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What Are The Side Effects Of Nitrous Oxide?

Posted on Fri, 4 Apr 2014

Question: I had a temp crown put in today. I always have nitrous because of a flashback problem from a very bad procedure when I was 19. Nitrous has always had some effect on me....always. Not this time. Nothing. I told them something was wrong. They assured me that their equipment was working fine and they had the settings as high as they could go safely. If that was the case I should've been higher than a kite and asking them to turn it down. My goal is to prevent a flashback, not slip into the netherworld. When I asked them why it had no effect on that setting they replied that it may be my emotional state is different. What I found confusing is my state was no different than it has been the other times. I look at this as much for their protection as my being relaxed. With my military background and training, a flashback will give everyone a seriously bad day, some worse than others. I've never heard of anyone developing an immunity to nitrous. But I can't figure out how they could have it at it's maximum setting and yet to absolutely no effect. Something is very amiss here

Answered by Dr. Girija Kumari (4 hours later)

Brief Answer: can be due to nitrous oxide.. Detailed Answer: Hi, I’m Dr. Girija, anesthetist. The problem you have faced earlier may be because of nitrous oxide, as it would cause dissociative anesthesia or hallucinations. Nitrous acts on NMDA receptor by weak antagonist action causing mild dissociation of brain body connection, and thus leading to hallucinations, a sort of delirium. However, this is a short-term problem. The history you have given signifies long-term issue. Please mention the present age. There is nothing like immunity from nitrous oxide. May be your health condition and the amount of stress you were in at that time would be the factor which would have caused problem previously but not now. Hope I have cleared your doubt. If you have any queries please feel free to ask. Thank you. Have a good day.

Above answer was peer-reviewed by : Dr. Shanthi.E

Follow up: Dr. Girija Kumari (16 hours later)

My current age is 51. I have had nitrous for many times in the recent past, probably a dozen times in the last two years. Every time I have had some kind of reaction to it's effects. The most recent was about three weeks ago when the did the workup to putting in the temporary crown. In that case it did what it was supposed to and kept me in a relaxed state where I could focus my mind on other things. Other times the mixture was too high and I got tingling in my fingers and felt really strange, almost like I was leaving reality. I was having a dream while awake. In that case I would agree with you that it could cause hallucinations. As soon as they got their hands away from my mouth I advised them to turn it down. Having an analytical mind I tend to ask them what the settings are so that I can compare the differing effects with different mixtures and advise them as to the best setting to start. I believe that the sweet spot is somewhere around a 40/60 (nitrous/oxygen) mix. Depending on my general mood a slightly higher or slightly lower mix will have the same effect. When they told me they had it on it's highest setting I was totally dumbfounded. I know from past experience when they set it at maximum I have undesirable, although not totally unpleasant effects. Another effect that happened Monday was the needle they used to numb the area. Normally under the nitrous it would feel like a pinch unless they directly impacted a nerve. This time it was a strong stinging sensation, which gave me my first clue that something wasn't right. As for my general mood at the time, I would say I was slightly more relaxed due to my recent experience during the last visit plus I was already 4 days into my vacation. My stress level always rises when I sit down in the chair, but that is the same feeling I have gotten every time I sit in the chair. My sleep patterns haven't changed since the last appointment and I had a normal sleep the night before. One change was my weight. I was three pounds lighter at this visit. Neither time was I under the effects of any prescribed drugs nor had I taken any over the counter medication within a couple days of my appointment. Both times my sinuses were clear. Getting back to the effects of the nitrous this time, I felt nothing. It was like I wasn't even using it. That is the only way to describe it accurately. I asked them to take it off since it was having no effect. Usually there is a brief interval after stopping the nitrous where I need to clear my head a little. Again, that didn't happen. There is always a subtle change that I feel when they first start the nitrous. It takes a couple of minutes for me to feel a change happening. That didn't happen either. I can't think of any physiological changes that have occurred (other than the weight loss) in just the few short weeks between appointments. I'm at a total loss to explain this. And to be honest, I'm now suspicious of the dentist I go to at present. What they told me I find extremely difficult to believe considering the lengths I went to to find the appropriate mixture and the sweet spot where I'm not too over or under sedated. Lastly, given this most recent experience, now I seem to feel I need to check my sanity. Go to a lab where they can run different mixtures so I can describe to them what I am feeling (if anything) and have them observe me and write down the results so I know I'm not crazy or something. Things like this where they say I should be flying higher than a kite when I feel absolutely no effects is very disturbing to me. It feels like a paradox. Know any places where I can go where they can do controlled experiments in this area? I really need to know this wasn't just in my mind.

Answered by Dr. Girija Kumari (48 hours later)

Brief Answer: Gone through history- it was because of N2O Detailed Answer: Hi Thank you for providing full information. Let me be clear all the effects described were side effects of nitrous oxide. An ideal setting of oxygen: nitrous oxide is 70:30. Conc of nitrous oxide more than 40 or 45 is known to cause problems. This again depends on person to person and day to day in same person. So it is advisable to increase the conc of nitrous oxide slowly from 30 %to 40%. previous exposure to nitrous oxide and its comfort is noted so that it is easier for your dentist to know how good you respond to that concentration of nitrous oxide. Again tolerance is a problem. Some experience tolerance to N2O over time requiring higher conc. What you had done was good. You had noted down the conc and asked your dentist to keep the same mixture, may be you got tolerated to that conc. Your dentist would have tried increasing the conc to 40:60. So all the problems and bad experiences was the result. Depending on the concentration and length of administration of N2O, four levels of sedation can be experienced (after an initial feeling of light-headedness): 1.a tingling sensation, especially in the arms and legs, or a feeling of vibration (parasthesia), quickly followed by 2.warm sensations, and 3.a feeling of well-being, euphoria and/or floating. During heavier sedation, hearing may dissolve into a constant, electronic-like throbbing. 4.At a deeper level of sedation again, sleepiness, difficulty to keep one’s eyes open or speak (dream) can occur. Should nausea set in, it means you’re definitely over sedated! If you experience any unpleasant symptoms, let your dentist know so that they can adjust the percentage of N2O. Alternatively, just take the mask off. The “dream” stage means that the N2O concentration is too high, or that the gas has been administered for too long. This stage can be associated with side effects such as nausea and other potentially unpleasant sensations, including flashbacks. N2O concentration should always be gradually increased (“titrated”) at each visit, because people’s tolerance can vary from day to day. If you’ve had bad experiences with this in the past, it is highly likely that these were due to improper administration and too high a concentration of N2O. According to XXXXXXX who’s a bit of an expert in the field, the normal working concentration of gases is about 70% oxygen to 30% nitrous oxide: “It’s rare to go beyond that because that’s what brings on the nausea. More than 45% N2O induces vomiting. The reason why titration should ideally be used at every single time is because of potential adverse effects in the event of oversedation (including flashbacks of traumatic past events, as well as physical ill-effects). However, other experts say that it’s ok to use a mix based on prior experience (a concentration which a particular patient has experienced as pleasant during previous appointments). Quite a lot of dentists do this because it’s quicker. When you go for next visit ask your dentist to give concentration which was pleasant. The problem with this approach is that tolerance can vary from visit to visit, depending on both psychological and physiological factors. What was experienced as pleasant varies from person to person and from day to day. And once a person has been over sedated, they may come to dislike nitrous oxide so much that they don’t want to try it again. if you feel like trying in the lab with different conc you can but my sincere advise is not to do this as you now came to know the pleasant conc three wks before when you took it. Ask your dentist for the next time to use the same conc as the recent one. Do mind strengthening exercises like meditation daily this would abolish your flashback. Thank you.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Girija Kumari (10 hours later)

Thanks for the answer. I should point out while I was awaiting an answer that I came across the very same website where you got your answer. Looks like a cut and paste. No offense meant whatsoever. Here is the website. http://www.dentalfearcentral.org/help/sedation-dentistry/laughing-gas/ Would this sound familiar? Unfortunately that site didn't have the answers I was looking for since I already know those effects. I'm trying to explain the lack of an effect. I already accounted for the possibility of tolerance over time. This probably explains why I can have a higher setting and not get the same results as someone with less exposure under nitrous. Funny you should mention meditation. I already do this on a regular basis. I have gotten so good at this over the years I can now achieve that knife edge balance between wakefulness and sleep. The point where your body goes into sleep paralysis but are still awake. And it is a knife edge balance because if you don't focus (while staying relaxed at the same time) at that point you either fall asleep or wake up. Quite a sensation really. Your mind perceives sound differently in this state. It's like ultra high-def stereo. Inspiration is at a high point in this state. And if I can maintain it long enough, let's just say some very interesting things can happen. Secrets I don't feel like sharing....sorry. You'll have to discover that yourself. But it is worth it. The concentration of nitrous is kind of the problem here. If they had it on it's maximum setting and nothing happened, using the recent settings mean nothing. I know what happens when they use nitrous and can feel the effects coming on and the different levels. I don't jump from nothing to euphoria in seconds. And I analyze the different stages and the waves that follow if the setting is too high. That's how I keep my mind focused on other things while the dentist does his work. And it is exceedingly difficult to focus my mind elsewhere when my head is vibrating from the dentist's drill. The price to be paid for avoiding dentists for over a quarter century. So I guess the question here is where to go to get the answer to why nothing happened. If this was not an equipment malfunction, which I am leaning towards now, where can I find the answer? I've yet to find the answers online. No offense by the way. My mind is analytical by nature. When it goes into an altered state I view it with curiosity. I'm thinking that on your end you may be thinking that I must've been hallucinating that there were no effects. And I understand this point. However, knowing the different stages you pass through going in and out of an altered state is a very good roadmap into whether or not it was real or imagined. It still takes time to get to the saturation point and I can measure those changes and weigh them accordingly. Hard to get to hallucination when you haven't even reached the relaxed stage. Harder still to believe there was a hallucination when you don't feel the changes that happen once the nitrous is cut off. Well, thanks anyway. Maybe there are some tech journals on the subject you can refer me to that will help. I've already had my doctor give me a slip for a physical. Maybe that will answer some questions. Was overdue for a physical anyway.Sorry, forgot to add this link. If you are into meditation, this link may be of use. When you hit that state between sleep and wakefulness this music really stands out. I bought it because listening to it online ruined the experience. I could hear the sound of the internet buzzing in the background and found it irritating. Never hear that when I'm just relaxing. https://www.youtube.com/watch?v=dOEvKulq2sY

Answered by Dr. Girija Kumari (18 hours later)

Brief Answer: I'll keep you updated after reading journals.. Detailed Answer: I am pleased to know you are well versed and educated about most aspects. The effects or rather the stages of responses that occur following inhalation anaesthetic drugs such as nitrous oxide is definitely dose dependent. Further the duration of each of these stages are also determined by the concentration of this drug. In my experience I see patients reporting about flashbacks when concentration of NO is 40 to 45. Very few experience flash backs when NO concentration is below 40. Therefore since you had no flash back experiences, I would only think that you received NO between 30 to 40 - just enough to give the analgesic effects. It would be extremely hard to predict if the machine was faulty. But if your dentist are very sure you received higher settings above 45, then I will read and search the journals again. In short, as per my experience you would have receive NO:02 ration between 30:70 and 40:60. Chances of flashbacks are lower with this setting. Regards

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Above answer was peer-reviewed by : Dr. Prasad