Meclizine

No information provided.

Serious side effects have been reported with meclizine. See the "Drug Precaution" section.

Common side effects of meclizine include the following:

• drowsiness
• dry mouth
• headache
• fatigue
• vomiting
• blurred vision (rare)

This is not a complete list of meclizine side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1800-FDA-1088

Tell our doctor about all the medicines you take, including prescription an non-prescription medicines, vitamins , and herbal supplements. Especially tell your doctor if you take:

• Medications that block a protein in the body (CYP2D6) such as quinidine (Qualaquin), fluoxetine (Prozac,Sarafem), amitriptyline (Elavil, Amitril, Amitid), and paroxetine (Paxil)
• Alcohol
• Tranquilaizers
• Sedatives such as benzodiazepines

This is not a complete list of meclizine drug interactions. Ask you doctor or pharmacist for more information.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Meclizine falls into category B. In animal studies, pregnant animals were given meclizine and some babies had problems. But in human studies, pregnant women were given this medication and their babies did not have any problems related to this medication.

Take meclizine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

Dosing

The dose of meclizine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of meclizine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (tablets):
  • For nausea, vomiting, and dizziness caused by motion sickness:
    • Adults—At first, 25 to 50 milligrams (mg) taken 1 hour before travel. You may take another dose once every 24 hours while traveling.
    • Children 12 years of age and older—Use and dose must be determined by your doctor.
    • Children younger than 12 years of age—Use is not recommended.
  • For vertigo:
    • Adults—25 to 100 milligrams (mg) per day, taken in divided doses.
    • Children 12 years of age and older—Use and dose must be determined by your doctor.
    • Children younger than 12 years of age—Use is not recommended.

Missed Dose

If you miss a dose of meclizine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Meclizine HCl is an antihistamine that shows marked protective activity against nebulized histamine and lethal doses of intravenously injected histamine in guinea pigs. It has a marked effect in blocking the vasodepressor response to histamine, but only a slight blocking action against acetylcholine. Its activity is relatively weak in inhibiting the spasmogenic action of histamine on isolated guinea pig ileum.

Pharmacokinetics

The available pharmacokinetic information for Meclizine following oral administration has been summarized from published literature.

Absorption

Meclizine is absorbed after oral administration with maximum plasma concentrations reaching at a median Tmax value of 3 hours post-dose (range: 1.5 to 6 hours) for the tablet dosage form.

Distribution

Drug distribution characteristics for Meclizine in humans are unknown.

Metabolism

The metabolic fate of Meclizine in humans is unknown. In an in vitro metabolic study using human hepatic microsome and recombinant CYP enzyme, CYP2D6 was found to be the dominant enzyme for metabolism of Meclizine.

The genetic polymorphism of CYP2D6 that results in extensive-, poor-, intermediate- and ultrarapid metabolizer phenotypes could contribute to large inter-individual variability in Meclizine exposure.

Elimination

Meclizine has a plasma elimination half-life of about 5 to 6 hours in humans.

Management of nausea and vomiting, and dizziness associated with motion sickness.

Motion Sickness

The initial dose of 25 mg to 50 mg of Meclizine HCl tablets, USP should be taken one hour prior to travel for protection against motion sickness. Thereafter, the dose may be repeated every 24 hours for the duration of the journey.

Meclizine Hydrochloride Tablets, USP

12.5 mg

100 Tablets

(MEK li zeen)

• Antivert
• Meclizine HCl
• Meclizine Hydrochloride
• Meclozine Hydrochloride

~1 hour (Wang 2012)

Time to Peak

Plasma: 3.1 ± 1.4 hours (Wang 2011, Wang 2012)

Children ≥12 years and Adolescents: Refer to adult dosing.

There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied); use with caution.

There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied); use with caution.