Meclizine

How it works

     * Meclizine is used for a number of different conditions, such as
       nausea associated with motion sickness or radiation therapy.
     * Meclizine blocks H1-histamine receptors, reducing the effects of
       histamine such as vasodilation (opening up of the blood vessels)
       and increased permeability, narrowing of the airways, and stomach
       cramps. Meclizine also has an anticholinergic action (this means it
       blocks the effect of acetylcholine, a neurotransmitter, on
       muscarinic receptors). Both these effects reduce stimulation of the
       vomiting center (one of the areas of the brain thought to control
       vomiting) from the vestibular system (the structure within each ear
       that provides the brain with sensory information about motion,
       equilibrium, and spatial orientation). These actions are thought to
       contribute to the antiemetic effect of meclizine. Meclizine may
       also act directly on the chemoreceptor trigger zone.
     * Meclizine belongs to the class of drugs known as first-generation
       antihistamines. It may also be called an antiemetic.

Upsides

     * Used to treat nausea, vomiting, and dizziness associated with
       motion sickness.
     * May also be used off-label (this means it is not an FDA approved
       use but it is still commonly used for this reason) to relieve
       symptoms of vertigo associated with diseases such as labyrinthitis
       and Meniere's disease. May occasionally be given for the treatment
       of nausea during pregnancy or as a result of radiation therapy.
     * Not as sedating as some other medicines used for motion sickness.
     * Generic meclizine is available.

Downsides

   If you are between the ages of 18 and 60, take no other medication or
   have no other medical conditions, side effects you are more likely to
   experience include:
     * May cause drowsiness or dizziness and affect a person's ability to
       drive or operate machinery. Avoid alcohol because it may enhance
       these side effects.
     * May also cause a dry mouth, a headache, tiredness, and rarely,
       blurred vision.
     * Not recommended for use in children under 12 years of age.
     * May not be suitable for people with asthma, glaucoma, liver or
       kidney disease, or prostate gland enlargement. The elderly or frail
       may be particularly sensitive to meclizine's effects.
     * May interact with a number of other drugs including those that also
       cause sedation or drugs that are also metabolized by CYP2D6 hepatic
       enzymes.
     * Rarely, allergic-type reactions to meclizine have been reported.

   Notes: In general, seniors or children, people with certain medical
   conditions (such as liver or kidney problems, heart disease, diabetes,
   seizures) or people who take other medications are more at risk of
   developing a wider range of side effects. For a complete list of all
   side effects, [84]click here.

Bottom Line

   Meclizine relieves nausea and vomiting associated with motion sickness;
   however, it takes approximately an hour to start working and may cause
   drowsiness.

Tips

     * Take one hour prior to travel when used to prevent motion sickness
       from developing. The dosage of meclizine may be repeated every 24
       hours for the duration of the journey.
     * Do not drive or operate machinery if meclizine makes you drowsy or
       impairs your judgment. Avoid drinking alcohol while taking
       meclizine as this may add to its side effects.
     * Do not give meclizine to children under the age of 12.

Response and Effectiveness

     * Meclizine works in about an hour when used for motion sickness. It
       should be taken at least an hour before travel for maximal benefit.
       The effects of meclizine persist for 8 to 24 hours

References