From the Guidelines
Meclizine works as a vestibular suppressant medication by suppressing the central emetic center to relieve nausea and vomiting associated with motion sickness.
Mechanism of Action
- Meclizine is an antihistamine that appears to have a suppressive effect on the central emetic center 1.
- This suppressive effect helps to relieve the nausea and vomiting associated with motion sickness.
- As an antihistamine, meclizine is commonly used to treat symptoms of vertigo and/or associated motion sickness 1.
- The exact mechanism of action of meclizine on the vestibular system is not fully understood, but it is thought to reduce the subjective sensation of spinning and alleviate accompanying motion sickness symptoms 1.
- Meclizine is often used in combination with other medications, such as benzodiazepines, to manage vertigo and motion sickness symptoms 1.
From the FDA Drug Label
12.1 Mechanism of Action The precise mechanism by which meclizine exerts its therapeutic effect is unknown but is presumed to involve antagonism of the histamine H1 receptor.
The mechanism of action of Meclizine is presumed to involve antagonism of the histamine H1 receptor, although the precise mechanism is unknown 2.
From the Research
Mechanism of Action of Meclizine
The mechanism of action of meclizine is complex and involves multiple pathways. Key points include:
- Meclizine is a first-generation H1 antihistamine used in the treatment of motion sickness and vertigo 3, 4, 5.
- The drug may not primarily work through sensory-specific mechanisms, but rather on a more central level, as indicated by its inhibitory effect on eye movement reflexes for low accelerations during visual-vestibular trials 3.
- Molecular docking reveals the binding mechanism of meclizine to the histamine H1 receptor, with conserved binding sites compared to other antihistamines like levocetirizine 4, 5.
- Meclizine's metabolism and pharmacokinetics involve the dominant enzyme CYP2D6, with genetic polymorphism contributing to large interindividual variability 6.
- The drug can act on peripheral elements of the vestibular maculae, as well as central gravity receptor circuits, to exert its suppressive effects 7.
Key Findings
- Meclizine leads to a relative increase in torsional velocity compared to placebo during vestibular stimulation for both low and high intensities 3.
- The visual-vestibular stimuli yield a decrease during low acceleration, but increase during high acceleration 3.
- Meclizine has an inhibitory effect on eye movement reflexes for low accelerations during visual-vestibular trials, indicating a central level of action 3.
- The drug's binding mechanism to the histamine H1 receptor involves conserved binding sites with other antihistamines 4, 5.
- Meclizine's pharmacokinetics involve a rapid onset of action, with a shorter peak time of plasma concentration compared to other formulations 6.