The LD50 of nicotine
is 50 mg/kg for rats and 3 mg/kg for mice. 40–60 mg (0.5-1.0
mg/kg) can be a lethal dosage for adult humans. This makes it an
extremely deadly poison. It is more toxic than many other
alkaloids such as cocaine, which has an LD50 of 95.1 mg/kg when
administered to mice.
The carcinogenic properties of nicotine in standalone form,
separate from tobacco smoke, have not been evaluated by the IARC,
and it has not been assigned to an official carcinogen group.
The currently available literature indicates that nicotine, on
its own, does not promote the development of cancer in healthy
tissue and has no mutagenic properties. Its teratogenic
properties have not yet been adequately researched, and while
the likelihood of birth defects caused by nicotine is believed
to be very small or nonexistent, nicotine replacement product
manufacturers recommend consultation with a physician before
using a nicotine patch or nicotine gum while pregnant or
nursing. However, nicotine and the increased cholinergic
activity it causes have been shown to impede apoptosis, which is
one of the methods by which the body destroys unwanted cells
(programmed cell death). Since apoptosis helps to remove mutated
or damaged cells that may eventually become cancerous, the
inhibitory actions of nicotine create a more favourable
environment for cancer to develop. Thus nicotine plays an
indirect role in carcinogenesis. It is also important to note
that its addictive properties are often the primary motivating
factor for tobacco smoking, contributing to the proliferation of
cancer.
At least one study has concluded that exposure to nicotine
alone, not simply as a component of cigarette smoke, could be
responsible for some of the neuropathological changes observed
in infants dying from Sudden Infant Death Syndrome (SIDS).
It has been noted that the majority of people diagnosed with
schizophrenia smoke tobacco. Estimates for the number of
schizophrenics that smoke range from 75% to 90%. It was recently
argued that the increased level of smoking in schizophrenia may
be due to a desire to self-medicate with nicotine. More recent
research has found the reverse, that it is a risk factor without
long-term benefit, used only for its short term effects.
However, research on nicotine as administered through a patch or
gum is ongoing.
Therapeutic uses >>
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Nicotine
History and name
Chemistry
Pharmacology
1.Pharmacokinetics
2.Pharmacodynamics
2.1 In adrenal medulla
2.2 In CNS
Psychoactive effects
Dependence
Toxicology
Therapeutic uses
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