Meclizine

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Meclozine
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"Bonine" and "Dramamine II" redirect here. For the surname, see Bonine (surname). For other uses, see Dramamine (disambiguation).

Meclizine
Clinical data
Trade namesBonine, Antivert, others
Other namesMeclozine
AHFS/Drugs.comMonograph
MedlinePlusa682548
License data
under the tongue, in the cheek
ATC code
Legal status
Legal status
  • AU: S4 (Prescription only)
  • CA: OTC
  • US: OTC
Pharmacokinetic data
MetabolismLiver
Elimination half-life6 hours
Identifiers
  • (RS)-1-[(4-chlorophenyl)(phenyl)methyl]-4-(3-methylbenzyl)piperazine
JSmol)
Boiling point230 °C (446 °F)
  • Clc1ccc(cc1)C(c2ccccc2)N3CCN(CC3)Cc4cccc(c4)C
  • InChI=1S/C25H27ClN2/c1-20-6-5-7-21(18-20)19-27-14-16-28(17-15-27)25(22-8-3-2-4-9-22)23-10-12-24(26)13-11-23/h2-13,18,25H,14-17,19H2,1H3 checkY
  • Key:OCJYIGYOJCODJL-UHFFFAOYSA-N checkY
 ☒NcheckY (what is this?)  (verify)

Meclizine, sold under the brand name Bonine, among others, is an antihistamine used to treat motion sickness and dizziness (vertigo).[1] It is taken by mouth.[1] Effects generally begin in an hour and last for up to a day.[1]

Common side effects include sleepiness and dry mouth.

allergic reactions.[1] Use in pregnancy appears safe, but has not been well studied; use in breastfeeding is of unclear safety.[2] It is believed to work in part by anticholinergic and antihistamine mechanisms.[1]

Meclizine was patented in 1951 and came into medical use in 1953.

over the counter.[1][4] In 2021, it was the 136th most commonly prescribed medication in the United States, with more than 4 million prescriptions.[5][6]

Medical uses

Meclizine is used to treat symptoms of

elderly due to increased risk of confusion and amnesia.[7]

Motion sickness

Meclizine is effective in inhibiting nausea, vomiting, and dizziness caused by motion sickness.[8]

The drug is safe for treating nausea in pregnancy and is a first-line therapy for this use.[9][10] Doxylamine is similarly safe. Meclizine may not be strong enough for especially sickening motion stimuli, and second-line defenses should be tried in those cases.[11]

Vertigo

Meclizine may be used to treat vertigo, such as in those with Ménière's disease.[12][13]

Side effects

Some common side effects such as drowsiness, dry mouth, and tiredness may occur. Meclizine has been shown to have fewer dry mouth side effects than the traditional treatment for motion sickness, transdermal

scopolamine.[14] A very serious allergic reaction to this drug is unlikely, but immediate medical attention should be sought if it occurs. Symptoms of a serious allergic reaction may include rash, itching, swelling, severe dizziness, and trouble breathing.[15]

Drowsiness

Drowsiness may result as a side effect of taking meclizine. Users are advised not to operate heavy machinery while under the influence. The consumption of alcohol while under the influence of meclizine may result in additional drowsiness.[1]

Elderly

As with any

geriatric population (older than 65 years). Therefore, caution should be used when administering meclizine to the elderly.[16]

Mechanism of action

Meclizine is an antagonist at H1 receptors. It possesses

central nervous system depressant, and local anesthetic effects. Its antiemetic and antivertigo effects are not fully understood, but its central anticholinergic properties are partially responsible. The drug depresses labyrinth excitability and vestibular stimulation, and it may affect the medullary chemoreceptor trigger zone.[7] It has, however, been suggested that meclizine only has an inhibitory effect under normal viewing-circumstances, as the drug has been shown to enhance an isolated vestibular response. Much as motion sickness arises from a discrepancy between multiple senses, meclizine most likely affects a wide array of sensory mechanisms related to self-motion.[17]
Meclizine also is a dopamine antagonist at D1-like and D2-like receptors[citation needed] but does not cause catalepsy[note 1] in mice, perhaps because of its anticholinergic activity.[18]

Chemistry

Meclizine is a

first-generation antihistamine (nonselective H1 antagonist) of the piperazine class. It is structurally and pharmacologically similar to buclizine, cyclizine, and hydroxyzine, but has a shorter half-life of six hours compared to cyclizine and hydroxyzine with about 20 hours (though half-life should not be confused with duration).[citation needed] It is used as an antivertigo/antiemetic agent, specifically in the prevention and treatment of nausea, vomiting, and dizziness associated with motion sickness.[7] Meclizine is sometimes combined with opioids, especially ones of the open-chain class like methadone, dextropropoxyphene, and dipipanone. Similarly, Diconal is a combination drug containing dipipanone and cyclizine.[citation needed
]

Synthesis

(4-Chlorophenyl)-phenylmethanol is halogenated with thionyl chloride before adding acetylpiperazine. The acetyl group is cleaved with diluted sulfuric acid. An N-alkylation of the piperazine ring with 3-methylbenzylchloride completes the synthesis.[19]

Alternatively, the last step can be replaced by a reductive N-alkylation with 3-methylbenzaldehyde. The reductive agent is

catalyst.[20][21]

Meclizine is obtained and used as a

stereoisomers. Drug forms contain the racemic dihydrochloride.[citation needed
]

Names

Meclizine is an international nonproprietary name.[22]

It is sold under the brand names Bonine, Bonamine, Antivert, Postafen, Sea Legs, and Dramamine II (Less Drowsy Formulation). Emesafene is a combination of meclizine (1/3) and

nicotinic acid.[23]

Notes

  1. ^ "[C]atalepsy was assessed by the bar method[:] the front paws were gently placed on a horizontal metal bar with 2 mm diameter suspended 4 cm above, and the length of time the mouse maintains this abnormal posture was measured."[18]

References

  1. ^ a b c d e f g h "Meclizine Hydrochloride Monograph for Professionals". Drugs.com. American Society of Health-System Pharmacists. Retrieved 22 March 2019.
  2. ^ "Meclizine Use During Pregnancy". Drugs.com. Retrieved 3 March 2019.
  3. ISBN 9783527607495
    .
  4. ISBN 9783318056372
    .
  5. ^ "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.
  6. ^ "Meclizine - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.
  7. ^
    PMID 32809480
    .
  8. ^ "Drugs & Medications". www.webmd.com. Retrieved 28 December 2018.
  9. ^ "Antiemetische Therapie bei Schwangerschaftserbrechen" [Antiemetic therapy in pregnancy]. Arznei-Telegramm (in German). 40: 87–89. 2009.
  10. ^ "Meclozin" [Federal Ministry of Health]. Embryotox (in German). Bundesministerium für Gesundheit.
  11. ^ Lawson BD, McGee HA, Castaneda MA, Golding JF, Kass SJ, McGrath CM (2 December 2009). "Evaluation of several common antimotion sickness medications and recommendations concerning their potential usefulness during special operations". Pensacola, Florida: Naval Aerospace Research Lab. Archived from the original on 27 April 2016. Retrieved 7 February 2016.
  12. S2CID 3987838
    .
  13. PMID 31643231
    .
  14. S2CID 40691502
    .
  15. ^ "Meclizine - oral, Antivert, D-vert, Dramamine II". MedicineNet. Retrieved 7 November 2010.
  16. ^ "Meclizine". Drug Information Provided by Lexi-Comp. January 2010. Archived from the original on 22 August 2009. Retrieved 7 November 2010 – via Merck Manuals, Online Medical Library.
  17. PMID 32077140
    .
  18. ^
    PMID 9193868. Archived from the original
    on 28 August 2021. Retrieved 12 June 2014.
  19. ISBN 978-3-527-30272-7
    .
  20. ^ US 2709169, Morren H, issued 24 May 1955, assigned to Union Chimique Belge Société Anonyme 
  21. ISBN 3-13-115134-X
    .
  22. ^ "Guidelines on the Use of INNs for Pharmaceutical Substances" (PDF). WHO. 1997. Retrieved 1 November 2013.
  23. ^ Wishard D. "Drug card for Meclizine". DrugBank. Canada: University of Alberta. Retrieved 7 November 2010.