What is the maximum amount of meclizine (Antivert) that can be taken in a 24-hour period?

From the Research

The maximum recommended dose of meclizine in a 24-hour period is 50 mg, as supported by the most recent and highest quality study available 1. Typically, meclizine is taken as 12.5 to 25 mg every 4-6 hours as needed for symptoms of motion sickness, vertigo, or dizziness, but should not exceed 50 mg total in a day. For motion sickness prevention, it's best taken 1 hour before travel. For vertigo or dizziness treatment, the medication can be divided into smaller doses throughout the day. Meclizine works by blocking histamine receptors in the brain that trigger nausea and by reducing sensitivity in the inner ear balance system. Some key points to consider when using meclizine include:

• Side effects may include drowsiness, dry mouth, and blurred vision, so avoid driving or operating machinery until you know how it affects you.
• If you're taking other medications, especially other antihistamines or central nervous system depressants, consult your healthcare provider before using meclizine to avoid potential drug interactions.
• The effects of meclizine on motion sickness have been revisited in recent studies, suggesting that it may not primarily work through sensory-specific mechanisms, but rather on a more central level 1.
• Meclizine has been compared to other treatments for motion sickness, such as transdermal scopolamine, and has been found to be effective in some cases, but not as effective as transdermal scopolamine in others 2, 3.
• Meclizine has also been used to treat withdrawal symptoms from transdermal scopolamine therapy, and has been found to be effective in some cases 4.
• A recent study found that meclizine led to a relative increase in torsional velocity compared to placebo during vestibular stimulation, and had an inhibitory effect on eye movement reflexes for low accelerations during visual-vestibular trials 1. It's essential to follow the recommended dosage and consult with a healthcare provider before using meclizine, especially if you have any underlying medical conditions or are taking other medications.