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Cyclizine


Cyclizine
Systematic (IUPAC) name
1-benzhydryl-4-methyl-piperazine
Identifiers
CAS number	82-92-8
ATC code	R06AE03
PubChem	6726
DrugBank	APRD00061
Chemical data
Formula	C₁₈H₂₂N₂
Mol. mass	266.381 g/mol
SMILES	search in eMolecules, PubChem
Pharmacokinetic data
Bioavailability	?
Metabolism	N-demethylated to inactive norcyclizine
Half life	20 hours
Excretion	?
Therapeutic considerations
Pregnancy cat.	A (Au)
Legal status	P/POM (UK) OTC (NL)
Routes	Oral, IM, IV

Cyclizine is an antihistamine drug used to treat nausea, vomiting and dizziness associated with motion sickness, vertigo and post-operative following administration of general anaesthesia and opioids.

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1 Pharmacology
2 Contraindications
3 Side effects
4 Formulations
5 Abuse
6 References

Pharmacology

Cyclizine is a piperazine derivative with histamine H₁-receptor antagonist (antihistamine) activity. The precise mechanism of action in inhibiting the symptoms of motion sickness is not well understood. It may have effects directly on the labyrinthine apparatus and on the chemoreceptor trigger zone. Cyclizine exerts a central anticholinergic (antimuscarinic) action.

Contraindications

Its antimuscarinic action warrants caution in patients with prostatic hypertrophy, urinary retention, glaucoma. Liver disease exacerbates its sedative effects. It cannot be combined with diclofenac, for example in the same syringe or bag of fluids, as a crystallisation reaction occurs.

Side effects

Common (>10%) - Drowsiness, xerostomia (dry mouth)

Uncommon (1% to 10%) - Headache, psychomotor impairment, and antimuscarinic effects such as urinary retention, diplopia (blurred vision), dermatitis, and gastro-intestinal disturbances.

Rare - Hypersensitivity reactions (bronchospasm, angioedema, anaphylaxis, rashes and photosensitivity reactions), extrapyramidal effects, dizziness, confusion, depression, sleep disturbances, tremor, liver dysfunction.

Formulations

As cyclizine hydrochloride 50mg tablets and cyclizine lactate solution for intramuscular or intravenous injection (Brand names: Valoid® in UK and Marezine®, Marzine® and Emoquil® in US)).

Abuse

In the UK the drug was removed from the shelves as an OTC preparation in the mid 80s because of it's interaction with opiates. It served to increase the 'flash' of injected opiates. Since opiate users would regularly use high doses, the number of ER room admissions due to seizures became a notable public health risk. Even so, the drug remains available on the internet and pockets of abuse still exist in the UK.

References

British National Formulary 53 2007

Lexi-Online drug database http://online.lexi.com/crlsql/servlet/crlonline

v • d • e Antihistamines (primarily R06)
Aminoalkyl ethers	Bromazine • Carbinoxamine • Clemastine • Chlorphenoxamine • Diphenylpyraline • Diphenhydramine • Doxylamine • Orphenadrine • Phenyltoloxamine
Substituted alkylamines	Brompheniramine • Chlorphenamine • Dexbrompheniramine • Dexchlorpheniramine • Dimetindene • Pheniramine • Talastine
Substituted ethylenediamines	Chloropyramine • Histapyrrodine • Mepyramine • Methapyrilene • Tripelennamine (Pyribenzamine)
Phenothiazine derivatives	Alimemazine • Hydroxyethylpromethazine • Isothipendyl • Mequitazine • Methdilazine • Oxomemazine • Promethazine
Piperazine derivatives	Buclizine • Cetirizine • Chlorcyclizine • Cinnarizine • Cyclizine • Hydroxyzine • Levocetirizine • Meclizine • Niaprazine • Oxatomide
Others for systemic use	Antazoline • Azatadine • Bamipine • Cyproheptadine • Deptropine • Dimebon • Ebastine • Epinastine • Ketotifen • Mebhydrolin • Mizolastine • Phenindamine • Pimethixene • Pyrrobutamine • Rupatadine • Triprolidine • selective (Acrivastine • Astemizole • Azelastine • Desloratadine • Fexofenadine • Loratadine • Terfenadine)
For topical use	Bamipine • Chloropyramine • Chlorphenoxamine • Clemastine • Dimetindene • Diphenhydramine • Isothipendyl • Mepyramine • Promethazine • Thenalidine
Antiallergic agents excluding corticosteroids	Antazoline • Azelastine
Other antiallergics	Emedastine • Epinastine • Ketotifen • Olopatadine

v • d • e Deliriants (anticholinergic hallucinogens)
Tropanes	Atropine, Hyoscyamine, Scopolamine
Benzilates	Benactyzine, Dicyclomine, N-Ethyl-3-piperidyl benzilate, N-Methyl-3-piperidyl benzilate, 3-Quinuclidinyl benzilate
Antihistamines	Cyclizine, Dimenhydrinate, Diphenhydramine, Doxylamine, Promethazine
Others	Benzydamine, Biperiden, Trihexyphenidyl

Categories: Antihistamines | Antiemetics

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cyclizine". A list of authors is available in Wikipedia.