What is the dosage and usage of Meclizine (Antihistamine) for treating vertigo and motion sickness?

From the Guidelines

Meclizine is used to treat vertigo and motion sickness at a dosage of 25-50 mg, 1 hour before travel or activity, with a maximum daily dose not exceeding 150 mg, as it helps reduce sensitivity to motion and decreases stimulation of the vestibular system by blocking histamine H1 receptors in the brain 1. When considering the treatment of vertigo and motion sickness, it is essential to weigh the benefits and risks of medication use. Meclizine, an antihistamine, is commonly used for this purpose.

• The recommended dosage is 25-50 mg, taken 1 hour before travel or activity for motion sickness, or every 4-6 hours as needed for vertigo symptoms.
• The maximum daily dose should not exceed 150 mg.
• Meclizine works by blocking histamine H1 receptors in the brain, which helps reduce sensitivity to motion and decreases stimulation of the vestibular system (inner ear) 1. However, it is crucial to note that vestibular suppressant medications, including meclizine, are not recommended for routine treatment of benign paroxysmal positional vertigo (BPPV) due to a lack of evidence supporting their effectiveness as a primary treatment 1.
• Common side effects of meclizine include drowsiness, dry mouth, and blurred vision, so patients should avoid driving or operating machinery until they know how the medication affects them.
• Meclizine should be used with caution in elderly patients and those with glaucoma, prostatic hypertrophy, or urinary retention.
• The medication is available over-the-counter in 12.5-25 mg tablets or by prescription in 25-50 mg strengths, and can be taken with or without food.

From the FDA Drug Label

Meclizine hydrochloride tablets are indicated for the treatment of vertigo associated with diseases affecting the vestibular system in adults. The recommended dosage is 25 mg to 100 mg daily administered orally, in divided doses, depending upon clinical response.

• Meclizine Usage: Meclizine is used for the treatment of vertigo associated with diseases affecting the vestibular system in adults.
• Dosage: The recommended dosage of meclizine is 25 mg to 100 mg daily, administered orally in divided doses, depending upon clinical response 2.
• Administration: Meclizine hydrochloride tablets must be swallowed whole 2.

From the Research

Meclizine Usage and Dosage

• Meclizine is an antihistamine used for the prophylactic treatment and management of motion sickness and vertigo 3.
• The onset of action of meclizine is about 1 hour for the treatment of motion sickness and vertigo 3.
• A new suspension formulation of meclizine was developed to achieve a rapid effect, with the plasma concentration appearing more rapidly in comparison to the marketed meclizine oral tablet 3.

Effects of Meclizine on Motion Sickness

• Meclizine led to a relative increase in torsional velocity compared to placebo during vestibular stimulation for both intensities 4.
• Meclizine had an inhibitory effect on eye movement reflexes for low accelerations during visual-vestibular trials, indicating that it may not primarily work through sensory-specific mechanisms, but rather on a more central level 4.
• Meclizine shows promise in targeting motion-sickness evoked by everyday activities, but its use may be counterproductive in high-acceleration environments 4.

Physiological and Behavioral Effects of Meclizine

• Meclizine affects the auditory system, with changes in distortion-product otoacoustic emissions, the Repeated Evoked Potentials version of the Auditory Brainstem Response, and quantitative electroencephalography measured over the left and right sides of the auditory cortex 5.
• Meclizine also affects hand-eye coordination, with implications for its use in vestibular rehabilitation and improving performance in learning-disordered children 5.

Therapeutic Effects of Meclizine on Vestibular Function

• Meclizine acts on peripheral elements of the vestibular maculae to suppress vestibular function and reduce abnormal sensitivity to head motions 6.
• Meclizine also acts centrally to exert its suppressive effects, with findings indicating that it can act on central gravity receptor circuits 6.

Side Effects of Meclizine

• Meclizine can cause side effects such as sleepiness, tiredness, blurred vision, concentration problems, and dizziness 7.
• Meclizine can also affect short-term memory, with decreased accuracy on the Sternberg working memory task 7.
• Meclizine has an acceptable combination of side effects compared to other anti-motion sickness drugs, making it a suitable option for treatment 7.