Meclizine hydrochloride tablets are indicated for the treatment of vertigo associated with diseases affecting the vestibular system in adults.
2.1 Recommended Dosage
The recommended dosage is 25 mg to 100 mg daily administered orally, in divided doses, depending upon clinical response.
2.2 Administration Instructions
Tablets
Meclizine hydrochloride tablets must be swallowed whole.
12.5 mg: light blue colored, oval shaped tablets with “AN 441” debossed on one side and plain on the other side.
25 mg: light yellow colored, oval shaped tablets with “AN 442” debossed on one side and plain on the other side.
50 mg: white, oval shaped, partially bisected tablets with “AN 444” debossed on one side and plain on the other side.
Meclizine hydrochloride tablets are contraindicated in patients with a hypersensitivity to meclizine or any of the inactive ingredients [see Adverse Reactions (6) and Description (11)].
5.1 Drowsiness
Since drowsiness may occur with use of meclizine hydrochloride, patients should be warned of this possibility and cautioned against driving a car or operating dangerous machinery.
Patients should avoid alcoholic beverages while taking meclizine hydrochloride [see Drug Interactions (7.1)].
5.2 Concurrent Medical Conditions
Because of its potential anticholinergic action, meclizine hydrochloride should be used with caution in patients with asthma, glaucoma, or enlargement of the prostate gland.
The following adverse reactions associated with the use of meclizine hydrochloride were identified in clinical studies or postmarketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Anaphylactic reaction, drowsiness, dry mouth, headache, fatigue, and vomiting. On rare occasions blurred vision has been reported.
7.1 CNS Depressants
There may be increased CNS depression when meclizine hydrochloride is administered concurrently with other CNS depressants, including alcohol [see Warnings and Precautions (5.1)].
7.2 CYP2D6 Inhibitors
Based on in-vitro evaluation, meclizine is metabolized by CYP2D6. Therefore, there is a possibility for a drug interaction between meclizine hydrochloride and CYP2D6 inhibitors. Therefore, monitor for adverse reactions and clinical effect accordingly.
7.1 CNS Depressants
There may be increased CNS depression when meclizine hydrochloride is administered concurrently with other CNS depressants, including alcohol [see Warnings and Precautions (5.1)].
7.2 CYP2D6 Inhibitors
Based on in-vitro evaluation, meclizine is metabolized by CYP2D6. Therefore, there is a possibility for a drug interaction between meclizine hydrochloride and CYP2D6 inhibitors. Therefore, monitor for adverse reactions and clinical effect accordingly.
Meclizine hydrochloride, a histamine (H1) receptor antagonist, is a white or slightly yellowish, crystalline powder. It has the following structural formula:
[1]
Chemically, meclizine hydrochloride is 1-(p-chloro-α-phenylbenzyl)-4-(m-methylbenzyl) piperazine dihydrochloride monohydrate.
Inactive ingredients for the tablets are: colloidal silicon dioxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium starch glycolate and talc. The 12.5 mg tablets also contain FD&C Blue #1 Aluminum Lake. The 25 mg tablets also contain D&C Yellow #10 Aluminum Lake.
Each meclizine hydrochloride 12.5 mg tablet contains 12.5 mg of meclizine dihydrochloride equivalent to 10.53 mg of meclizine free base.
Each meclizine hydrochloride 25 mg tablet contains 25 mg of meclizine dihydrochloride equivalent to 21.07 mg of meclizine free base.
Each meclizine hydrochloride 50 mg tablet contains 50 mg of meclizine dihydrochloride equivalent to 42.14 mg of meclizine free base.
12.1 Mechanism of Action
The precise mechanism by which meclizine exerts its therapeutic effect is unknown but is presumed to involve antagonism of the histamine H1 receptor.
12.2 Pharmacodynamics
There are no relevant pharmacodynamic data regarding meclizine.
12.3 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.
Elimination
Meclizine has a plasma elimination half-life of about 5 to 6 hours in humans.
Metabolism 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.
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenesis
Animal studies to assess the carcinogenic potential of meclizine have not been conducted.
Mutagenesis
Genetic toxicology studies of meclizine have not been conducted.
Impairment of Fertility
Animal studies to assess the effects of meclizine on fertility and early embryonic development have not been conducted.
16.1 How Supplied
Meclizine Hydrochloride Tablets USP, 12.5 mg are supplied as light blue colored, oval shaped tablets with “AN 441” debossed on one side and plain on the other side.
They are available as follows:
Bottles of 30:
Bottles of 100:
Bottles of 500:
Bottles of 1000:
Blister packs:
(Packages of 100 unit doses, 10 cards of 10 tablets each)
Meclizine Hydrochloride Tablets USP, 25 mg are supplied as light yellow colored, oval shaped tablets with “AN 442” debossed on one side and plain on the other side.
They are available as follows:
Bottles of 30:
Bottles of 100:
Bottles of 500:
Bottles of 1000:
Blister packs:
(Packages of 100 unit doses, 10 cards of 10 tablets each)
Meclizine Hydrochloride Tablets USP, 50 mg are supplied as white, oval shaped, partially bisected tablets with “AN 444” debossed on one side and plain on the other side.
They are available as follows:
Bottles of 30:
Bottles of 100:
Bottles of 500:
Bottles of 1000:
Blister packs:
(Packages of 100 unit doses, 10 cards of 10 tablets each)
16.2 Storage and Handling
Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].
Dispense in a tight, light-resistant container as defined in the USP.
Keep this and all medication out of the reach of children.
Administration Instructions
Advise patients that the tablets must be swallowed whole [see Dosage and Administration (2.1)].
Adverse Reactions
Advise patients that meclizine hydrochloride may cause anaphylactic reaction, drowsiness, dry mouth, headache, fatigue, vomiting and, on rare occasions, blurred vision [see Warnings and Precautions (5.1), Adverse Reactions (6)].
Inform patients that meclizine hydrochloride may impair their ability to engage in potentially dangerous activities, such as operating machinery or vehicles.
Concomitant Drug Interactions
Advise patients regarding medications that should not be taken in combination with meclizine hydrochloride or that may necessitate increased monitoring [see Drug Interactions (7.1, 7.2)]. Inform patients that alcohol may increase adverse reactions.
Concurrent Medical Conditions
Advise patients to notify their healthcare provider about all of their medical conditions, including if they are pregnant or plan to become pregnant or if they are breastfeeding [see Warnings and Precautions (5.2), Use in Specific Populations (8.1, 8.2)].
Distributed by:
Amneal Pharmaceuticals LLC
Bridgewater, NJ 08807
Rev. 07-2019-04
