Meclizine

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# Overview
Meclizine is a antiemetic, antihistamine, antivertigo and central nervous system agent that is FDA approved for the treatment of nausea, vomiting and dizziness associated with motion sickness and vertigo.   Common adverse reactions include drowsiness, xerostomia, sedation and somnolence.

# Adult Indications and Dosage

## FDA-Labeled Indications and Dosage (Adult)
- Based on a review of this drug by the National Academy of Sciences - National Research Council and/or other information, FDA has classified the indications as follows:
- Effective:
- Management of nausea and vomiting, and dizziness associated with motion sickness.
- Possibly Effective:
- Management of vertigo associated with diseases affecting the vestibular system.
- Final classification of the less than effective indications requires further investigation.

### Dosing Information
- For the control of vertigo associated with diseases affecting the vestibular system, the recommended dose is 25 to 100 mg daily, in divided dosage, depending upon clinical response.
- The initial dose of 25 to 50 mg of Meclizine should be taken one hour prior to embarkation for protection against motion sickness. Thereafter, the dose may be repeated every 24 hours for the duration of the journey.

## Off-Label Use and Dosage (Adult)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Meclizine in adult patients.

### NonGuideline-Supported Use
- Radiation-induced nausea and vomiting; Treatment and Prophylaxis
- Dosage
50 mg Oral, 2 to 12 hrs prior to radiotherapy
- 50 mg Oral, 2 to 12 hrs prior to radiotherapy
- Vomiting of pregnancy
- Dosage
25 to 50 mg oral daily
- 25 to 50 mg oral daily

# Pediatric Indications and Dosage

## FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Meclizine in pediatric patients.

## Off-Label Use and Dosage (Pediatric)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Meclizine in pediatric patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Meclizine in pediatric patients.

# Contraindications
- Meclizine HCl is contraindicated in individuals who have shown a previous hypersensitivity to it.

# Warnings
- Since drowsiness may, on occasion, occur with use of this drug, patients should be warned of this possibility and cautioned against driving a car or operating dangerous machinery.
- Patients should avoid alcoholic beverages while taking this drug.
- Due to its potential anticholinergic action, this drug should be used with caution in patients with asthma, glaucoma, or enlargement of the prostate gland.
- Clinical studies establishing safety and effectiveness in children have not been done; therefore, usage is not recommended in children under 12 years of age.

# Adverse Reactions

## Clinical Trials Experience
- Anaphylactoid reaction, drowsiness, dry mouth, headache, fatigue, vomiting and, on rare occasions, blurred vision have been reported.

## Postmarketing Experience
There is limited information regarding Postmarketing Experience of Meclizine in the drug label.

# Drug Interactions
- There may be increased CNS depression when meclizine is administered concurrently with other CNS depressants, including alcohol, tranquilizers, and sedatives.
- Based on in-vitro evaluation, meclizine is metabolized by CYP2D6. Therefore there is a possibility for a drug interaction between meclizine and CYP2D6 inhibitors.

# Use in Specific Populations

### Pregnancy
Pregnancy Category (FDA): B
- Reproduction studies in rats have shown cleft palates at 2550 times the human dose. Epidemiological studies in pregnant women, however, do not indicate that meclizine increases the risk of abnormalities when administered during pregnancy. Despite the animal findings, it would appear that the possibility of fetal harm is remote. Nevertheless, meclizine, or any other medication, should be used during pregnancy only if clearly necessary.
Pregnancy Category (AUS):
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Meclizine in women who are pregnant.

### Labor and Delivery
There is no FDA guidance on use of Meclizine during labor and delivery.

### Nursing Mothers
- It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when meclizine is administered to a nursing woman.

### Pediatric Use
There is no FDA guidance on the use of Meclizine with respect to pediatric patients.

### Geriatic Use
There is no FDA guidance on the use of Meclizine with respect to geriatric patients.

### Gender
There is no FDA guidance on the use of Meclizine with respect to specific gender populations.

### Race
There is no FDA guidance on the use of Meclizine with respect to specific racial populations.

### Renal Impairment
- The effect of renal impairment on the pharmacokinetics of meclizine has not been evaluated. Due to a potential for drug/metabolite accumulation, meclizine should be administered with caution in patients with renal impairment and in the elderly as renal function generally declines with age.

### Hepatic Impairment
- The effect of hepatic impairment on the pharmacokinetics of meclizine has not been evaluated. As meclizine undergoes metabolism, hepatic impairment may result in increased systemic exposure of the drug. Treatment with meclizine should be administered with caution in patients with hepatic impairment.

### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Meclizine in women of reproductive potentials and males.

### Immunocompromised Patients
There is no FDA guidance one the use of Meclizine in patients who are immunocompromised.

# Administration and Monitoring

### Administration
- Oral

### Monitoring
There is limited information regarding Monitoring of Meclizine in the drug label.
- Description

# IV Compatibility
There is limited information regarding IV Compatibility of Meclizine in the drug label.

# Overdosage
There is limited information regarding Chronic Overdose of Meclizine in the drug label.

# Pharmacology

## Mechanism of Action
- Meclizine 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.

## Structure
- Chemically, Meclizine HCl is 1-(p-chloro--phenylbenzyl)-4-(m-methylbenzyl) piperazine dihydrochloride monohydrate.

## Pharmacodynamics
There is limited information regarding Pharmacodynamics of Meclizine in the drug label.

## Pharmacokinetics
- The available pharmacokinetic information for meclizine following oral administration has been summarized from published literature.
- 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.
- Drug distribution characteristics for meclizine in humans are unknown.
- 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.
- Meclizine has a plasma elimination half-life of about 5-6 hours in humans.

## Nonclinical Toxicology
There is limited information regarding Nonclinical Toxicology of Meclizine in the drug label.

# Clinical Studies
There is limited information regarding Clinical Studies of Meclizine in the drug label.

# How Supplied
Antivert: 12.5 mg tablets:
Bottles of 100
(NDC 0049-2100-66)
Antivert/25: 25 mg tablets:
Bottles of 100
(NDC 0049-2110-66)
Meclizine/50: 50 mg tablets:
Bottles of 100
(NDC 0049-2140-66)

## Storage
There is limited information regarding Meclizine Storage in the drug label.

# Images

## Drug Images

## Package and Label Display Panel
NDC 0049-2100-66
100 Tablets
Meclizine 
(meclizine HCl)
12.5 mg
Pfizer 
Distributed by 
Roerig 
Division of Pfizer Inc, NY, NY 10017
NDC 0049-2110-66
100 Tablets
Antivert 
(meclizine HCl)
25 mg
Pfizer 
Distributed by 
Roerig 
Division of Pfizer Inc, NY, NY 10017
NDC 0049-2140-66
100 Tablets
Antivert 
(meclizine HCl)
50 mg
Pfizer 
Distributed by 
Roerig 
Division of Pfizer Inc, NY, NY 10017

# Patient Counseling Information
There is limited information regarding Patient Counseling Information of Meclizine in the drug label.

# Precautions with Alcohol
- Alcohol-Meclizine interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

# Brand Names
- Antivert
- Antivert/25
- Antivert/50
- Dramamine II
- Meclicot
- Meni-D
- Motion Sickness Relief
- Simply Motion

# Look-Alike Drug Names
- Antivert - Axert

# Drug Shortage Status

# Price