Tacrine

Tacrine is a centrally acting acetylcholinesterase inhibitor and indirect cholinergic agonist (parasympathomimetic). It was the first centrally acting cholinesterase inhibitor approved for the treatment of Alzheimer's disease, and was marketed under the trade name Cognex. Tacrine was first synthesised by Adrien Albert at the University of Sydney in 1949. It also acts as a histamine N-methyltransferase inhibitor.[1]

## Contents

* 1 Clinical use
* 2 Adverse effects
* 2.1 Overdose
* 3 Pharmacokinetics
* 4 References
* 5 External links

## Clinical use

Tacrine was the prototypical cholinesterase inhibitor for the treatment of Alzheimer's disease. William K. Summers received a patent for this use in 1989.[2][3][4] Studies found that it may have a small beneficial effect on cognition and other clinical measures, though study data was limited and the clinical relevance of these findings was unclear.[5][6]

Tacrine has been discontinued in the US[7] in 2013, due to concerns over safety.[8]

Tacrine was also described as an analeptic agent used to promote mental alertness.[9]

## Adverse effects

Very common (>10% incidence) adverse effects include[7]

* Increased liver function tests (LFT), with 49% of patients displaying elevated ALA[10]
* Diarrhea
* Dizziness
* Headache
* Nausea
* Vomiting

Common (1-10% incidence) adverse effects include[7][11]

* Abdominal pain
* Agitation
* Anxiety
* Ataxia — decreased control over bodily movements.
* Belching
* Confusion
* Conjunctivitis (a link to tacrine treatment has not been conclusively proven)
* Constipation
* Diaphoresis — sweating.
* Fatigue
* Hallucinations
* Indigestion
* Insomnia
* Myalgia — muscle pain
* Rash
* Rhinitis
* Somnolence
* Tremor
* Urinary incontinence
* Weight loss

Uncommon/rare (<1% incidence) adverse effects include[11]

* Agranulocytosis (a link between treatment and this adverse effect has not been proven) — a potentially fatal drop in white blood cells, the body's immune/defensive cells.
* Hepatotoxicity (that is toxic effects on the liver)
* Ototoxicity (hearing/ear damage; a link to tacrine treatment has not been conclusively proven)
* Seizures
* Taste changes

Unknown incidence adverse effects include[11]

* Bradycardia
* Delirium
* Depression
* Hypotension
* Suicidal ideation and behaviour
* Urinary tract infection
* Other optic effects such as glaucoma, cataracts, etc. (also not conclusively linked to tacrine treatment)

### Overdose

As stated above, overdosage of tacrine may give rise to severe side effects such as nausea, vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Atropine is a popular treatment for overdose.[11]

## Pharmacokinetics

Major form of metabolism is in the liver via hydroxylation of benzylic carbon by CYP1A2. This forms the major metabolite 1-hydroxy-tacrine (velnacrine) which is still active.[11]

## References

1. ↑ "Actions of tacrine and galanthamine on histamine-N-methyltransferase". Methods and Findings in Experimental and Clinical Pharmacology 27 (3): 161–165. April 2005. doi:10.1358/mf.2005.27.3.890872. PMID 15834447.
2. ↑ Summers WK, "Administration of monoamine acridines in cholinergic neuronal deficit states", US patent 4816456, issued 28 March 1989
3. ↑ "﻿A Psychiatrist's work leads to a US study of Alzheimer's drug: but Dr. Summers shuns test, seeks to widen his own; is Memory really aided; Fee-for research Furor﻿". Wall Street Journal: A-1. 4 August 1987.
4. ↑ "New Mexico Doctor invents drugs, supplements for Alzheimer's disease, Multiple Sclerosis.". NM Bus Weekly. 25 March 2005. https://www.bizjournals.com/albuquerque/stories/2005/03/28/smallb2.html.
5. ↑ "Cholinesterase inhibition for Alzheimer disease: a meta-analysis of the tacrine trials. Dementia Trialists' Collaboration". JAMA 280 (20): 1777–1782. November 1998. doi:10.1001/jama.280.20.1777. PMID 9842955.
6. ↑ Pharmacology (5th ed.). Edinburgh: Churchill Livingstone. 2003. ISBN 978-0-443-07145-4. .
7. ↑ 7.0 7.1 7.2 "tacrine (Discontinued) - Cognex". Medscape Reference. WebMD. http://reference.medscape.com/drug/tacrine-343070.
8. ↑ "Tacrine". LiverTox. U.S. National Institutes of Health. http://www.livertox.nih.gov/Tacrine.htm.
9. ↑ Dictionary of Drugs. 1990. doi:10.1007/978-1-4757-2085-3. ISBN 978-1-4757-2087-7.
10. ↑ "Hepatotoxic effects of tacrine administration in patients with Alzheimer's disease". JAMA 271 (13): 992–998. April 1994. doi:10.1001/jama.1994.03510370044030. PMID 8139084.
11. ↑ 11.0 11.1 11.2 11.3 11.4 Truven Health Analytics, Inc. DRUGDEX® System (Internet) [cited 2013 Oct 8]. Greenwood Village, CO: Thomsen Healthcare; 2013.

## External links

* Acetylcholinesterase: A gorge-ous enzyme QUite Interesting PDB Structure article at PDBe

* v
* t
* e

Psychoanaleptics: Anti-dementia agents (ATC code N06D and others)

AChE inhibitor medications|

* Donepezil
* Galantamine
* Ipidacrine
* Rivastigmine
* Tacrine

Other medications|

* Bifemelane
* Ginkgo folium
* Meclofenoxate (centrophenoxine)
* Memantine
* Nicergoline

Experimental BACE inhibitors|

* Lanabecestat
* Verubecestat

* v
* t
* e

Acetylcholine metabolism and transport modulators

Enzyme
(modulators)|

| ChAT|

* Inhibitors: 1-(-Benzoylethyl)pyridinium
* 2-(α-Naphthoyl)ethyltrimethylammonium
* 3-Chloro-4-stillbazole
* 4-(1-Naphthylvinyl)pyridine
* Acetylseco hemicholinium-3
* Acryloylcholine
* AF64A
* B115
* BETA
* CM-54,903
* N,N-Dimethylaminoethylacrylate
* N,N-Dimethylaminoethylchloroacetate

|

AChE|

* Inhibitors: Reversible: Carbamates: Aldicarb
* Aminocarb
* Bendiocarb
* Bufencarb
* Carbaryl
* Carbendazim
* Carbetamide
* Carbofuran
* Carbosulfan
* Chlorbufam
* Chloropropham
* Dimetilan
* Ethienocarb
* Ethiofencarb
* Fenobucarb
* Formetanate
* Formparanate
* Methiocarb
* Methomyl
* Metolcarb
* Miotine
* Oxamyl
* Phenmedipham
* Pinmicarb
* Pirimicarb
* Propamocarb
* Propham
* Propoxur
* Thiofanox; Stigmines: Distigmine
* Eptastigmine
* Ganstigmine
* Neostigmine
* Phenserine
* Physostigmine
* Pyridostigmine
* Quilostigmine
* Rivastigmine
* Terestigmine; Others: Acotiamide
* Ambenonium
* Caffeine
* Donepezil
* EA-3990
* EA-4056
* Edrophonium
* Galantamine
* Huperzine A
* Ipidacrine
* Itopride
* Ladostigil
* Minaprine
* Octamethylene-bis(5-dimethylcarbamoxyisoquinolinium bromide)
* T-1123
* TL-599
* TL-1238
* Tacrine
* Zanapezil

* Irreversible: Organophosphates: 2-Ethoxycarbonyl-1-methylvinyl cyclohexyl methylphosphonate
* Acephate
* Anatoxin-a(S)
* Armine
* Azinphos-ethyl
* Azinphos-methyl
* BAY-29952
* Bensulide
* Cadusafos
* Carbophenothion
* Chlorethoxyfos
* Chlorfenvinphos
* Chlorpyrifos
* Chlorpyrifos-methyl
* Coumaphos
* Crotylsarin
* Cyanophos
* Cyclosarin (GF)
* Demephion
* Demeton
* Demeton-S-methyl
* Dialifor
* Diazinon
* Dichlorvos
* Dicrotophos
* Diisopropyl fluorophosphate
* Diisopropylphosphate
* Dimefox
* Dimethoate
* Dimethyl 4-(methylthio)phenyl phosphate
* Dioxathion
* Disulfoton
* EA-2012
* EA-2054
* EA-2098
* EA-2192
* EA-2613
* EA-3148
* EA-4352
* Echothiophate
* Ethylsarin (GE)
* Endothion
* Ethion
* Ethoprop
* Fenamiphos
* Fenitrothion
* Fenthion
* Fluorotabun
* Fonofos
* Formothion
* Fosthiazate
* GD-42
* GH
* GT-45
* GV
* Hexaethyl tetraphosphate
* Isofluorophate
* Isoxathion
* Leptophos
* Malaoxon
* Malathion
* Methamidophos
* Methidathion
* Methyl phenkapton
* Methylfluorophosphonylcholine (MFPCh)
* Metrifonate
* Mevinphos
* Mipafox
* Monocrotophos
* Naled
* Novichok agent
* Omethoate
* Oxydemeton-methyl
* Paraoxon
* Parathion
* Parathion-methyl
* Phorate
* Phosalone
* Phosfolan
* Phosmet
* Phosphamidon
* Phoxim
* Pirimiphos-methyl
* Profenofos
* Prothoate
* Ro 3-0340
* Ro 3-0346
* Ro 3-0347
* Ro 3-0351
* Ro 3-0352
* Ro 3-0397
* Ro 3-0411
* Ro 3-0412
* Ro 3-0417
* Ro 3-0419
* Ro 3-0422
* Ro 3-0433
* Sarin (GB)
* Schradan
* Soman (GD)
* Tabun (GA)
* Tebupirimfos
* Temefos
* Terbufos
* Tetrachlorvinphos
* Tetraethyl pyrophosphate
* Triazofos
* Tribufos
* Trichlorfon
* Trichloronate
* Tricresyl phosphate
* VE
* VG
* VM
* VP
* VS
* VR
* VX; Others: Demecarium
* Fasciculins (green mamba toxins) (1, 2, 3, 4)
* Onchidal (Onchidella binneyi)
* Methanesulfonyl fluoride

* Unsorted: α-Pinene
* α-Viniferin
* Affinine
* Affinisine
* Arisugacin A
* Bulbocapnine
* Conodurine
* Coronaridine
* Corydaline
* Corynoline
* Crimidine
* Cyclanoline
* Cymserine
* Harmaline
* Kobophenol A
* Lactucopicrin
* Lycorine
* Phosacetim
* Rosmarinic acid
* Stercuronium iodide
* Taspine
* Tetrahydrocannabinol
* Ungeremine
* Ungiminorine
* Dimethylcarbamoyl fluoride
* BW284C51

* Reactivators: Asoxime chloride
* Methoxime
* Obidoxime
* Pralidoxime
* Trimedoxime bromide

BChE|

* Inhibitors: Affinine
* Affinisine
* Conodurine
* Cymserine
* Ladostigil
* Profenamine (ethopropazine)
* Rivastigmine
* Tacrine
* ZINC-12613047
* Many of the other AChE inhibitors listed above

Transporter
(modulators)|

| CHT|

* Inhibitors: Hemicholinium-3 (hemicholine)
* Triethylcholine

* Enhancers: Coluracetam

|

VAChT|

* Inhibitors: Vesamicol

Release
(modulators)|

| Inhibitors|

* SNAP-25 inactivators: Botulinum toxin (A, C, E)

* VAMP inactivators: Botulinum toxin (B, D, F, G)

* Others: [[Chemistry:BungaroBungarotoxins (Beta-Bungarotoxin|β-bungarotoxin]], γ-bungarotoxin)

|

Enhancers|

* LPHN agonists: α-Latrotoxin

* Others: Atracotoxins (e.g., robustoxin, versutoxin)
* Crotoxin

See also: Receptor/signaling modulators • Muscarinic acetylcholine receptor modulators • Nicotinic acetylcholine receptor modulators

* v
* t
* e

Monoamine metabolism [[Biology:Enzyme modulator

Non-specific|

| AAAD|

* Substrates→Products: L-DOPA (levodopa)→Dopamine
* 5-HTP→Serotonin
* L-Histidine→Histamine
* [[Chemistry:PhenylPhenylalanine→Phenethylamine|Phenethylamine]]
* L-Tyrosine→Tyramine
* Tryptophan→Tryptamine

* Inhibitors: Benserazide
* Carbidopa
* DFMD
* Genistein
* Methyldopa

|

MAO|

* Substrates→Products (with ALDH/ALR): Epinephrine (adrenaline)→DHMA
* Metanephrine→MHPG/VMA
* Norepinephrine (noradrenaline)→DHMA
* Normetanephrine→MHPG/VMA
* Dopamine→DOPAC
* 3-Methoxytyramine→HVA
* Serotonin→5-HIAA

* Inhibitors: Non-selective: Benmoxin
* Caroxazone
* Echinopsidine
* Furazolidone
* Guineesine
* Hydralazine
* Indantadol
* Iproclozide
* Iproniazid
* Isocarboxazid
* Isoniazid
* Linezolid
* Mebanazine
* Metfendrazine
* Nialamide
* Octamoxin
* Paraxazone
* Phenelzine
* Pheniprazine
* Phenoxypropazine
* Pivhydrazine
* Procarbazine
* Safrazine
* Tranylcypromine

* Inhibitors: MAO-A-selective: Amiflamine
* Bazinaprine
* Befloxatone
* Brofaromine
* Cimoxatone
* Clorgiline
* CX157 (Tyrima)
* Eprobemide
* Esuprone
* Harmala alkaloids (e.g., harmine, harmaline, harman]], norharman, tetrahydroharmine)
* Methylene blue
* Metralindole
* Minaprine
* Moclobemide
* Pirlindole
* Sercloremine
* Tetrindole
* Toloxatone

* Inhibitors: MAO-B selective: Adarigiline
* Almoxatone
* D-Deprenyl
* Ethanol
* Ladostigil
* Lazabemide
* Milacemide
* Mofegiline
* Nicotine
* Pargyline‡
* Rasagiline
* Safinamide
* Selegiline (L-Deprenyl)
* Sembragiline

Phenethylamines
(dopamine, epinephrine]],
norepinephrine)</small>|

| PAH|

* Substrates→Products: [[Chemistry:PhenylPhenylalanine]]→Tyrosine

* Inhibitors: 3,4-Dihydroxystyrene

|

TH|

* Substrates→Products: Tyrosine→L-DOPA (levodopa)

* Inhibitors: 2-Hydroxyestradiol
* 2-Hydroxyestrone
* 3-Iodotyrosine
* Aquayamycin
* Bulbocapnine
* Metirosine
* Oudenone

DBH|

* Substrates→Products: Dopamine→Norepinephrine (Noradrenaline)

* Inhibitors: Bupicomide
* Disulfiram
* Dopastin
* Fusaric acid
* Nepicastat
* Phenopicolinic acid
* Tropolone

PNMT|

* Substrates→Products: Norepinephrine (noradrenaline)→Epinephrine (adrenaline)

* Inhibitors: CGS-19281A
* SKF-64139
* SKF-7698

COMT|

* Substrates→Products: Dopamine→3-Methoxytyramine
* DOPAC→Homovanillic acid
* Norepinephrine→Normetanephrine
* Epinephrine→Metanephrine
* DOPEG→MOPEG
* DOMA→VMA
* 2-Hydroxyestradiol→2-Methoxyestradiol
* [[Chemistry:2-Hydroxy2-Hydroxyestrone]]→2-Methoxyestrone
* 4-Hydroxyestradiol→4-Methoxyestradiol
* [[Chemistry:4-Hydroxy4-Hydroxyestrone]]→4-Methoxyestrone

* Inhibitors: 2-Hydroxyestradiol
* 2-Hydroxyestrone
* Entacapone
* Neluxicapone
* Nitecapone
* Opicapone
* Tolcapone

Tryptamines
(serotonin, melatonin)|

| TPH|

* Substrates→Products: Tryptophan→5-HTP

* Inhibitors: AGN-2979
* Fenclonine (PCPA)
* Telotristat ethyl

|

AANAT|

* Substrates→Products: Serotonin→N-Acetylserotonin

ASMT|

* Substrates→Products: N-Acetylserotonin→Melatonin

Histamine|

| HDC|

* Substrates→Products: L-Histidine→Histamine

* Inhibitors: Catechin
* Alpha-Fluoromethylhistidine
* Histidine methyl ester
* Meciadanol
* Naringenin
* Tritoqualine

|

HNMT|

* Substrates→Products: Histamine→N-Methylhistamine

* Inhibitors: Amodiaquine
* Diphenhydramine
* Harmaline
* Metoprine
* Quinacrine
* SKF-91488
* Tacrine

DAO|

* Substrates→Products: Histamine→Imidazole acetic acid

* Inhibitors: Pimagedine (aminoguanidine)

See also: Receptor/signaling modulators • Adrenergics • Dopaminergics • Melatonergics • Serotonergics • Monoamine reuptake inhibitors • Monoamine releasing agents • Monoamine neurotoxins

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Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Tacrine&oldid=4178025"
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template
*[ChAT]: Choline acetyltransferase
*[AChE]: Acetylcholinesterase
*[BChE]: Butyrylcholinesterase
*[CHT]: Choline transporter
*[VAChT]: Vesicular acetylcholine transporter
*[SNAP-25]: Synaptosomal-associated protein 25
*[VAMP]: Vesicle-associated membrane protein
*[LPHN]: Latrophilin
*[AAAD]: Aromatic L-amino acid decarboxylase
*[MAO]: Monoamine oxidase
*[ALDH]: Aldehyde dehydrogenase
*[ALR]: Aldehyde reductase
*[PAH]: Phenylalanine hydroxylase
*[TH]: Tyrosine hydroxylase
*[DBH]: Dopamine beta-monooxygenase
*[PNMT]: Phenylethanolamine N-methyltransferase
*[COMT]: Catechol-O-methyl transferase
*[TPH]: Tryptophan hydroxylase
*[AANAT]: Serotonin N-acetyl transferase
*[ASMT]: Acetylserotonin O-methyltransferase
*[HDC]: Histidine decarboxylase
*[HNMT]: Histamine N-methyltransferase
*[DAO]: Diamine oxidase