Meclizine

What Does Meclizine Do?

Meclizine is a medication used primarily to prevent and treat nausea, vomiting, and dizziness related to motion sickness. It also helps manage vertigo from vestibular system disorders. Overall, meclizine is a reliable option for managing these conditions, with a well-documented mechanism of action.

Over 40 years ago, I recall my father giving my sister a brown paper bag to sit on during car journeys to help with motion sickness. It seemed to help, but medicine has progressed since then. 

How Does Meclizine Work? (the complicated stuff!)

Meclizine functions by antagonising histamine H1 receptors, which are crucial for transmitting signals related to nausea and vomiting. This inhibition disrupts the signaling pathways from the vestibular nuclei and nucleus tractus solitarius to the chemoreceptor trigger zone and medullary vomiting centre. Additionally, it lowers labyrinth excitability and vestibular stimulation, thereby alleviating symptoms of vertigo and motion sickness. Its central anticholinergic properties further enhance its antiemetic effects by reducing central nervous system activity related to nausea.

Drug Type and Category of Meclizine

Drug Type

Antibacterial Agent

Category

Therapeutic Class: Antibiotic

Pharmacological Class: Nitrofuran derivative

What dosage of Meclizine should you be taking?

The National Health Service (NHS) in the United Kingdom does not provide specific dosage guidelines for meclizine, as it is not commonly prescribed within the UK. However, general dosing recommendations based on international sources ¹ are as follows:

For Motion Sickness:

• Adults and Children Aged 12 and Over:
• Dose: 25 to 50 mg taken orally approximately one hour before travel.
• Frequency: The dose may be repeated every 24 hours if needed.

For Vertigo:

• Adults:
• Dose: 25 to 100 mg per day, taken orally in divided doses, depending on clinical response.

Meclizine is not recommended for children under 12 years of age due to insufficient safety and efficacy data. Additionally, caution is advised when prescribing meclizine to older adults, as they may be more susceptible to side effects such as drowsiness and impaired balance, which can increase the risk of falls. Dose adjustments may be necessary for patients with renal or hepatic impairment.

What are the side-effects of Meclizine?

Common Side Effects (Occur in ?1% of users):

• Drowsiness
• Meclizine has sedative effects, which can impair alertness and coordination.
• Dry Mouth
• Reduced saliva production leading to discomfort.
• Fatigue
• A general sense of tiredness or lethargy.
• Blurred Vision
• Difficulty focusing or seeing clearly.
• Headache

Less Common Side Effects:

• Gastrointestinal:
• Nausea or vomiting (ironically, though it is used to treat nausea, it may also cause it in some cases).
• Constipation.
• Central Nervous System:
• Dizziness.
• Coordination difficulties or feeling unsteady.
• Dermatologic:
• Rash or itching (indicative of a mild allergic reaction).

Rare and Serious Side Effects:

• Allergic Reactions:
• Symptoms such as swelling of the face, lips, tongue, or throat; difficulty breathing; or severe itching/rash (anaphylaxis).
• Confusion and Memory Impairment:
• More common in elderly patients due to the drug’s anticholinergic effects.
• Tachycardia (Increased Heart Rate):
• Though rare, it can occur due to the anticholinergic properties.
• Urinary Retention:
• Difficulty urinating, especially in individuals with an enlarged prostate or pre-existing urinary issues.

Precautions:

• Elderly Patients:
• Increased sensitivity to side effects, particularly drowsiness, confusion, and balance issues, which can lead to falls.
• Driving or Operating Machinery:
• Due to its sedative effects, meclizine can impair the ability to perform tasks requiring full attention.
• Alcohol Use:
• Consuming alcohol while taking meclizine can exacerbate drowsiness and dizziness.

Interactions

1. Drug Interactions

CNS Depressants

• Alcohol, Sedatives, and Tranquilisers:
• Meclizine’s sedative effects may be enhanced, leading to excessive drowsiness, dizziness, or impaired coordination.
• Opioids (e.g., Morphine, Codeine):
• Increased risk of respiratory depression, sedation, and confusion.
• Sleep Medications (e.g., Zolpidem, Diazepam):
• Combined use can significantly increase drowsiness and impair cognitive function.

Anticholinergic Medications

• Antihistamines (e.g., Diphenhydramine), Tricyclic Antidepressants (e.g., Amitriptyline), or Antipsychotics (e.g., Olanzapine):
• Increased anticholinergic effects, such as dry mouth, constipation, urinary retention, and confusion.

Muscle Relaxants

• Enhanced sedative effects and impaired coordination.

Blood Pressure Medications

• Beta Blockers or Antihypertensives:
• May increase the risk of dizziness or fainting due to combined blood pressure-lowering effects.

2. Medical Conditions That May Interact

Glaucoma

• Meclizine’s anticholinergic effects can increase intraocular pressure, worsening symptoms.

Urinary Retention or Benign Prostatic Hyperplasia (BPH)

• Anticholinergic effects may exacerbate difficulty in urination.

Asthma or Chronic Obstructive Pulmonary Disease (COPD)

• Rarely, anticholinergic effects can thicken bronchial secretions, worsening respiratory symptoms.

Liver or Kidney Disease

• Impaired metabolism or excretion of the drug can increase systemic levels, heightening the risk of side effects.

Elderly Patients

• Increased sensitivity to sedation, confusion, and balance issues, leading to a higher risk of falls and cognitive impairment.

3. Food and Lifestyle Interactions

Alcohol

• Amplifies sedation and impairs cognitive and motor functions.

Food

• Taking meclizine with food may reduce gastrointestinal discomfort, although it is not strictly necessary.

4. Laboratory Test Interactions

• No significant effects on laboratory tests are known.

Recommendations for Safe Use

• Inform your healthcare provider about all medications, supplements, and medical conditions before starting meclizine.
• Avoid alcohol or other CNS depressants while using meclizine.
• Use caution when engaging in activities that require alertness, such as driving or operating machinery.

Natural Alternatives to Meclizine

1. Ginger

Ginger is one of the most well-researched natural remedies for nausea and motion sickness. Active compounds such as gingerol and shogaol are thought to influence the gastrointestinal system and central nervous system to reduce nausea². Studies have shown that ginger may be as effective as over-the-counter medications like dimenhydrinate for motion sickness and postoperative nausea³.

2. Peppermint

Peppermint oil, particularly in capsule form, has antispasmodic properties that can relieve gastrointestinal discomfort associated with nausea⁴. The menthol in peppermint also has a calming effect on the stomach, reducing symptoms of queasiness⁵.

3. Acupressure

Applying pressure to the P6 acupoint, located on the inner wrist, has been shown to alleviate nausea and vomiting in conditions such as motion sickness, pregnancy, and postoperative recovery⁶. Wristbands designed for this purpose, such as Sea-Bands, are commonly used and drug-free. This may be more of a placebo effect, but if it works, then great. 

4. Vitamin B6 (Pyridoxine)

Vitamin B6 has been shown to reduce nausea in pregnancy (morning sickness) and is often recommended as a first-line treatment⁷. It may also be beneficial for other forms of mild nausea, though it is not a treatment for vertigo.

5. Chamomile

Chamomile has mild sedative and anti-inflammatory properties that may help alleviate nausea and vertigo, especially if anxiety contributes to the symptoms⁸. Drinking chamomile tea can also promote relaxation and ease stomach upset.

6. Lemon Balm

Lemon balm, a member of the mint family, has calming and anti-nausea effects. It may help with mild vertigo and associated symptoms by reducing anxiety and stabilising the central nervous system⁹.

7. Aromatherapy

Inhalation of essential oils such as lavender, peppermint, or lemon may alleviate nausea and dizziness. Aromatherapy is particularly useful for those sensitive to oral treatments or supplements¹⁰. 

8. Hydration and Electrolytes

Dehydration can exacerbate symptoms of nausea and dizziness. Drinking water or electrolyte-rich fluids can help stabilise the body's systems and alleviate mild vertigo symptoms¹¹.

9. Vestibular Rehabilitation Therapy (VRT)

While not a direct alternative to meclizine, VRT involves exercises designed to improve balance and reduce dizziness over time. This is particularly useful for managing chronic vertigo or vestibular disorders¹².

10. Ginkgo Biloba

Ginkgo biloba is an herbal remedy known to improve circulation, including to the brain. It has been used for reducing dizziness and vertigo symptoms, particularly in conditions like vestibular disorders¹³.

Interesting facts about Meclizine

NASA astronauts have used meclizine to combat space motion sickness, demonstrating its effectiveness in extreme conditions where vestibular disruption is common.

Unlike some medications used to treat vertigo and nausea (e.g., benzodiazepines), meclizine does not have a significant risk of dependence or addiction, making it a safer option for long-term use.

Disclaimer

This article is generated for informational purposes only. It was created in March 2025. Medications and medical guidance can change over time. Therefore, it is essential to consult with your general practitioner or healthcare provider before making any decisions regarding medications or treatment plans. Your GP can provide personalised advice based on your specific health needs and conditions.

References

1. https://www.drugs.com/meclizine.html
2. Ernst E, Pittler MH. Efficacy of ginger for nausea and vomiting: a systematic review of randomized clinical trials. British Journal of Anaesthesia. 2000;84(3):367-371.
3. Grontved A, Hentzer E. Vertigo-reducing effect of ginger root. Acta Otolaryngol. 1986;101(5-6):278-281.
4. Micklefield GH, et al. Peppermint oil in the treatment of irritable bowel syndrome: a prospective double-blind placebo-controlled randomized trial. Digestive Diseases and Sciences. 1998;43(11):2593-2600.
5. Hills JM, Aaronson PI. The mechanism of action of peppermint oil on gastrointestinal smooth muscle. Gastroenterology. 1991;101(1):55-65.
6. Roscoe JA, Morrow GR, et al. Acupressure and nausea control: a review of the scientific evidence. CA Cancer J Clin. 2009;59(1):61-63.
7. Sahakian V, Rouse D, et al. Vitamin B6 is effective therapy for nausea and vomiting of pregnancy: a randomized, double-blind placebo-controlled study. Obstetrics & Gynecology. 1991;78(1):33-36.
8. Srivastava JK, Shankar E, et al. Chamomile: A herbal medicine of the past with bright future. Molecular Medicine Reports. 2010;3(6):895-901.
9. Kennedy DO, Scholey AB. The psychopharmacology of European herbs with cognition-enhancing properties. Current Pharmaceutical Design. 2006;12(35):4613-4623.
10. Lua PL, Zakaria NS. A brief review of current scientific evidence involving aromatherapy use for nausea and vomiting. Journal of Alternative and Complementary Medicine. 2012;18(6):534-540.
11. Ritz T, Kullowatz A. Effects of hydration on health. Current Opinion in Clinical Nutrition & Metabolic Care. 2008;11(6):733-740.
12. Herdman SJ. Vestibular rehabilitation. Current Opinion in Neurology. 2013;26(1):61-68.
13. Holgers KM, Holmkvist MW. Ginkgo biloba extract in the treatment of vertigo and tinnitus: a review. Ear, Nose, & Throat Journal. 2000;79(8):605-607.