Beware of mixing DXM and other drugs, legal or not. Any time you do, you risk an adverse reaction with your own physiology that cannot be predicted. Nonetheless, people have asked about it and here are the results from people who have combined DXM and other drugs. In addition to the sections below, you may wish to consult Section 14.4 to see what people have written about their experiences with DXM and other drugs.
Some users report that a small amount of alcohol (a beer or two) before the DXM can both enhance the trip and prevent some nausea. Alcohol following the DXM trip seems to be reduced in some, but not all, of its effects. Note that large doses of alcohol combined with DXM often cause prolonged vomiting (up to 2 hours!) Alcohol after the end of a high dosage DXM trip has been reported to temporarily bring back many of the dissociative effects (cannabis and nitrous oxide also do this). This seems possible up to five days after the DXM trip, depending on your metabolism and brain chemistry.
Barbiturates ("downers") include drugs like seconal and nembutal; benzodiazepines include drugs like diazepam (ValiumTM), LibriumTM, and other antianxiety drugs. Generally speaking most but not all prescribed sedatives, antianxiety drugs, and recreational "downers" fall into this category.
Some people have reported that combining DXM with a low dose of a benzodiazepine can prevent some of the more annoying side effects (mostly related to overstimulation, high blood pressure, and tachycardia). Clonazepam (Clonopin[tm]) in particular has been reported to have specific effects in combination with DXM, different from other benzodiazepines. These effects include enhanced CEV's (closed-eye visuals) and, of course, limiting or preventing sympathomimetic effects (high blood pressure and heart rate, sweating, etc.). I can't recommend this, and these drugs are of course prescription-only, but it doesn't seem to me that a low dose would be harmful. Just don't do it regularly.
I strongly suggest you avoid barbiturates, and be careful with benzodiazpeines; both barbiturates and benzodiazepines tend to be dangerous enough by themselves and are frequently fatal when combined with other depressants (such as alcohol).
This is probably asking for high blood pressure problems, strokes, brain hemorrhages, and the like. While a few people enjoy this combination, most find it unpleasantly speedy anyway. Most who've tried it reported that DXM will potentiate other stimulants. Since DXM inhibits dopamine reuptake, combining it with a dopamine releasing agent (amphetamine or methamphetamine) will naturally produce a combined, synergistic effect. I'd suggesting avoiding this at all costs.
Combining DXM, a psychostimulant, and a monoamine oxidase inhibitor is a sure way to make your blood pressure skyrocket and will probably kill you (if you're lucky) or leave you with severe brain damage (if you aren't lucky).
DXM and cannabis is a frequent combination, which most people seem to enjoy, at least at lower doses of DXM. High doses of DXM (third plateau and up) mixed with cannabis can be very, very dissociative and sometimes unpleasant. A few people have reported that cannabis with DXM makes them feel very stupid.
One user reported that 360mg DXM followed 3.5h later by "a bowl or two" produced a very profound, and unique, intoxication. Severe flanging of all sensory input was present, and there was an overall "vibration" feeling present in the muscles. With eyes closed, he could think fairly clearly, and solve simple and complex tasks much easier than on DXM or cannabis alone; however, with eyes open (or other sensory distraction) cognitive abilities deteriorated rapidly. Motor skills were possible only when performed automatically; any attempt to focus on them led to difficulties.
Several users have reported that cannabis and DXM generally "go well" together. Note that cannabis after the DXM trip is over seems to bring back some of the dissociative effects, much like alcohol and nitrous oxide.
DXM probably interacts with marijuana at a pharmacological level. Dissociatives decrease the analgesic response to THC (214) and downregulate THC receptors (218).
I've received a limited number (about 20) of reports of mixing DXM with 5HT hallucinogens, primarily LSD and mushrooms. While one person said this combination was "not recommended", most have had incredibly profound experiences. On the other hand, very few of these have said they would ever repeat the combination, as it was simply far too powerful and terrifying. One person told me that DXM helped him avoid unpleasant cognitive effects and "bad trips" he might otherwise get from LSD alone. Regular use of DXM may alter the effects of LSD due to overall increase in 5HT binding (252) and decreased 5HT2 receptor binding (212).
A good description of the DXM + LSD experience was provided by one person:
Anyways that day I had been up about 18 hours when I took the lsd. After doing some fingerpainting and noticing how the visuals were pretty good for only 1 hit and just having recently tripped I decided to give the dxm another whirl. So I took 300mg.
At first I felt slightly out of it a bit drunk. As I sat in the chair however I began to feel like I was sinking deep within myself. It became very hard to focus on anything so I closed my eyes. Whew-wee what a mistake. The visuals were *intense* blinding lights, zooming, it was unlike anything I had ever seen. I opened my eyes and when they couldnt focus I began to feel horribly sick. So I went and threw up it lasted about 30 seconds and after I threw up (instantly) I began to feel incredibly fucked up. I was very depersonalized. I felt like I was nothing more than a dot inside my head. Focus on anything was next to impossible and my eyes began to shift a lot. The vertigo was immense if I looked at any repeating pattern. Enigma was playing on the stereo and it sounded so full and deep it was hard to listen to. I layed down and closed my eyes and began another rushing trip. This one was much more intenst than the first so intense that my brain began to feel very overloaded. I suddeny had to throw up again becase of the *music*; it was just too much to handle. At this point I felt incredibly horrible. My head felt like it was pulsating, as did my whole body. It was as though I was showering the room with excess energy. The music was turned off and I gained some composure. This time after thorwing up (just water) I felt wonderful. I relaxed and layed down again and then it began. The most wonderous experience of my life. There just are no words to describe the nenxt 4 or 5 hours. I would close my eyes and the visuals were so lifelike. It was like a waking dream where I had full control. Soemtimes it was hard to tell if my eyes were close or open. When they were open I was having mass hallucinations. Walls with paintings that werent there etc... It was just incredible...to sum up the pros and cons.
Dont do lsd+dxm if your not VERY stable. The possibility of a bad trip is easily much higher than the possibilty of a good one. Dont do dxm+lsd if you've ever had a bad trip due to repressed memories. Dont do dxm+lsd if your afraid of seeing wierd shit when you puke (if you puke on dxm) this I see as being extremely tramatic for a number of people. Dont do dxm+lsd if your worried about it. You will at time prolly feel like you are dying/or dead (the upside is you feel so content you dont really care).
Do dxm+lsd if you can take it and want the trip of your life. Quite simply I have never seen anything else that even came close to comparing.
Will I do it again? I doubt it. I achieved what I was looking for in the whole trip thing; complete and total fooling of my mind.
One person says that small amounts of opiates tend to "mellow out" the DXM trip, and reduce the possibility for panic attacks or anxiety. Another user said opiates should only be taken after the peak of the DXM trip, because otherwise they would cancel each other out to some degree.
On the other hand, this may be a dangerous combination, and I'd recommend against it. Both DXM and opiates can depress respiration and high enough doses, and there might be a synergistic effect.
Recently, a new product has appeared on the streets containing heroin, scopolamine, dextromethorphan, cocaine, and thiamine. Called "Homicide" or "Super Buick", it presents extraordinary problems due to its high toxicity. Even worse, when naloxone is given for overdose, the toxicity of the other drugs can become apparent (371-372).
The few reports I have received have indicated that ketamine plus DXM was not much different from ketamine. One person said that a small dose of ketamine can boost the DXM experience by one plateau. I expect that most of DXM's particular effects on sigma receptors are overshadowed by ketamine's NMDA antagonism. Ketamine is a much more potent NMDA antagonist than DXM, and since they both compete for the same site, DXM isn't going to affect this much.
This is a combination I hadn't considered before, but which evidently is fairly interesting. Nicotine seems to vastly potentiate DXM's effects for some people, enough so that one user reported that one cigarette could floor him on a second plateau trip. Another user reported that nicotine helped him overcome some of the memory problems with higher doses of DXM, but tended to induce nausea.
On the other hand, several people have told me that DXM should be avoided if one smokes cigarettes regularly (even if you don't smoke during the trip), because of nausea, hot flashes, and other unpleasant interactions. This might be due to inhibition of MAO by cigarettes (378,379) and if so, cigarettes should be avoided.
I have very limited data on mixing these drugs with DXM. One person mixed DXM and 2CB ("bees") and had a wonderful experience:
Ever since I first read D.M. Turner's excellent Essential Psychedelic Guide and saw his glowing reports on the combination of Ketamine and bees, I have had quite a hankering to try an entheogenic cocktail of that variety. Bees have been plentiful lately, but Ketamine is as hard as ever to come by for me. Recently I had an interesting idea - since DXM is relatively close chemically and experientially to K, as well as being cheap, legal, and easy to acquire, why not use it as a substitute in the combo?
So the other night I took 300 mgs. of DXM in the form of Drixoral Cough Liquid Caps, a preparation that contains no other unwanted active ingredients like acetaminophen, guafinesen, or pseudoephedrine and has the added advantge of being low on sugars and syrups that can cause gatsric distress in large doses. This dose of DXM alone would not be sufficient to evoke a fully dissociative episode for me, but I decided to err on the side of caution as I usually do when trying a new mix. After an hour or so, I began to feel the euphoria that is my first alert with this particular material and took 20 mgs of bees. I was chatting on IRC at the time and within twenty minutes typing became much too complicated to deal with, so I lay down and relaxed into the trip.
There were some uncomfortable somatic symptoms at first, such as a feeling of physical heaviness similar to that induced by alcohol, minor stomach upset, and hot flashes (which had me a little worried until I took my temperature and found it to be normal.) Fortunately, these passed quickly as my consciousness dissociated from my body. I began to feel as if my soul was a soaring kite that was connected to my physical form by only the thinnest etheral guide rope. Then my physical awareness seemingly vanished, and I found myself in a state that was nearly identical to the experience of Ketamine that I had on the two occasions I was lucky enough to acquire some. I felt that I reverted back to the ground of being, the original undifferentiated oneness, the primal monad. Everything was perfect, all was one, and it was me. Then something fantastic happened. I felt as though I was given an opportunity to experience the original creation process that produced the material universe. I saw/felt/percieved the monad make love to itself and give birth to what we know as the manifest cosmos. I was the monad making love and giving birth, and it felt incredible, like multiple orgasms of universal proportions. This was a very meaningful episode for me, because it seemed to afford a pointed insight into one of the main philosophical questions I've been thinking about for quite some time. The question was: why did the monad split in the first place? Why disturb that original pristine oneness at all? As I shivered and shook with the pleasure of the birthing process, the answer seemed very clear: simply for the joy of the doing, not because of any kind of expected result. The universe is a work in progress, not a finished product, and it is the process of creation that is most important.
That episode lasted maybe half an hour or so, and then I began to gradually regain my physical consciousness. I spent the rest of the trip in a lovely state that I can only describe in terms of post-coital glow on a cosmic scale accompanied by the lovely visuals that are characteristic of the bees. Near the end of the experience, I had the opportunity to smoke some salvia, and had the feeling of communing with the spirit of the plant. It felt great; very warm and comforting. Ska Maria definitely likes the bees, and she seems to like me too! I slept about four hours and awoke the next morning feeling reborn and refreshed, enjoying a quite delightful afterglow that lasted the entire day. I reccomend the combination of bees and dissociatives highly, and will most definitely be doing further exploration along these lines in the future when the opportunity presents itself.
A few regular users of dimethylaminoethanol (DMAE), around 800mg per day, have reported that the regular use of DMAE prevents a lot of the memory and cognitive problems associated with DXM use, while still leaving the rest of its interesting effects. One user also reported that lecithin prevented some of the confusion associated with DXM.
A similar effect has been reported for piracetam. See also information on use of nootropics to limit hangover in Section 6.1.7.
Several people have reported to me that nitrous oxide goes well with DXM, especially towards the end of the trip. This seems to be consistent with nitrous oxide's effects in combination with other hallucinogens. Specifically, nitrous oxide seems to intensely multiply the flanging, "stoning", and dissociative effects without added adverse side effects.
Do not under any circumstances use DXM with yohimbine or any other alpha-2 adrenergic antagonist. This combination could vastly potentiate the danger of Olney's lesions (see Section 6.3.1).
It might be a good idea to avoid tetrodotoxin, given DXM's sodium channel blocking ability. (This is a joke! No, don't go out and try zombie potion).