Newsgroups: alt.drugs
From: jerry@teetot.acusd.edu (Jerry Stratton)
Subject: Re: Nitrous oxide (be patient)
Message-ID: <1994Jan12.010623.13434@teetot.acusd.edu>
Date: Wed, 12 Jan 94 01:06:23 GMT

[quoted article deleted -cak]

Blow me. Yes, nitrous does 'kill brain cells' although that's a pretty
general statement. Both life and alcohol also kill brain cells. If
you're truly interested in the medical aspects of recreational drugs,
written for laymen, get the following two books, both, as far as I know,
still in print (unlike the wonderful _Licit & Illicit Drugs_, which I
tend to buy whenever I see it, just so I can give it to friends :*)

FROM CHOCOLATE TO MORPHINE: Andrew Weil & Winifred Rosen. Make sure you
get the 1993 edition. It's the one with the horrible sub-title
"Everything You Need To Know About Mind-Altering Drugs". The sub-title's
wrong, but it's still a good reference.

A PRIMER OF DRUG ACTION: Robert M. Julien. I believe it's in the fifth
edition right now, but I don't know.

Here's the kind of stuff you can expect to find in these books:

Robert M. Julien:
"Occasionally, certain anesthetic agents become misused drugs. Nitrous
oxide is an example. A gas of low anesthetic potency, it is incapable of
inducing deep levels of anesthesia if an adequate oxygen concentration
is maintained. Nitrous oxide induces a state of behavioral
disinhibition, analgesia, and euphoria. One of the problems occasionally
encountered when nitrous oxide is used for recreational purposes is
that, unless the compound is administered with at least 20 percent
oxygen, hypoxia (decreased oxygen content of the blood) can be induced.
But in order to achieve high enough concentrations of nitrous oxide to
get a good behavioral effect, concentrations of 50 percent or greater
must be inhaled. If such concentrations are mixed with room air, inhaled
oxygen concentartions drop to low levels and the hypoxia may result in
irreversible brain damage."
(In other words, don't use it in your vw bus :*)

Weil & Rosen:
"Physicians and dentists have long considered nitrous oxide to be a safe
pharmacological agent. Nevertheless, there is some evidence that
excessive or prolonged use of it can damage the bone marrow and nervous
system by interfering with the action of vitamin B-12. Moreover its use
in nonmedical settings presents several hazards that users should keep
in mind. Breathing it directly from pressurized tanks is dangerous for
two reasons. First, gas flowing from such tanks is very cold -- cold
enough to cuase frostbite of noses, lips and (most serious) vocal cords.
Being anesthetized, a user may be unaware of such injuries until too
late. Second, because nitrous oxide does not support life, it should be
mixed with oxygen if it is to be breathed for more than a few minutes.
At private parties, oxygen tanks are rarely supplied, and people have
died of asphyxiation by breathing straight nitrous oxide through face
masks. One way to avoid these dangers is to fill balloons from tanks and
breathe from the balloons.
'Further, nitrous oxide rapidly leads to complete loss of motor control,
and anyone who breathes it while standing will soon reel about and fall
down. Therefore, it is unwise to try the gas unless one is in a
comfortable sitting or lying position. Serious injuries have resulted
from people inhaling laughing gas while standing in front of open
windows, when driving cars (like your dad, HST), or when operating
machinery. Others have been badly hurt by accidentally pulling heavy
tanks of nitrous oxide over onto themselves (it's mine! all mine! you
can't have any!) while intoxicated.
'People who breathe nitrous oxide for more than a few minutes at a time
may experience nausea, especially if they have just eaten. They may also
feel hung over for some time after. Addiction to nitrous oxide is a real
possibility. Addicts may suffer serious mood and personality changes in
addition to the bone marrow and nervous system damage already
mentioned."

Plus, it's lots of fun. (My opinion, again.)

Jerry Stratton
jerry@teetot.acusd.edu (Finger/Reply for PGP Public Key)
------
"Well, if you can't believe what you read in a comic book, what
 *can* you believe?!"
                   --Bullwinkle J. Moose

=============================================================================

From: chris@hacktic.nl (chris)
Newsgroups: alt.drugs
Subject: Nitrous Oxide Dangers
Date: 12 Jan 1994 21:52:13 +0100
Message-ID: <2h1nubINNk66@xs4all.hacktic.nl>

NITROUS   DOES IT KILL BRAIN CELLS?

In an earlier post I mentioned some scientific reports on the possible
dangers of prolonged exposure to nitrous oxide.
This elicited some reactions that focus around the definition of "prolonged
exposure". How much nitrous taken in how much time will rot your nerves?

To get an idea i will transcribe two case reports from a more recent
nitrous horror story. At the same time it will give you an idea what
"neuropathy" and "myeloneuropathy" looks like and what signs to watch out
for when you are a nitrous regular.

From: Stacey et.al (1992) " Methionine in the treatment of nitrous oxide
induced neuropathy and myeloneuropathy" Journal of Neurology 239:401-403.

Case 1 (quote)

This 36-year old electrical engineer came to the emergency room complaining
that he was unable to walk. Symptoms had begun 4 days earlier with "pins
and neeedles" in both feet that gradually worsened and ascended to involve
the knees and the fingertips. With worsening of the paresthesias (-no sense
of touch or pain-) he noted difficulty in maintaining proper control of the
movements of his arms and hands and trouble in walking. He also reported
the sensation of electric shocks through his back and legs upon flexion of
the neck. He denied bladder or bowel impairment but he had been unable to
have an erection for the past week. His past medical history was unremarka-
ble except for occasional abuse of alcohol in the past. However he denied
any drinking of alcohol for the past 8 months.
For recreational purposes he had inhaled two to three boxes of nitrous
oxide, each box containing 24 cartridges, practically every day for the
past six months. 
When first seen his general physical examination was completely unremarka-
ble. The neurological examination showed hyperesthesia and hyperalgesia in
the lower extremities up to the knees. He had severe bilateral sensory
dystaxia and could only stand with support. 
(-More Neurological and Blood statistic Stuff Deleted- ed.).
Intramuscular B12 injections were started and during the following days his
hematological status inproved, (-apart from neurological symptoms, the
functional B12 deficiency caused by N2O also produces megaloblastic
anemia,- ed.)  although his neurological condition continued to deteriora-
te. The paresthesias ascended to the nipples and he developed fecal and
urinary incontinence. (- stuff deleted-)
Four weeks later he began to improve and four months after the onset of the
symptoms, and his last use of nitrous oxide he could walk with some
hesitation and had completely regained bowel and bladder control and sexual
function (-stuff deleted-).

Case 2

This 32 year old woman was admitted tho the neurology service for inability
to walk and paresthesias in her limbs and trunk. Her symptoms began 3 weeks
prior to admission with a "tingling" sensation in the soles of her feet,
trunk and hands. Her gait bexcame progressively less steady and the day
prior to admission she had an episode of urinary incontinence.
Her past medical history was significant for bulimia and occasional
intranasal use of cocaine. for the previous 3 months she had inhaled
nitrous oxide for recreational purposes, up to 200 cartriges a day, three
to four times a week.
(-stuff deleted, similar neurological signs as above, some antisocial
behavior).
(end quote)

What this shows is that these people really did a lot of nitrous, say 300-
400 cartridges a week, for a few months in a row to develop these really
nasty symptoms. But it also shows that people who do such things do exist
( can you believe it?)

For the really health conscious among you (a contradiction in terms?) if
you "must" do nitrous for a longer period be sure to take high doses of
folic acid (is also depleted from your body as a result of functional B12
deficiency ) and vitamin B12. (No injury NOT guaranteed, but it might help)

Also, but less well known, the state of B12 deficiency caused by
regular use of nitrous oxide produces hyperhomocysteinemia, an accumulation
 in the blood of the amino acid homocysteine.
Hyperhomocysteinemia is a risk factor for vascular disease of all sorts.
Furthermore, hyperhomocysteinemia, B12 deficiency and folic acid deficiency
early in pregnancy all increase the risk of getting a child with a neural
tube defect (spina bifida and anencephaly, childeren with no brains or open
spinal cord). If you are a woman, planning to get pregnant or just "at risk
of getting pregnant", nitrous is a bad idea. 
If youre interested in this literature contact me. 

More literature on neurological aspects of nitrous use:

Pulsson (1979) "Recreational" misuse of nitrous oxide, 
J. Am Dent. Soc. 98:410-411
Sahenk et al.(1978) "Polyneuropathy from inhalation of N2O cartridges 
through a whipped cream dispenser" Neurology 28:485-487.

Chris ( chris@hacktic.nl )

=============================================================================

Newsgroups: alt.drugs
From: bagg@ellis.uchicago.edu (matthew john baggott)
Subject: Re: Nitrous.. facts vs. myths
Message-ID: <1993Mar23.214307.19900@midway.uchicago.edu>
Date: Tue, 23 Mar 1993 21:43:07 GMT

[quoted text deleted -cak]

I've been meaning to write up a FAQ about this and have done some
preparatory reading, so I'll take a shot at a first-pass answer:

First, there are the dangers which accompany the inhalation of any
compressed gas (making sure you get enough air, making sure you don't freeze
your lips or inflate your head, making sure you are sitting down and
won't hurt yourself if you get dizzy).

Second, there are the health effects specific to nitrous oxide.  There have
been reports of immunological and reproductive disturbances in professionals
who are chronically exposed to nitrous oxide.  The immunological
disturbances are documented by Peric et al (1991) _Anaethesia_ 46: 531-7.
Apparently anaesthetic personnel had been complaining about
weakness and recurrent infections and decreased peripheral blood
leukocyte counts has been found.  The operating rooms were found to 
be improperly ventilated, causing nitrous oxide and halothane (another
anaesthetic) to remain in the air.  Even after a 3-4 week holiday,
some personnel has decreased B lymphocytes and increased red cell count,
haemoglobin concentration and haematocrit and other disturbances.
I don't have a reference handy for the reproductive disturbances, but the
study basically found that women who were chronically exposed to
nitrous had difficulty becoming pregnant.  It should be noted that these
health effects are the result of CHRONIC exposure; a single balloon at
a Dead show (or a single visit to the dentist) is unlikely to be a problem
for a healthy individual.

Aside from its psychopharmacological actions, nitrous oxide has one other
(known) significant metabolic action: it interacts with vitamin B12.  This
was first reported in an in vitro study in 1968, but didn't really
receive notice from anaesthesiologists until ten years later (because
medline didn't exist yet :-)  ).  In 1978, however, Amess et al showed that 
24 h of nitrous oxide administration caused interference with DNA
synthesis in humans.  Since then, the interaction between nitrous oxide
and B12 has been better characterized.

Basically, B12 is a bound coenzyme of methionine synthase and has a 
tetrapyrrole rings with a monovalent cobalt at the center.  The cobalt
functions as a methyl carrier in a transmethylation reaction.  Nitrous
oxide converts the cobalt from the monovalent form to the bivalent
form.  As a result, methionine synthase activity is inhibited.  Recovery
is believed to require absorption of new unoxidized B12 (and synthesis
of new apoenzyme).

Humans seem to be far more resistant to complications from this than rodents.
I don't have the energy to go through the various published studies at
this point, so I will quote from Nunn's "Clinical Aspects of the Interaction
Between Nitrous Oxide and Vitamin B12" (1987), _Br. J. Anaesth._ 59: 3-13.

	It seems likely that in man, in contrast to the rat, exposure
	of less than 30 minutes will not cause any measurable change in
	methionine synthase activity.  In combination with a wealth of
	clinical experience, this suggests that there is no special
	hazard for short exposures to nitrous oxide.  There is a variable
	response to exposures lasting between 30 minutes and 2 h.  However,
	it now seems likely that exposures of more than 2 h are likely
	to cause intereference with hepatic methionine synthase
	activity.  The paucity of human data makes it more difficult to
	say how long an exposure is required to cause significant
	intereference with DNA synthesis.  It is likely that there will
	be considerable individual variation and results obtained in
	healthy patients cannot be extrapolated to the patient
	who is seriously ill.  Nevertheless, it seems likely that,
	once methionine synthase activity is inhibited, it will remain
	so for days.

With respect to repeated exposures to nitrous, be aware that this effect
can build up (Nunn gives "intervals of less than 3 days" as a cut-off).
So, go easy on the "hippie crack," people!

Mandatory nitrous horror story:  Layzer (in (1978) "Myeloneuropathy after 
prolonged exposure to nitrous oxide," _Lancet_ 2:1227) reports a case of
15 people who had been inhaling nitrous oxide for long periods of time
and developed a condition resembling subacture combined degneration of
the cord, whatever that means.

I would suggest that the following types of people in particular avoid
exposure to signficant amounts of nitrous:

	Pregnant women: since nitrous oxide is a known teratogen in rodents,
	acting by depleting folates and partially reversible by oral
	folinic acid, we can expect a similar syndrome in humans.

	Vegans who don't take B12 supplements: although documented cases of
	vegans with B12 decifiencies are scarce, theories on nutrition
	indicate that vegans are unlikely to get as much B12 as other
	groups of people.

	Individiduals with healing wounds, infections, or immunological
	disorders: I'm throwing this recommendation in based on a "better
	safe than sorry" policy.  Short-term exposure to nitrous oxide
	is unlikely to be a problem, but why not play it safe?

And BTW I did find a reference on sexual ideation during nitrous oxide,
which is a topic that came up some time ago.  More on that when I actually
get the article.

	--Matt Baggott, bagg@midway.uchicago.edu 

>-- 
>   kkwast@cs.utexas.edu (Kevin A. Kwast)     "The computer is your friend."