[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [H1 antihistamines](https://durgical.com/en/pharmacology/classes/h1-antihistamines/) › Meclozine

# Meclozine

## H1 antihistamines?

H1 antihistamines

A piperazine antihistamine used to prevent and treat nausea, vomiting and dizziness of motion sickness and vertigo.

Updated Nov 1, 2026

Also called: Meclizine

## Quick facts

**Group**
[H1 antihistamines](https://durgical.com/en/pharmacology/classes/h1-antihistamines/)

**Target**
Histamine H1 receptor

**Used for**
Prevention and treatment

**Key effects**
Drowsiness · Dry mouth · Blurred vision

**Monitor**
Sedation and fall risk · Symptom control

**ATC**
R06AE05

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Histamine H1 receptor**Meclozine

ⓘ The figure shows doxepin, a tricyclic first-generation H1 blocker, in the human H1 receptor; meclozine is thought to act at the same receptor.

**Target in 3D:** Histamine H1 receptor. PDB structure 3RZE (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/3RZE) · Drag to rotate · pinch to zoom

Meclozine is a first-generation H1 antihistamine with central antimuscarinic action. It reduces signals from the inner ear (vestibular system) to the vomiting centre, which is why it works for motion sickness and vertigo. It is most effective when taken before symptoms start. Drowsiness and anticholinergic effects are common.

- Motion stimulates the inner ear and sends signals to the brainstem
- Meclozine blocks H1 and muscarinic receptors on that pathway
- Fewer signals reach the vomiting centre
- Nausea and dizziness are reduced, with some drowsiness

## Indications

- Prevention and treatment of motion sickness
- Vertigo from vestibular disorders [Ménière disease →](https://durgical.com/en/conditions/meniere-disease/)

## Adverse effects

### Common

- Drowsiness
- Dry mouth
- Blurred vision
- Tiredness

### Serious (rare, important)

- Confusion in older adults
- Urinary retention

## Contraindications

- Hypersensitivity to meclozine
- Caution in glaucoma, asthma and prostate enlargement
- Older adults: avoided where possible because of confusion, falls and urinary retention

## Key interactions

**Alcohol, benzodiazepines, opioids and other CNS depressants**
Additive sedation and slowed breathing

**Other anticholinergic drugs (tricyclic antidepressants, oxybutynin, antipsychotics)**
Additive dry mouth, urinary retention, constipation and confusion

## What is monitored

- Sedation and fall risk
- Symptom control

## Administration and safety

- Tablets, chewable tablets or capsules by mouth, taken before the trip starts

## Pregnancy and breastfeeding

Meclozine has been used for nausea in pregnancy; use is decided with the clinician.

## Nursing care

- Explain that it works better before symptoms begin
- Teach not to drive or operate machinery until the effect is known, and to avoid alcohol
- Assess fall risk in older adults with vertigo

## Pharmacokinetics

**Absorption**
Oral

**Metabolism**
Liver

**Onset and duration**
Works best when taken before travel; effect lasts many hours

## Memory aid

MECLozine: Motion, Ear, Car Lurching.

## Test yourself

Think of the answer, then tap the question to see it.

## When is meclozine most effective for motion sickness?

When taken before the motion and symptoms begin.

## Which sensory system's signals does meclozine damp down?

The vestibular system of the inner ear.

## What are two anticholinergic side effects of meclozine?

Dry mouth and blurred vision (also urinary retention).

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/meclozine/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Cyclizine](https://durgical.com/en/pharmacology/cyclizine/)
- [Promethazine](https://durgical.com/en/pharmacology/promethazine/)
- [Diphenhydramine](https://durgical.com/en/pharmacology/diphenhydramine/)

## Related conditions 1

- [Ménière disease](https://durgical.com/en/conditions/meniere-disease/)

[← Back to the class: H1 antihistamines](https://durgical.com/en/pharmacology/classes/h1-antihistamines/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Meclizine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682548.html) (MedlinePlus (U.S. National Library of Medicine), 2018); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=R06AE05) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/meclozine/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/meclozine/