Cyclizine

Cyclizine

Clinical data
Trade names	Marezine, Valoid, Nausicalm, others
AHFS/Drugs.com	Consumer Drug Information
Pregnancy category	AU: A
Routes of administration	By mouth, IM, IV
ATC code	R06AE03 (WHO)
Legal status
Legal status	AU: S3 (Pharmacist only) UK: P (Pharmacy medicines) US: OTC OTC (Netherlands)
Pharmacokinetic data
Metabolism	N-demethylated to inactive norcyclizine
Elimination half-life	20 hours
Identifiers
IUPAC name 1-benzhydryl-4-methyl-piperazine
CAS Number	82-92-8 Y
PubChem CID	6726
IUPHAR/BPS	7151
DrugBank	DB01176 Y
ChemSpider	6470 Y
UNII	QRW9FCR9P2
KEGG	D03621 Y
ChEBI	CHEBI:3994 Y
ChEMBL	ChEMBL648 Y
CompTox Dashboard (EPA)	DTXSID4022864
ECHA InfoCard	100.001.314
Chemical and physical data
Formula	C18H22N2
Molar mass	266.388 g·mol−1
3D model (JSmol)	Interactive image
SMILES CN(CC1)CCN1C(C2=CC=CC=C2)C3=CC=CC=C3
InChI InChI=1S/C18H22N2/c1-19-12-14-20(15-13-19)18(16-8-4-2-5-9-16)17-10-6-3-7-11-17/h2-11,18H,12-15H2,1H3 Y Key:UVKZSORBKUEBAZ-UHFFFAOYSA-N Y
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Cyclizine, sold under a number of brand names, is a medication used to treat and prevent nausea, vomiting and dizziness due to motion sickness or vertigo. It may also be used for nausea after general anaesthesia or that which developed from opioid use. It is taken by mouth, in the rectum, or injected into a vein.

Common side effects include sleepiness, dry mouth, constipation, and trouble with vision. More serious side effects include low blood pressure and urinary retention. It is not generally recommended in young children or those with glaucoma. Cyclizine appears to be safe during pregnancy but has not been well studied. It is in the anticholinergic and antihistamine family of medications.

Cyclizine was discovered in 1947. It is on the World Health Organization's List of Essential Medicines. In the United States it is available over the counter.

Medical uses

Primary uses include nausea, vomiting and dizziness associated with motion sickness, vertigo and post-operatively following administration of general anesthesia and opioids. It is sometimes given in hyperemesis gravidarum, although the manufacturer advises that it be avoided in pregnancy. Off-license use often occurs with specialists in hospitals to treat inpatients who have become severely dehydrated in pregnancy. An off-label use is as an opioid/opiate potentiator.

The drug Diconal is a combination of cyclizine and the opioid dipipanone. Dipipanone is a schedule I controlled substance in the US.

Contraindications

Its antimuscarinic action warrants caution in patients with prostatic hypertrophy, urinary retention, or angle-closure glaucoma. Liver disease exacerbates its sedative effects.

Adverse effects

Common (over 10%) — Drowsiness, dry mouth.

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

Rare (less than 1%) — Hypersensitivity reactions (bronchospasm, angioedema, anaphylaxis, rashes and photosensitivity reactions), extrapyramidal effects, dizziness, confusion, depression, sleep disturbances, tremor, liver dysfunction, and hallucinations.

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 vestibular system and on the chemoreceptor trigger zone. Cyclizine exerts a central anticholinergic (antimuscarinic) action.

Synthesis

Cyclizine may be prepared by the Eschweiler–Clarke methylation of diphenylmethylpiperazine or by reaction of benzhydryl bromide with 1-methylpiperazine in acetonitrile to form the hydrobromide salt of the drug.

History

Cyclizine was developed in the American division of pharmacy company Burroughs Wellcome (today GlaxoSmithKline) during a research study involving many drugs of the antihistamine group. Cyclizine was quickly clinically found as a potent and long-acting antiemetic. The company named the substance – or more precisely cyclizine's hydrochloride form which it usually appears in – "marezine hydrochloride" and started to sell it in the United States under trade name Marezine. Selling was begun in France under trade name Marzine in 1965.

The substance received more credit when NASA chose it as a space antiemetic for the first occupied moon flight. Cyclizine was introduced to many countries as a common antiemetic. It is an over-the-counter drug in many countries because it has been well tolerated, although it has not been studied much.

Society and culture

Some people using methadone recreationally combine cyclizine with their methadone dose, a combination that is known to produce strong psychoactive effects. It has also been used recreationally for its anticholinergic effects to induce hallucinations.

It has been used illegally in greyhound racing to sabotage a dog's performance.

Names

As cyclizine hydrochloride tablets and cyclizine lactate solution for intramuscular or intravenous injection (brand names: Valoid in UK and South Africa and Marezine, Marzine and Emoquil in US). Cyclizine was marketed as Bonine for Kids in the US, but was discontinued in 2012, and replaced with meclizine.

Cyclizine derivatives

Structural comparison of cyclizine and related H1 antagonists
Compound	R1	R2
Cyclizine	H	CH3
Chlorcyclizine	Cl	CH3
Meclizine	Cl
Buclizine	Cl
Oxatomide	H
Hydroxyzine	Cl
Cetirizine	Cl

See also

• Cinnarizine

External links

• "Cyclizine". Drug Information Portal. U.S. National Library of Medicine.