Cyclizine
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3 sources
Collated from TripSit, Pharmacology, DrugCentral. Where sources differ (e.g. dosing), Compare shows them side by side.
First generation antihistamine and anticholinergic drug used to combat nausea and vomiting. Causes drowsiness. Like most antihistamines in high doses it induces delirium and vivid realistic hallucinations. Probably uncomfortable and not enjoyable.TS
Oral
Route dataTripSit
| Threshold | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| — | — | 25–50 mg | — | —+ |
| Onset | 10–30 minutes |
|---|---|
| After-effects | 14 hours |
🧬 Receptor activityPHDC
| Target | Action | Affinity | Source | |
|---|---|---|---|---|
| H1 receptor | Antagonist | 8.4 pKi | GTOPDB | TargetH1 receptor ActionAntagonist Affinity8.4 pKi SourceGTOPDB |
| Histamine H1 receptor | — | Ki 4.443 nM | CHEMBL | TargetHistamine H1 receptor Action— AffinityKi 4.443 nM SourceCHEMBL |
| 5-hydroxytryptamine receptor 2A | — | Ki 64 nM | CHEMBL | Target5-hydroxytryptamine receptor 2A Action— AffinityKi 64 nM SourceCHEMBL |
| Muscarinic acetylcholine receptor M4 | — | Ki 119 nM | CHEMBL | TargetMuscarinic acetylcholine receptor M4 Action— AffinityKi 119 nM SourceCHEMBL |
| Muscarinic acetylcholine receptor M3 | — | Ki 159 nM | CHEMBL | TargetMuscarinic acetylcholine receptor M3 Action— AffinityKi 159 nM SourceCHEMBL |
| Muscarinic acetylcholine receptor M1 | — | Ki 163 nM | CHEMBL | TargetMuscarinic acetylcholine receptor M1 Action— AffinityKi 163 nM SourceCHEMBL |
| 5-hydroxytryptamine receptor 2B | — | Ki 238 nM | CHEMBL | Target5-hydroxytryptamine receptor 2B Action— AffinityKi 238 nM SourceCHEMBL |
| Muscarinic acetylcholine receptor M2 | — | Ki 412 nM | CHEMBL | TargetMuscarinic acetylcholine receptor M2 Action— AffinityKi 412 nM SourceCHEMBL |
| Muscarinic acetylcholine receptor M5 | — | Ki 455 nM | CHEMBL | TargetMuscarinic acetylcholine receptor M5 Action— AffinityKi 455 nM SourceCHEMBL |
| 5-hydroxytryptamine receptor 2C | — | Ki 535 nM | CHEMBL | Target5-hydroxytryptamine receptor 2C Action— AffinityKi 535 nM SourceCHEMBL |
| Alpha-2A adrenergic receptor | — | Ki 582 nM | CHEMBL | TargetAlpha-2A adrenergic receptor Action— AffinityKi 582 nM SourceCHEMBL |
| Alpha-1D adrenergic receptor | — | Ki 597 nM | CHEMBL | TargetAlpha-1D adrenergic receptor Action— AffinityKi 597 nM SourceCHEMBL |
| Sodium-dependent dopamine transporter | — | Ki 606 nM | CHEMBL | TargetSodium-dependent dopamine transporter Action— AffinityKi 606 nM SourceCHEMBL |
| D(3) dopamine receptor | — | Ki 1016 nM | CHEMBL | TargetD(3) dopamine receptor Action— AffinityKi 1016 nM SourceCHEMBL |
| Alpha-1B adrenergic receptor | — | Ki 1379 nM | CHEMBL | TargetAlpha-1B adrenergic receptor Action— AffinityKi 1379 nM SourceCHEMBL |
| Unchecked | — | Ki 2088 nM | CHEMBL | TargetUnchecked Action— AffinityKi 2088 nM SourceCHEMBL |
| Histamine H1 receptor (HRH1) | Antagonist | 8.353 Ki | DRUGCENTRAL | TargetHistamine H1 receptor (HRH1) ActionAntagonist Affinity8.353 Ki SourceDRUGCENTRAL |
| 5-hydroxytryptamine receptor 2A (HTR2A) | — | 7.194 Ki | DRUGCENTRAL | Target5-hydroxytryptamine receptor 2A (HTR2A) Action— Affinity7.194 Ki SourceDRUGCENTRAL |
| 5-hydroxytryptamine receptor 2B (HTR2B) | — | 6.623 Ki | DRUGCENTRAL | Target5-hydroxytryptamine receptor 2B (HTR2B) Action— Affinity6.623 Ki SourceDRUGCENTRAL |
| 5-hydroxytryptamine receptor 2C (HTR2C) | — | 6.272 Ki | DRUGCENTRAL | Target5-hydroxytryptamine receptor 2C (HTR2C) Action— Affinity6.272 Ki SourceDRUGCENTRAL |
| Alpha-1B adrenergic receptor (Adra1b) | — | 5.86 Ki | DRUGCENTRAL | TargetAlpha-1B adrenergic receptor (Adra1b) Action— Affinity5.86 Ki SourceDRUGCENTRAL |
| Alpha-1D adrenergic receptor (ADRA1D) | — | 6.224 Ki | DRUGCENTRAL | TargetAlpha-1D adrenergic receptor (ADRA1D) Action— Affinity6.224 Ki SourceDRUGCENTRAL |
| Alpha-2A adrenergic receptor (ADRA2A) | — | 6.235 Ki | DRUGCENTRAL | TargetAlpha-2A adrenergic receptor (ADRA2A) Action— Affinity6.235 Ki SourceDRUGCENTRAL |
| Amine oxidase [flavin-containing] B (MAOB) | — | — | DRUGCENTRAL | TargetAmine oxidase [flavin-containing] B (MAOB) Action— Affinity— SourceDRUGCENTRAL |
| Cytochrome P450 2D6 (CYP2D6) | — | 5.206 IC50 | DRUGCENTRAL | TargetCytochrome P450 2D6 (CYP2D6) Action— Affinity5.206 IC50 SourceDRUGCENTRAL |
| D(3) dopamine receptor (DRD3) | — | 5.993 Ki | DRUGCENTRAL | TargetD(3) dopamine receptor (DRD3) Action— Affinity5.993 Ki SourceDRUGCENTRAL |
| Muscarinic acetylcholine receptor M1 (CHRM1) | — | 6.788 Ki | DRUGCENTRAL | TargetMuscarinic acetylcholine receptor M1 (CHRM1) Action— Affinity6.788 Ki SourceDRUGCENTRAL |
| Muscarinic acetylcholine receptor M2 (CHRM2) | — | 6.385 Ki | DRUGCENTRAL | TargetMuscarinic acetylcholine receptor M2 (CHRM2) Action— Affinity6.385 Ki SourceDRUGCENTRAL |
| Muscarinic acetylcholine receptor M3 (CHRM3) | — | 6.799 Ki | DRUGCENTRAL | TargetMuscarinic acetylcholine receptor M3 (CHRM3) Action— Affinity6.799 Ki SourceDRUGCENTRAL |
| Muscarinic acetylcholine receptor M4 (CHRM4) | — | 6.924 Ki | DRUGCENTRAL | TargetMuscarinic acetylcholine receptor M4 (CHRM4) Action— Affinity6.924 Ki SourceDRUGCENTRAL |
| Muscarinic acetylcholine receptor M5 (CHRM5) | — | 6.342 Ki | DRUGCENTRAL | TargetMuscarinic acetylcholine receptor M5 (CHRM5) Action— Affinity6.342 Ki SourceDRUGCENTRAL |
| Sodium-dependent dopamine transporter (SLC6A3) | — | 6.218 Ki | DRUGCENTRAL | TargetSodium-dependent dopamine transporter (SLC6A3) Action— Affinity6.218 Ki SourceDRUGCENTRAL |
Mechanism of actionPH
Vomiting (emesis) is essentially a protective mechanism for removing irritant or otherwise harmful substances from the upper GI tract. Emesis or vomiting is controlled by the vomiting centre in the medulla region of the brain, an important part of which is the chemotrigger zone (CTZ). The vomiting centre possesses neurons which are rich in muscarinic cholinergic and histamine containing synapses. These types of neurons are especially involved in transmission from the vestibular apparatus to the vomiting centre. Motion sickness principally involves overstimulation of these pathways due to various sensory stimuli. Hence the action of cyclizine which acts to block the histamine receptors in the vomiting centre and thus reduce activity along these pathways. Furthermore since cyclizine possesses anti-cholinergic properties as well, the muscarinic receptors are similarly blocked.
.../IT SEEMS/ THAT STIMULATION OF VESTIBULAR APPARATUS IS NECESSARY & SUFFICIENT...& THAT VESTIBULAR CEREBELLAR MIDBRAIN "INTEGRATIVE VOMITING CENTER" & MEDULLARY CHEMORECEPTIVE TRIGGER ZONE ARE...INVOLVED /IN MOTION SICKNESS/. IT IS...PROBABLE THAT EFFECTIVE ANTIHISTAMINES EXERT.../ACTION/ IN THESE CENTERS. /ANTIHISTAMINE/
PharmacodynamicsPH
Cyclizine is a piperazine-derivative antihistamine used as an antivertigo/antiemetic agent. Cyclizine is used in the prevention and treatment of nausea, vomiting, and dizziness associated with motion sickness. Additionally, it has been used in the management of vertigo in diseases affecting the vestibular apparatus. Although the mechanism by which cyclizine exerts its antiemetic and antivertigo effects has not been fully elucidated, its central anticholinergic properties are partially responsible. The drug depresses labyrinth excitability and vestibular stimulation, and it may affect the medullary chemoreceptor trigger zone. It also possesses anticholinergic, antihistaminic, central nervous system depressant, and local anesthetic effects.
Pharmacokinetics
Half-lifePH
20 hours
AbsorptionPH
BENZHYDROLPIPERAZINES & THEIR N-DEALKYLATION PRODUCTS ARE DISTRIBUTED IN ALL TISSUES OF RAT & ARE TRANSFERRED TO FETUS. /BENZYHYDROLPIPERAZINES/
MetabolismPH
Cyclizine is metabolised to its N-demethylated derivative, norcyclizine, which has little antihistaminic (H1) activity compared to Cyclizine.
OXIDATIVE N-DEALKYLATION IS MAIN METABOLIC PATHWAY OF BENZHYDROLPIPERAZINES; CYCLIZINE.../IS/ TRANSFORMED INTO NORCYCLIZINE...
WITH A PURIFIED MIXED FUNCTION OXIDASE FROM LIVER MICROSOMES IN PRESENCE OF REDUCED PYRIDINE NUCLEOTIDE & O2.../CYCLIZINE IS/ OXIDIZED TO N-OXIDE.
External links
Fact-sheets from PsychonautWiki. Harm-reduction reference only — not medical advice.