

Although researchers haven’t fully explained all the ways cyclizine prevents nausea and vomiting, its central anticholinergic properties (blocking certain nerve signals) are partially responsible for its effectiveness. The medication also has central nervous system depressant and local anesthetic effects. Once in the body, cyclizine is metabolized (broken down) to its derivative called norcyclizine, which has little antihistamine activity compared to cyclizine itself[2].

Medical Uses of Cyclizine

Cyclizine is prescribed for several conditions involving nausea and vomiting:

  • Postoperative nausea and vomiting (PONV) – preventing sickness after surgery[2]
  • Motion sickness – preventing or treating nausea related to travel[2]
  • Drug-induced nausea – treating nausea caused by other medications[2]
  • Vertigo – managing dizziness in diseases affecting the vestibular apparatus (the balance system in your inner ear)[2]

Cyclizine can be administered by mouth (orally) or given as an injection (parenterally), depending on the patient’s condition and needs[2].

Cyclizine in Bariatric Surgery

Bariatric surgery (weight loss surgery) patients often experience significant postoperative nausea and vomiting. This can delay recovery by preventing patients from eating normally and moving around after surgery, which may lead to longer hospital stays[1].

Several factors contribute to the high rate of nausea and vomiting after bariatric surgery:

  • Obesity itself
  • Presence of hiatal hernia (when part of the stomach pushes up into the chest)
  • Direct stomach irritation from surgical trauma
  • Presence of blood and secretions in the stomach
  • Abdominal insufflation (inflation of the abdomen with gas during surgery)
  • Surgical duration exceeding 1 hour
  • The use of opioid pain medications[1]

Recent research has been comparing the effectiveness of Cyclizine versus other medications such as Metoclopramide in reducing gastric residual volume (GRV) in bariatric surgery patients. GRV refers to the amount of fluid remaining in the stomach and is considered a predictor of postoperative nausea and vomiting. By measuring GRV using ultrasound, doctors can assess how well these medications are working to improve stomach emptying[1].

Cyclizine for Cesarean Section Patients

Cyclizine is also being studied for use in patients undergoing cesarean section (C-section) who receive intrathecal morphine (morphine injected into the spinal fluid) for pain control. This type of pain control can frequently cause nausea and vomiting as side effects[2].

In this context, cyclizine (50 mg given intravenously) is being compared with dexamethasone (a steroid medication) for preventing nausea and vomiting. The medication is typically administered within 1-2 minutes after the umbilical cord is clamped during the C-section procedure to ensure it doesn’t affect the baby[2].

Comparison with Other Medications

Cyclizine is considered a “second-line” anti-nausea medication in some treatment protocols. This means it may be used when first-line medications aren’t sufficient or appropriate[2].

First-line anti-nausea medications typically include:

  • Serotonin antagonists (like ondansetron)
  • Corticosteroids (like dexamethasone)
  • Dopamine antagonists (like droperidol)[2]

These medications work by different mechanisms and can reduce the risk of nausea and vomiting by about 25% each. They can be used in combination for better effects[2].

In bariatric surgery, cyclizine is being compared with metoclopramide, which is a dopamine receptor antagonist that also has effects on bowel transit time and serotonin receptors at high doses[1].

How Cyclizine is Administered

Cyclizine can be administered in several ways:

  • Oral form – taken by mouth as tablets
  • Intravenous (IV) form – injected directly into a vein

In the clinical trials described, cyclizine was administered intravenously at a dose of 50 mg[1][2]. For bariatric surgery patients, it was delivered in a 10 mL syringe[1], while for cesarean section patients, it was given within 1-2 minutes after the umbilical cord was clamped[2].

Risk Factors for Nausea and Vomiting

Understanding the risk factors for postoperative nausea and vomiting can help you know why cyclizine might be prescribed. These risk factors fall into two main categories[2]:

Patient-related risk factors:

  • Female gender – women are three times more likely than men to experience postoperative nausea and vomiting
  • Age – for adults, the risk decreases with age; for children, those older than 3 years have an increased risk compared to younger children
  • Obesity – patients with a body mass index (BMI) over 30 have double the risk
  • Non-smoking status – non-smokers have roughly double the risk (one theory suggests chemicals in cigarette smoke increase the metabolism of substances that cause nausea)
  • History of gastrointestinal disease – conditions like gastritis or ulcers increase the risk
  • Previous history – prior motion sickness, Meniere’s disease, or previous postoperative nausea and vomiting indicates a general susceptibility[2]

Anesthesia-related risk factors:

  • Volatile anesthetics – use of these gases doubles the risk, with risk increasing with higher doses
  • Opioid use – both during and after surgery increases the risk in a dose-dependent manner by reducing muscle tone and peristaltic activity, delaying stomach emptying
  • Duration of anesthesia – longer exposure to anesthetics and opioids increases risk[2]

Knowing these risk factors can help your healthcare provider determine whether preventive anti-nausea medications like cyclizine might be beneficial for you before or after a surgical procedure[2].

Aspect Details
Drug Name Cyclizine Hydrochloride
Drug Classification Antihistamine (H1-receptor antagonist), also affects dopamine and cholinergic receptors
Typical Dosage 50 mg intravenously
Clinical Trial Applications Bariatric surgery, Cesarean section with spinal anesthesia
Comparison Medications Metoclopramide (10 mg) in bariatric surgery; Dexamethasone (8 mg) in cesarean sections
Primary Outcomes Measured Gastric residual volume, Incidence of postoperative nausea and vomiting
Measurement Timeframes 1 hour post-administration (bariatric); 30 minutes, 3 hours, and 6 hours post-intervention (cesarean)
Mechanism of Action Blocks histamine receptors, affects dopamine receptors, has anticholinergic properties, inhibits vestibular nuclei function
Target Condition Postoperative nausea and vomiting (PONV)

FAQ

  • What is Cyclizine Hydrochloride and how does it work? Cyclizine Hydrochloride is an antiemetic medication (prevents nausea and vomiting) that belongs to the piperazine derivative family. It works primarily as a histamine H1-receptor antagonist. It also has some effects on dopamine (D2) receptors and cholinergic receptors, and it inhibits the function of vestibular nuclei in the brain. These combined actions help reduce signals in the brain that trigger nausea and vomiting, making it useful for preventing postoperative nausea and vomiting in surgical patients.
  • In which types of surgeries is Cyclizine being studied? According to the clinical trial data, Cyclizine is being studied in two main types of surgical procedures: bariatric surgery (weight loss surgery) and cesarean sections. In bariatric surgery, researchers are comparing Cyclizine to metoclopramide to see which better reduces gastric residual volume, which can help prevent nausea and vomiting. In cesarean section procedures, Cyclizine is being compared to dexamethasone for preventing nausea and vomiting specifically after intrathecal morphine (morphine injected into the spinal fluid for pain relief).
  • What is the typical dose of Cyclizine used in these clinical trials? In the clinical trials described, Cyclizine is typically administered at a dose of 50 mg given intravenously (IV). For cesarean section patients, the trial specifies that the Cyclizine is administered within 1-2 minutes after the umbilical cord is clamped. In the bariatric surgery trial, the medication is administered in a 10 mL syringe, though the exact timing isn't specified, but measurements are taken 1 hour after administration.
  • How is Cyclizine compared to other medications in these trials? In the bariatric surgery trial, Cyclizine (50 mg) is being compared to Metoclopramide (10 mg) to determine which medication is more effective at reducing gastric residual volume, which is a predictor of postoperative nausea and vomiting. In the cesarean section trial, Cyclizine (50 mg) is being compared to Dexamethasone (8 mg) to see which is more effective at preventing nausea and vomiting after intrathecal morphine administration. Both trials are using objective measurements to compare the effectiveness of these different antiemetic approaches.
  • What outcomes are being measured in these Cyclizine clinical trials? In the bariatric surgery trial, the primary outcome being measured is estimated gastric volume (in milliliters) based on ultrasound measurements 1 hour after administering the study drugs. They're also tracking the incidence of postoperative nausea and vomiting in the first 24 hours after surgery. In the cesarean section trial, researchers are measuring changes in postoperative nausea and vomiting using a PONV intensity scale at 30 minutes, 3 hours, and 6 hours after intervention. They're also tracking postoperative pain as a secondary outcome using a visual analog scale (VAS).

Ongoing Clinical Trials on CYCLIZINE HYDROCHLORIDE

  • Study of AZD9550 and AZD6234 combination for weight loss in people with obesity or overweight with health complications

    Not recruiting

    1 1
    Investigated diseases:
    Investigated drugs:
    Germany

  • Study on the Safety and Effects of AZD9550 for Overweight and Obese Patients with Non-Alcoholic Steatohepatitis (NASH) with or without Type 2 Diabetes

    Not recruiting

    1 1
    Investigated diseases:
    Investigated drugs:
    Austria Germany Sweden

Glossary

  • Postoperative Nausea and Vomiting (PONV): Nausea, retching, or vomiting that occurs during the first 24-48 hours after surgery. It's a common side effect that can cause patient discomfort and delay recovery.
  • Bariatric Surgery: Weight loss surgery performed on the stomach and/or intestines to help people with obesity lose weight. These procedures typically have a high risk of postoperative nausea and vomiting.
  • Gastric Residual Volume (GRV): The amount of content remaining in the stomach at a given time. In the context of these studies, it's measured by ultrasound and can be a predictor of nausea and vomiting risk.
  • Intrathecal Morphine: A pain medication (morphine) that is injected directly into the spinal fluid during spinal anesthesia. While effective for pain control, it often causes nausea and vomiting as side effects.
  • Antiemetic: A medication that prevents or reduces nausea and vomiting. Cyclizine, metoclopramide, and dexamethasone are all examples of antiemetics studied in these trials.
  • Histamine H1-receptor Antagonist: A type of medication that blocks histamine receptors in the body, which can help prevent allergic responses and, in some cases, reduce nausea and vomiting. Cyclizine works partly through this mechanism.
  • Dopamine Antagonist: Medications that block dopamine receptors in the brain. Metoclopramide works through this mechanism to prevent nausea and vomiting by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ).
  • Corticosteroid: A class of steroid hormones that reduce inflammation and affect immune system function. Dexamethasone is a corticosteroid used in these trials for its antiemetic properties.
  • PONV Intensity Scale: A measurement tool used to assess the severity of postoperative nausea and vomiting, helping researchers quantify patient experiences for comparison between treatment groups.
  • Vestibular Nuclei: Areas in the brain stem involved with balance and spatial orientation. Cyclizine affects these areas, which may contribute to its effectiveness against nausea and vomiting, particularly for motion sickness.
  • Chemoreceptor Trigger Zone (CTZ): An area in the brain that detects toxins in the blood and can trigger vomiting. Many antiemetic medications work by affecting this area.
  • Multimodal Antiemetic Strategy: An approach using multiple different anti-nausea medications together to improve effectiveness, often targeting different pathways involved in nausea and vomiting.

References

  1. https://clinicaltrials.gov/study/NCT06789614
  2. https://clinicaltrials.gov/study/NCT03931135