Nicotinic antagonist

A nicotinic antagonist is a type of anticholinergic drug that inhibits the action of acetylcholine (ACh) at nicotinic acetylcholine receptors. These compounds are mainly used for peripheral muscle paralysis in surgery, the classical agent of this type being tubocurarine,^[1] but some centrally acting compounds such as bupropion, mecamylamine, and 18-methoxycoronaridine block nicotinic acetylcholine receptors in the brain and have been proposed for treating nicotine addiction.^{[medical citation needed]}

Comparison
Mechanism	Antagonist	Preferred receptor	Clinical use
Ganglionic blocking agents	Hexamethonium	Ganglion type	None^[2]
	Mecamylamine	Ganglion type
	Trimethaphan	Ganglion type	Rarely used for blood pressure decrease during surgery^[2]
Nondepolarizing neuromuscular blocking agents	Atracurium	Muscle type	Muscle relaxant in anaesthesia^[2]
	Doxacurium	Muscle type
	Mivacurium	Muscle type
	Pancuronium	Muscle type	Muscle relaxant in anaesthesia^[2]
	Tubocurarine	Muscle type	Discovered in arrow poison it was the first pheripheral muscle relaxant. Rarely used since 1980s.^[2]
	Vecuronium	Muscle type	Muscle relaxant in anaesthesia^[2]
Depolarizing neuromuscular blocking agents	Succinylcholine*	Muscle type
Centrally acting nicotinic antagonists	18-Methoxycoronaridine	α3β4
	Bupropion	α3β4. α4β2, α1β1γδ	Antidepressant (NDRI)
	Hydroxybupropion	α3β4. α4β2, α1β1γδ	Antidepressant (NDRI). Metabolite of bupropion.
	Threohydrobupropion	α3β4.	Antidepressant (NDRI). Metabolite of bupropion.
	Dextromethorphan	α3β4. α4β2, α7	Common over the counter antitussive.
	Dextrorphan	α3β4. α4β2, α7	Metabolite of dextromethorphan; no accepted medical uses.
	3-Methoxymorphinan	α3β4	Secondary metabolite of dextromethorphan; not used in medical practice. Unknown medical efficacy.

Note: Succinylcholine is a nicotinic agonist. See neuromuscular blocking agents page for details on the mechanism of action.

YouTube Encyclopedic

1/5
Views:
640 584
5 735
2 859
21 709
571

Transcription

References

^ P. Taylor (1990). In Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th Ed., (A. G. Gilman et al., Eds.), pp. 166-186, New York: Pergamon Press.
^ ^a ^b ^c ^d ^e ^f Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. ISBN 0-443-07145-4. Page 149

External links

Media related to Nicotinic antagonists at Wikimedia Commons
Nicotinic+antagonists at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

Pharmacomodulation

Types

♦ Enzyme: Inducer
Inhibitor

♦ Ion channel: Opener
Blocker

♦ Transporter [Reuptake vs Efflux]: Enhancer (RE)
Inhibitor (RI)
Releaser (RA)

♦ Miscellaneous: Precursor
Cofactor

Classes

Enzyme

see Enzyme inhibition

Ion channel

See Ion channel modulators

Receptor &
transporter

BA/M

Adrenergic	Adrenergic receptor agonist (α β (1 2)) Adrenergic receptor antagonist (α (1 2) β) Norepinephrine reuptake inhibitor (NRI)
Dopaminergic	Dopamine receptor agonist Dopamine receptor antagonist Dopamine reuptake inhibitor (DRI)
Histaminergic	Histamine receptor agonist Histamine receptor antagonist (H₁ H₂ H₃)
Serotonergic	Serotonin receptor agonist Serotonin receptor antagonist (5-HT₃) Serotonin reuptake inhibitor (SRI)

GABAergic	GABA receptor agonist GABA receptor antagonist GABA reuptake inhibitor (GRI)
Glutamatergic	Glutamate receptor agonist (AMPA) Glutamate receptor antagonist (NMDA) Glutamate reuptake inhibitor

Cholinergic

Cannabinoidergic

Cannabinoid receptor agonist
Cannabinoid receptor antagonist
Endocannabinoid enhancer (eCBE)
Endocannabinoid reuptake inhibitor (eCBRI)

Opioidergic

Other

Miscellaneous

Cofactor (see Enzyme cofactors)
Precursor (see Amino acids)

Medical uses

v t e Treatment of drug dependence (N07B)
Nicotine dependence	Bupropion^# Cytisine Lobeline Mecamylamine Varenicline AATooltip Adrenergic agonist (Clonidine)
Alcohol dependence	AD inhibitor (Disulfiram Calcium carbimide Hydrogen cyanamide) Acamprosate Opioid antagonists Naltrexone Nalmefene Topiramate AATooltip Adrenergic agonist (Clonidine) Baclofen Phenibut
Opioid dependence	AATooltip Adrenergic agonist (Clonidine Lofexidine) Ibogaine Opioids Buprenorphine (+naloxone) Levacetylmethadol Methadone Dihydrocodeine Dihydroetorphine Hydromorphone (extended-release) Morphine (extended-release) Opioid antagonists (Naltrexone Nalmefene)
Benzodiazepine dependence	AATooltip Adrenergic agonist (Clonidine) Benzodiazepines (Diazepam Lorazepam Chlordiazepoxide Oxazepam) Barbiturates (Phenobarbital)

Sympatholytic (and closely related) antihypertensives (C02)

Sympatholytics
(antagonize α-adrenergic
vasoconstriction)

Central

α₂-Adrenergic receptor agonists	Clonidine Guanabenz Guanfacine Guanoxabenz Methyldopa^# Tiamenidine^‡
Adrenergic release inhibitors	Bethanidine Bretylium Debrisoquine Guanadrel Guanazodine Guancydine Guanethidine Guanoclor Guanoxan
Imidazoline receptor agonists	Moxonidine Rilmenidine Tolonidine
Ganglion-blocking/nicotinic antagonists	Hexamethonium^‡ Mecamylamine Pentolinium Trimethaphan

Peripheral

Indirect

Monoamine oxidase inhibitors	Pargyline^‡
VMAT inhibitors	Bietaserpine Deserpidine Methoserpidine Reserpine Syrosingopine
Tyrosine hydroxylase inhibitors	Metirosine

Direct

α₁-Adrenergic receptor blockers	Doxazosin Ketanserin Indoramin Prazosin Trimazosin Urapidil
Non-selective α-adrenergic receptor blockers	Phentolamine

Other antagonists

Serotonin receptor antagonists	Ketanserin Lidanserin
Endothelin receptor antagonists (for PHTooltip Pulmonary hypertension)	dual (Bosentan, Macitentan) selective (Ambrisentan, Sitaxentan)

^#WHO-EM
^‡Withdrawn from market
Clinical trials:
- ^†Phase III
- ^§Never to phase III

Skeletal muscle relaxants (M03)

Peripherally acting
(primarily antinicotinic,
NMJ block)

Non-depolarizing

Curare alkaloids	Alcuronium Dimethyltubocurarine Tubocurarine
4° ammonium agents	ultra-short duration: Gantacurium short duration: Rapacuronium Mivacurium Chandonium intermediate duration: Atracurium Cisatracurium Fazadinium Rocuronium Vecuronium long duration: Doxacurium Dimethyltubocurarine Pancuronium Pipecuronium Laudexium Gallamine unsorted: Hexafluronium (Hexafluorenium)

Depolarizing

Choline derivatives: Suxamethonium (Succinylcholine)

Polyalkylene derivatives: Hexamethonium

ACh release inhibitors

Botulinum toxin

Centrally acting

Carbamic acid esters	Carisoprodol Cyclarbamate Difebarbamate Febarbamate Meprobamate Phenprobamate Styramate Tybamate
Benzodiazepines	Bromazepam Diazepam Clonazepam Flunitrazepam Lorazepam Nitrazepam Temazepam Tetrazepam
Nonbenzodiazepines	Eszopiclone
Thienodiazepines	Etizolam
Quinazolines	Methaqualone
Anticholinergics (Antimuscarinics)	Cyclobenzaprine Orphenadrine
Other	Arbaclofen placarbil Baclofen Chlormezanone Chlorphenesin Chlorzoxazone Eperisone Fenyramidol Flopropione Gabapentin GHB Inaperisone Lanperisone Mephenesin Mephenoxalone Metaxalone Methocarbamol Phenibut Pregabalin Pridinol Promoxolane Quinine Silperisone Thiocolchicoside Tizanidine Tolperisone Zoxazolamine