Cyclizine

1. Introduction

Cyclizine is an antihistamine with antiemetic properties primarily used to manage nausea, vomiting, and vertigo. It works by blocking histamine H1 receptors in the vomiting centre and vestibular system, making it effective for motion sickness and other causes of nausea and vomiting.

2. Indications

  • Approved Indications:
    • Motion sickness.
    • Nausea and vomiting due to various causes (e.g., post-operative, chemotherapy, or radiation therapy).
    • Vertigo associated with inner ear disorders (e.g., Ménière’s disease).
  • Off-Label Uses:
    • Nausea and vomiting in pregnancy (with caution).

3. Dosage

  • Adults and Children ≥12 years:
    • 50 mg orally up to three times daily (maximum: 150 mg/day).
  • Children (6–12 years):
    • 25 mg orally up to three times daily (maximum: 75 mg/day).
  • Elderly:
    • Start with the lowest effective dose due to increased sensitivity to side effects.

4. Administration

  • Tablets can be taken with or without food.
  • For motion sickness, take the first dose at least 30 minutes before travel.

5. Forms Available

  • Tablets: 50 mg.
  • Injectable solution: 50 mg/mL (used for severe nausea/vomiting or in patients unable to take oral medication).

6. Side Effects

6.1. Common Side Effects

  • Drowsiness.
  • Dry mouth.
  • Dizziness.

6.2. Less Common Side Effects

  • Blurred vision.
  • Urinary retention.

6.3. Rare but Serious Side Effects

  • Severe allergic reactions (e.g., rash, swelling, difficulty breathing).
  • Hallucinations or confusion, particularly in elderly patients.

7. Warnings

  • Avoid alcohol and other sedatives as they can exacerbate drowsiness.
  • Use cautiously in patients with glaucoma, prostatic hypertrophy, or bladder outflow obstruction.
  • Not recommended for long-term use due to the risk of dependence and side effects.

8. Precautions

  • Use cautiously in patients with cardiovascular disease due to the risk of tachycardia.
  • May impair the ability to drive or operate machinery; advise patients to avoid such activities if drowsy or dizzy.
  • Use with caution in patients with liver or kidney impairment.

9. Interactions

  • Drug-Drug Interactions:
    • CNS depressants (e.g., alcohol, benzodiazepines, opioids): Increased risk of sedation.
    • Anticholinergic drugs (e.g., atropine): Increased risk of dry mouth, blurred vision, and urinary retention.
    • Monoamine oxidase inhibitors (MAOIs): May increase anticholinergic effects.
  • Drug-Food Interactions:
    • Avoid alcohol, which may enhance CNS depressant effects.

10. Monitoring Parameters

  • Improvement in nausea and vomiting symptoms.
  • Monitor for excessive sedation or confusion, especially in elderly patients.

11. Use in Children

  • Approved for use in children over 6 years at appropriate doses.
  • Not recommended for children under 6 years due to limited safety data.

12. Use in Pregnancy

  • Category B: Limited evidence suggests it may be safe for nausea and vomiting in pregnancy.
  • Use only if benefits outweigh risks; consult a doctor.

13. Use in Elderly

  • Use with caution due to increased sensitivity to sedative and anticholinergic effects, such as confusion and dizziness.

14. Use in Kidney Disease

  • Use cautiously in patients with renal impairment; dose adjustment may not be necessary but monitor closely for side effects.

15. Use in Liver Disease

  • Use cautiously in patients with hepatic impairment, as metabolism may be affected.

16. Patient Counselling Points

  • Take cyclizine as prescribed and avoid exceeding the recommended dose.
  • For motion sickness, take the medication 30 minutes before travel.
  • Avoid alcohol and other sedatives while taking cyclizine.
  • Inform your doctor if side effects such as drowsiness, confusion, or difficulty urinating occur.
  • If used for longer than a few days, discuss with your doctor to reassess the need for continued treatment.

17. Table of Brand Names, Manufacturers, and Prices

Brand NameManufacturerPrice (USD)
ValoidMylan$15–25 (30 tablets, 50 mg)
Generic CyclizineVarious$10–20 (30 tablets, 50 mg)

18. FAQs (15 Questions)

  1. What is cyclizine used for?
    Cyclizine is used to treat nausea, vomiting, and motion sickness.
  2. How does cyclizine work?
    It blocks histamine H1 receptors in the brain to prevent nausea and vomiting.
  3. Can cyclizine cause drowsiness?
    Yes, drowsiness is a common side effect.
  4. Can children take cyclizine?
    Yes, it is approved for children over 6 years at lower doses.
  5. Can cyclizine be used during pregnancy?
    It may be used during pregnancy if prescribed by a doctor for nausea and vomiting.
  6. How long does cyclizine take to work?
    It usually starts working within 30 minutes of taking a dose.
  7. What are the common side effects of cyclizine?
    Common side effects include drowsiness, dry mouth, and dizziness.
  8. How should cyclizine be taken for motion sickness?
    Take the first dose 30 minutes before travel and then as needed.
  9. Does cyclizine interact with other medications?
    Yes, it interacts with CNS depressants, anticholinergic drugs, and MAOIs.
  10. Can I drive while taking cyclizine?
    Avoid driving if you feel drowsy or dizzy.
  11. What should I do if I miss a dose?
    Take it as soon as you remember, but skip it if it’s close to the next dose. Do not double the dose.
  12. Can cyclizine cause confusion?
    Yes, confusion may occur, especially in elderly patients.
  13. Is cyclizine safe for long-term use?
    It is not typically recommended for long-term use due to the risk of side effects.
  14. Can cyclizine be taken with alcohol?
    No, alcohol should be avoided as it increases sedation.
  15. How should cyclizine be stored?
    Store at room temperature, away from light and moisture.