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Like all drugs, DXM has side effects and risks. While mild in most people, they cannot be ignored. DXM is not a "safe drug" or a "harmless drug" (two oxymorons if there ever were).
Although generally very safe, you should be aware of some of the possible adverse effects that can occur with occasional use of DXM. These are ordered roughly by frequency of reporting, but I don't have any hard figures yet.
Probably the most commonly reported side effect is nausea, most likely a simple result of gagging down a bottle or two of cough syrup. People who use the gelcap or capsule preparations do not, in general, experience nausea, although DXM itself can occasionally cause nausea (this is uncommon).
Many cough syrup preparations can cause considerable amounts of bloating and gas. Expect to pass gas for the next day. Stomach cramps and other gastric disturbances, probably from the amount of sugars and glycerine, are also common. Preparations with guaifenesin tend to induce vomiting at recreational DXM levels. Mixing DXM with large amounts of alcohol can have the same effect; one poor individual who mixed DXM with a large quantity of alcohol vomited for over two hours.
Ah, the "Robo Itch". Some people get it and some don't. There's evidence that at least some of the cases of "Robo Itch" are a psychological reaction to mild anesthesia, but some are probably a result of histamine release - not necessarily an allergic reaction per se, but a possible consequence of DXM's pharmacology. The itching tends to go away, and although scratching is pleasurable (and a loofah is wonderful), take care not to overdo it.
Actual allergic reactions have occurred, and often these are a result of the "inert" ingredients, usually one of the dyes (e.g., tartrazine). A topical antihistamine spray might be a good idea. You should probably always keep an oral antihistamine on-hand, at least during your first few DXM experiences (or when trying out new preparations). Just remember not to use any prescription, non-drowsy antihistamine with DXM. Diphenhydramine (Benadryl) is a good OTC antihistamine that is regarded as safe to combine with DXM.
Note that some people find the itching to be extremely unpleasant.
Yes, hangovers can happen. See Section 4.5.
Although it doesn't happen to everyone, many report substantial pupil dilation on DXM, similar to the pupil dilating effect of LSD. This is probably a dead giveaway that you're "on something", so you might want to know if it happens to you before trying to get away with being on DXM in public. And may your eyes dilate to the size of saucers and attract cops for miles around if you ever drive on DXM!
This seems to be fairly common but not particularly serious; generally, a heart rate in the range of 90 to 120 can occur. This is probably a side effect of the stimulant qualities of DXM. Substantially higher heart rate may indicate a panic attack.
Hot and cold flashes during the trip are to be expected, and are not generally serious. One user reported frequent extreme hot flashes, which eventually got bad enough that he sought medical assistance. A few people have reported hot flashes several days after the DXM trip is over.
One user reported a case of hyperthermia (increased body temperature) which could have been dangerous. See Section 4.8.
Several users have reported panic attacks, and I am beginning to think some people may be susceptible to this from DXM. This seems to be worse when the DXM is combined with other drugs, including marijuana (cannabis). The trouble with a panic attack is, once you realize you're having one, it can make you feel out of control of the drug experience, which makes the panic attack even worse. This is a difficult vicious circle for some people to break. Fortunately this mostly seems to happen with high doses (around 10mg/kg and up).
As DXM is a dissociative anesthetic, it will make you less aware of the normal body senses, including muscle fatigue and pain. As a result you can easily over-exert or over-stretch yourself, especially if you are out dancing or engaging in other physical activity. Pay close attention to your body if you plan on moving a lot.
On a somewhat related note, many people report that heavy exercise under the influence of DXM can cause nausea. This seems to occur mainly at the second plateau and above; in contrast, one user reported swimming on a first plateau dose to be a very pleasant experience.
Psychological side effects can be quite varied. Bad trips are certainly possible, as with any drug. As with other psychoactive drugs, especially hallucinogens, there is always the chance that a mental illness may be triggered by the experience. Keep in mind that DXM is related (although distantly) to PCP, and some people really don't get along well with dissociative anesthetics. The chance of experiencing a psychotic episode probably increases with dosage.
Many of the cases of DXM "abuse" in literature have concerned psychotic episodes (the same is true for LSD). This probably seems more disturbing than it really is; after all, these are cases compiled from hospital visits. The vast majority of DXM users do not experience psychotic episodes.
I have heard of this happening exactly once, when DXM was used in combination with pseudoephedrine. DXM itself may be capable of inducing hypertension, since it is a dopamine reuptake inhibitor; however, at doses high enough to do this, DXM's NMDA blocking activity seems to counteract this problem. In any case, be careful when mixing DXM with other stimulants (caffeine is probably OK), and don't use DXM if you have high blood pressure.
Even though DXM has been successfully used to prevent seizures, it may actually induce them at high dosage levels (45), especially in epileptics (145). You want to avoid this.
Some users who have taken very high dosages of DXM (above 15mg/kg) have lost motor function to the point of choking on their tongues (or at least feeling like it; I've been told that this is technically impossible). Obviously, nobody should be experimenting at this level without a (sober) assistant. If this happens, seek medical assistance. While I cannot vouch for the efficacy or safety of this procedure, I have been told that one can maintain the airway by grabbing the person's tongue and holding it out of his or her mouth until motor function is regained. Don't try to insert anything into the person's mouth; it could slip and make the problem worse.
One user with a blind spot in one eye due to a stroke reported hallucinations in the blind spot persisting for several days. This eventually went away but was not particularly enjoyable. LSD, cannabis, and alcohol all failed to induce this effect. Ketamine did, however.
Prolonged, regular use of DXM has some definite risks. The most common is mania; this has been reported in people who used large amounts of DXM (especially to self-medicate depression) (1-3, 133, 137, 142-144). This is probably a result of dopamine reuptake inhibition, but sigma receptors may be involved as well (see Section 6). On the other hand, one user who had formerly used the antidepressant bupropion (Wellbutrin) reported a similar but somewhat stronger antidepressant effect from DXM, though with greater adverse side effects.
Recently, an article in Journal of Psychiatry and Neuroscience presented a case of significant cognitive impairment associated with long-term DXM use. The individual consumed 1500mg DXM, plus 5000mg guaifenesin, at least once per week for at least a year. From the article it seems that he was probably a slow metabolizer, lacking the normal P450-2D6 enzyme. It also mentions that he abstained for "several weeks" without improvement, possibly indicating permanent brain damage. The authors hypothesize that this unfortunate individual may have had a temporal lobe seizure disorder (137).
The reports I have received from several long-term (1-2 years) high-dosage users do not show lasting cognitive impairment, and this case seems to be the exception rather than the rule. Personal susceptibility may have a lot to do with it. Still, please be careful about regular use.
DXM, like any other NMDA blocking agent (including alcohol), will impair short-term and possibly long-term memory. This should go away after the user has stopped taking DXM, although it may take some time for things to return to normal.
Addiction is certainly possible but not common; see Sections 4.3 and 4.4.
Again, possible but not common. See Sections 4.3 and 4.4.
Another possible effect of long-term DXM use is neurotoxicity, specifically toxicity to 5HT (serotonin) secreting neurons. This has not been observed, but would be consistent with DXM's hypothesized ability to induce 5HT and dopamine release (52). Such neurotoxicity would be similar to the neurotoxicity resulting from use of MDMA (ecstasy). On the other hand, MDMA's neurotoxicity in humans is itself doubtful.
Recently, animal studies have shown that PCP can cause damage to specific types of brain cells, probably as a result of neurotransmitter release triggered by NMDA blockade (101, 136). This effect is known as NMDA Receptor Hypofunction (NRH), and currently it is not known just how much of a problem it is. It is possible that NRH may be partly responsible for alcohol's neurotoxicity. However, nobody knows if NRH is relevant in humans, nor is it known whether DXM would induce the same effect as PCP.
Excitotoxic rebound is a process by which brain cells, accustomed to a lower level of activity, essentially "burn themselves out" when a depressant drug is removed. Alcohol, benzodiazepines (tranquilizers, e.g., Valium), and barbiturates (sedative-hypnotics or "downers") are well known for causing severe excitotoxic rebound. It is possible that regular use of DXM could lead to an upregulation (i.e., increase in number) of NMDA receptors as the body tries to compensate for the blocking effect of DXM. Sudden cessation of DXM could leave the brain cells with too many NMDA receptors, leading to excitotoxicity. This is certainly just speculation, and although probably nothing to worry about, it might be another good reason to avoid regular DXM use.
Some research has linked sigma receptors to schizophrenia (46-49), and chronic use of NMDA antagonists has been shown to upregulate (increase the number or activity of) dopamine receptors (50). This could theoretically mean that DXM could trigger schizophrenia in susceptible individuals, although nobody knows for sure. PCP has been known to trigger psychosis in susceptible individuals, and DXM may have the same capacity.
Along a similar line, people using dissociative anesthetics on a regular basis sometimes develop a temporary psychosis a bit like mild schizophrenia. Usually the users don't notice until people tell them they are beginning to act inappropriately or weird. DXM may cause this problem if used regularly. Some researchers have suggested that chronic NMDA blockade and/or sigma activity may be responsible for schizophrenia or Alzheimer's disease (101).
I have found no evidence of liver or kidney toxicity from DXM itself. This doesn't mean that there isn't any, just that I haven't found any references indicating this. DXM tends to be metabolized fairly well, and neither it nor its metabolites seem to be toxic to the body.
On the other hand, the large amounts of "inert" ingredients may be dangerous to the kidneys and/or pancreas, especially if taken on an empty stomach. At least one chronic (9 month) user became unable to take any type of cough syrup (containing DXM or not) without severe kidney pain and bloody urine. Gel-caps failed to induce this adverse effect. Another two former users have reported similar effects, so this may be something to worry about.
Although some authors have suggested the possibility of DXM-induced bromism (147), actual blood tests have revealed little danger to occasional users, even with large doses of DXM (137). Daily use might lead to a dangerous buildup. Notable symptoms of bromide poisoning include headache, irritation, slurred speech, psychosis, weight loss, hallucinations, and an acne-like rash.
DXM may decrease immune function due to sigma activity (51).
Chronic use of NMDA antagonists seems to modify alcohol tolerance; this is based mostly on anecdotal evidence and theory, but it appears to be a very real phenomenon. If true, then it is important to note that the GABA receptor effects of alcohol may NOT be changed; in practical terms, you might be a lot drunker than you feel, and this could possibly lead to alcohol poisoning. Be careful, and limit yourself to as little alcohol as possible when using DXM. A recent paper supports the ability of DXM to affect alcohol tolerance (53), although this paper was concerned with a different effect, i.e., prevention of learned tolerance by NMDA antagonists.
At least one user has reported that very long-term regular use of DXM (recreationally) can lead to a constant hacking dry cough. I have not been able either to confirm or to disprove this.
From one viewpoint, of course, anything can be addictive - television, chocolate, masturbation, self-mutilation, etc. So in that sense, yes, DXM can be addictive. Somewhat more relevant are the degree to which DXM is addictive, and how such addiction manifests itself. The quick answer is, DXM can be addictive if you use too much, too often.
The traditional distinction made with respect to addiction is between physical addiction and psychological addiction. As examples, alcohol is physically addictive, whereas marijuana is psychologically addictive. Unfortunately this distinction has its problems - not the least of which is that since the brain is a physical construct, any addiction is in some sense "physical."
As physical addiction is a somewhat nebulous concept at best, I prefer to use the concrete ideas of tolerance and serious withdrawal symptoms. Tolerance is a process by which the body and brain adjust to a drug so that the dosage must be increased to achieve the same effect (some drugs, such as nitrous oxide, exhibit reverse tolerance). "Serious" withdrawal symptoms is somewhat less clear, unfortunately. Note that it is possible to become tolerant to a drug without being psychologically addicted; in fact, some people lose the desire to use a drug when tolerance takes away its more interesting effects.
There is considerable evidence based on personal reports that tolerance to DXM's more interesting dissociative effects builds quickly. This is a result of upregulation or sensitization of NMDA receptors, as well as possible changes in other receptors and systems indirectly affected by DXM. Cross-tolerance exists between DXM, PCP and ketamine, naturally. Some people seem to be immune to tolerance to dissociatives including DXM (lucky them).
Usually it takes several doses before tolerance is noticeable, although a few people have noted tolerance after just one dose. Larger doses will lead to quicker tolerance. Once tolerance has built, it takes at least three weeks before receptors will reregulate to normal levels. To avoid this problem, it is probably best to dose only once a week at most. Also, some people believe that receptors which are upregulated (or downregulated) for long periods of time may tend to stay that way. The practical upshot is you should take a month off every now and then (a good idea with any drug, incidentally).
Interestingly, the first plateau music euphoria effect also seems to disappear with repeated use of DXM. It's also one of the last effects to come back. This may be due to downregulation of dopamine receptors rather than upregulation of NMDA receptors. The practical upshot is, don't do DXM all the time. Again, some people are luckily immune to this tolerance effect.
For information on withdrawal and withdrawal symptoms, see the next section.
Psychological addiction to DXM has been noted a few times, and can theoretically lead to physical addiction. Generally, though, dissociatives aren't considered particularly habit-forming, since they tend to have such "heavy" effects. Low-dose DXM might be an exception due to its moderate to strong stimulant effect; in practicality, it's probably too hard to consistently hit the first plateau.
There are exceptions, some of them notable. One case report (133) involved a 23-year old male who maintained an incredible daily dose of 30mg/kg to 40mg/kg DXM (plus a six-pack of beer)! Needless to say, after maintaining this dose long enough, he had become addicted, although the authors consider it a "psychological" addiction, with withdrawal symptoms such as dysphoria, depression, and anxiety.
Most people who use DXM have noticed little or no addiction, and only mild tolerance (don't let that scare you; remember that coffee produces both tolerance and withdrawal symptoms). A few unfortunate people have developed problems with DXM. Prolonged, heavy use of DXM seems to induce dysphoria, anxiety, and/or depression in some people; as the dosage is increased, the problem gets worse. Unfortunately, at this point, there may be withdrawal problems (see the next section). If this happens to you, seek medical assistance.
Withdrawal from occasional DXM use is almost certainly not dangerous, and in fact any "symptoms" felt are probably just "jonesing" - the same sort of withdrawal "symptoms" felt with marijuana, television, sex, etc. At this point it's a matter of willpower more than anything else.
Once tolerance has built, withdrawal has the potential to cause more serious problems. Mild tolerance to DXM is probably no more dangerous than mild tolerance to alcohol (tolerance at the level of "being able to hold your liquor"). Withdrawal may produce boredom and mild anxiety, but rarely anything more troubling than that.
Beyond the mild tolerance level, things get rapidly worse. There is evidence that significant NMDA upregulation can lead to excitotoxic rebound (101), and many of the symptoms of opiate withdrawal may occur via a similar mechanism (110, 134). The good news is, studies generally haven't found any significant evidence of brain damage from heroin withdrawal, so withdrawal from DXM probably wouldn't be much trouble. The bad news is, heroin withdrawal isn't particularly enjoyable.
Interestingly, one person who developed addiction and tolerance to DXM also compared the withdrawal symptoms to those of heroin (although DXM never produced any of the positive effects of opiates in this individual). These symptoms included watery eyes, stuffy nose, gooseflesh, muscle spasms, increased pain sensitivity, nausea, anxiety, and depression. Furthermore, the individual eventually began to develop some of these symptoms even while using DXM. This is definitely something to avoid.
If you happen to develop a significant degree of tolerance to DXM, it might be a good idea not to quit "cold turkey" (all at once). Build down slowly over a few weeks, and avoid all other drugs in the mean time. One person who had been using DXM twice daily reported no withdrawal symptoms after decreasing the dosage 10% per day, and stopping at 180mg. This should prevent any excitotoxic rebound.
Hangovers from DXM trips are not common at lower dosage ranges (first and second plateau). Instead, many people report feeling energetic and refreshed the next day, although it seems that getting enough sleep is important here.
At higher dosage levels (third and fourth plateau), hangovers are more frequent. Hangover effects reported consist of lethargy, sleepiness, amotivation, mild sensory dissociation, muscle rigidity, muscle tics (especially in the jaw and hands), dizziness, loss of balance, headache, photophobia, and sharply diminished sense of taste. Some people say that everything tastes like slightly salty tepid water, or like MSG (monosodium glutamate, the flavor enhancer). Note that you're very unlikely to get all, or even most, of these symptoms.
Some of the hangover effect from high dosage trips is almost certainly due to residual DXM or dextrorphan, especially in individuals who lack P450-2D6, or in whom it is inhibited (e.g., by fluoxetine). To my knowledge there doesn't seem to be any way to speed up the metabolism; the best I can suggest is to exercise, drink plenty of water, take a multivitamin every day (don't overdo it, one is plenty) and possibly a small iron supplement (which just might increase cytochrome turnover), get enough sleep, and eat right. Don't take too much iron; iron is very toxic.
Other hangover effects may be due to neurotransmitter depletion (due to induction of 5HT and dopamine release), temporary inactivation of NMDA receptors (I doubt it, but there's been speculation), or just plain lack of sleep. Again, treating your body well is probably the best you can do.
Preventing hangovers may be possible to some degree. Certainly, make sure you are in good physical condition to start with, and don't try to stay up too late during your trip. Drink plenty of fluids (it is possible to get dehydrated; this can slow down the kidneys), and don't mix DXM with anything that could further deplete neurotransmitters (e.g., amphetamines, MDMA, etc.). Try to avoid going to sleep while still tripping hard - it seems to reduce the quality of sleep. Eat something before you go to sleep; usually DXM kills the appetite.
Another possibility is the use of nootropics ("Smart Drugs") to help prevent and alleviate hangovers. A good place to start for information is alt.psychoactives; another good place is Dean and Morganthaler's text on the subject. A healthy dose of skepticism is probably a good idea here; some of it might be placebo effect. There's evidence for and against; check Medline if you're interested. Note that unless otherwise specified, everything I mention should be available at health-food or mail-order vitamin suppliers (this is USA; I don't know about other countries).
Several people have reported beneficial effects from cholinergics, specifically choline (the precursor to acetylcholine), and DMAE (also a precursor, and a choline oxidase inhibitor). In both cases the bitartrate salt seems to be the usual (there is a liquid DMAE para-aminobenzoic acid formulation that tastes nasty and evidently doesn't work). Note that some people with depression, primarily endogenous, react very poorly to cholinergics. Also note that they can make you really, really irritable if you're susceptible. Regular use of DMAE seems to be the most effective, although that's something that you have to build up for a couple of weeks (Dean and Morganthaler suggest around 800mg per day in divided doses; please consult alt.psychoactives for nootropic information).
One-time use of DMAE or choline immediately before, during, or after the trip has also been reported to work, (in that order of preference), although not as well. Recommendations given to me have been 800mg DMAE, or 1500mg choline; in either case with 350mg vitamin B-5 (pantothenic acid) which acts as the relevant cofactor here. Don't go much above that.
There is some preliminary evidence (still haven't found the reference) that supplementary tyrosine may actually be useful in the case of dopamine depletion. Normally, the rate-limiting enzyme in the process is nearly saturated, so boosting tyrosine doesn't work. It's hypothesized that more enzyme may be produced in response to dopamine depletion. Furthermore, sigma activity may enhance synthesis of dopamine (115), so taking supplemental tyrosine is even more likely to be a good idea.
Vasopressin might also be useful; it seems to have a fair amount of success in combating intoxicants, possibly by affecting long-term potentiation (how I don't know). It's prescription in the USA, and it does have side effects.
One final note - do not take tryptophan! Although this isn't established, it's possible that NMDA receptors may be upregulated after a DXM trip (especially in chronic users). Tryptophan, in addition to leading to 5HT, also leads (along a much more efficient pathway) to a substance called quinolinic acid, which is very toxic to neurons, and acts via NMDA receptors.
The LD50 of DXM is not well known. In searching medical literature, I found only two cases of death associated with DXM use, both in Sweden. In one case, a girl was found dead in a public bathroom with two bottles of 30mg DXM tablets (the number of tablets is believed to be 50/bottle, but may be 15 or 25). She had previously tried to commit suicide using a bottle of 50 tablets (this leads me to believe that she had, in fact, taken 100 tablets, for a total dose of 3000mg). The other case involved a 27 year old man, and few details were specified. In both cases, death was apparently due to inhibition of respiration. Plasma levels of DXM were 9.2 and 3.3 micrograms per gram (cases 1 and 2); plasma levels of dextrorphan were 2.9 and 1.5 micrograms per gram. Liver levels of DXM were about an order of magnitude higher. In both cases, the ratio of DXM to dextrorphan was about 3 (9).
On the other hand, a dosage of 42mg/kg/day has been used in children (33), which would be 2500 to 3000mg for a 60-70kg adult. There is also a very low incidence of death associated with DXM use. Since a 42mg/kg dose in an adult may be stronger than the equivalent dose in a child (I have no reason to believe this, but it is possible), caution is advisable in taking this as an indication of safety.
The highest daily dose of DXM I've come across is from a case study of a 23-year old male (133). His daily dose was 3 to 4 12oz bottles of Robitussin DM, for a total of 2160mg (31mg/kg) to 2880mg (41mg/kg). He was, of course, considerably addicted to DXM, and had built up this dose over a long period of time.
It is reasonable to expect, given the data, and the available data on the effects of high DXM doses, that DXM starts becoming toxic around 25 to 30 mg/kg (about 2000g for adult of 150lb). This corresponds to between 5 and 8 4oz bottles of 3mg/ml cough syrup, i.e., a fairly large amount, but still within the realm of hardcore experimenters. Keep this in mind before you consider large doses. IV naloxone is considered the antidote for DXM overdose (54).
No. Definitely not. Use of medicine, OTC or not, contrary to instructions may be a violation of local, state, and/or federal law. I hereby specifically tell you not to use any DXM-containing product (or any other product) in a manner inconsistent with its labeling.
Even if DXM were legal for recreational use, I still wouldn't recommend it for frequent use, nor for high-dosage use. Frequent use may bring about undesirable changes as mentioned above. High-dosage use carries with it all the risks of any hallucinogen, and can be distinctly unpleasant. Very little is known about sigma, PCP, or NMDA receptors. You dork with them at your own risk, and that risk may be considerable.
Sound like a CYA answer? It sure is. Right now, in the USA, there are many people with nothing better to do than support legal paternalism and legal moralism. For whatever reason, some people feel that they have the right to tell a legal adult what she or he can and cannot do that involves only her/his body. And as long as this goes on, I'm going to make sure I'm not thrown into prison so they can free murderers and rapists to make room for me. So, I'm telling you - don't break the law.
This section covers suggestions for undesirable, unexpected, and emergency situations. Always remember, though, if you feel there is an emergency, get to a hospital. While DXM-related deaths are very, very rare, they have occurred. Nobody wants to see any more happen. None of this is intended to be medical advice or replace the judgment of a physician, nor should it be taken as such. These are general guidelines only, compiled from reports of DXM users. Neither I nor anyone else take responsibility for any injury, death, or other misfortune, resulting from this advice. There, have I covered my ass well enough? Probably not. Just remember, please use common sense and be careful!
Some people get the itch, some don't. Unfortunately, I still haven't been able to correlate it with anything, so I still can't figure out whether it comes from the DXM itself, or from a dye or other additive. It very well may be a reaction to dissociative anesthesia.
In any case, from all reports the best thing seems to be to wait for it to go away, and try to think about something else. Scratching is OK, so long as you don't injure yourself in the process (remember, you many not be feeling pain as you normally would). A loofah can be quite enjoyable, actually, should you feel the urge to take a bath (which evidently can itself be enjoyable on DXM. Just be careful!) You can try a topical antihistamine spray, but I doubt it will do any good.
If the itch is accompanied by a rash, swelling, or other symptoms of an allergic reaction, you should definitely take an oral antihistamine (not a prescription one), and make sure there is someone with you. If the allergic reaction continues, or you feel you may be going into shock, get to a hospital. To my knowledge this type of allergic reaction has never occurred.
Many times this is more a problem of perception than anything else. Still, it does happen. As far as I have been able to determine, DXM itself can raise the heart rate somewhat, about as much as a mild to moderate stimulant (e.g. a few cups of coffee to a "coffee virgin"). Reports have indicated a range of 90 to 120 beats per minute as the relevant range.
Panic attacks also can occur on DXM, especially in naive users or users rushing in to higher doses. A panic attack can increase the heart rate significantly, sometimes as much as 200 beats per minute! Unfortunately, panic attacks can be hard to control; the best thing to do seems to be to try to relax, go somewhere you feel comfortable, and focus on your environment. A panic attack is a positive feedback situation; once you start having one, the symptoms themselves can feed the fear. Breaking this vicious cycle can be difficult. If you are predisposed to panic attacks you should probably avoid DXM in the first place.
Prolonged very fast heartbeat, or fast heartbeat accompanied by chest pain or tightness, should be taken seriously and may be cause for medical attention (note that a panic attack can also cause a feeling of chest tightness). If in doubt, go to the hospital. Note also that people with existing heart problems should avoid recreational DXM use. Incidentally, neither of the recorded deaths due to DXM overdose were attributed to heart attack (respiratory failure was considered the cause).
An irregular heartbeat, like a fast heartbeat, may be a problem of perception more than anything else. Remember that, especially at higher doses, there can be a "sensory echo" effect which may influence your measurements.
An occasional feeling that your heart "skipped a beat" is usually not cause for worry. Sometimes it is due to spasms of the esophagus, stomach, or bronchial tubes and has nothing to do with the heart; it's hard to distinguish sensations among internal organs. More frequent heart irregularity, or irregularity with chest pain, may require medical attention. Go to the hospital if in doubt.
Ah, the joys of ingesting large amounts of thickening agents. Nausea is to be expected, especially with cough syrups. It usually goes away. Do not take anti-nausea medication. Some antiemetics are anticholinergics and/or CNS depressants, neither one of which you want to mix with DXM (meclizine would probably be okay, although I don't advise it). The best response seems to be to tough it out, or switch to gel-caps. Incidentally, avoid taking DXM with greasy or heavy foods.
Vomiting occasionally occurs, usually for the same reason as nausea. Again, not much to worry about. If you do vomit, just make sure to drink lots of water to replace what you just lost. Both guaifenesin and large amounts of alcohol tend to contribute to the tendency to vomit.
Gas and diarrhea, especially after the trip, are also fairly common with syrups. Not much to do, unfortunately; just tough it out and drink water.
This is mostly advice for the designated sober person; obviously it won't do you much good if you're unconscious. Unconsciousness with DXM is to my knowledge extremely rare (I've heard of it happening once).
Generally if someone passes out, the first thing to do is make sure they don't fall and hit their head. Yes, DXM may protect brain cells somewhat from the effects of head trauma, but let's not try out that theory ourselves. Make sure the unconscious person is lying down with their feet elevated, and that someone (sober) is with them. If you feel there is any danger of vomiting, roll the person onto his or her side.
At this point, if the individual is breathing well, and seems OK (other than being unconscious), you can wait it out if you feel comfortable doing so. The unconscious person may be flying around in a mental dreamscape, oblivious to you and the rest of the world. If there is any indication of irregular breathing, slow or weak heartbeat, or other problems (e.g., his face is blue), get to a hospital immediately. You may wish to indicate that IV naloxone is considered antidotal for DXM (naloxone is also used for opiate overdose, incidentally). I suppose it would be possible to have a syringe of naloxone on hand (it's actually fairly safe, being an opiate antagonist; to my knowledge it's not possible to overdose on it). However, it's not exactly something you can get at your local drugstore, and in any case other measures may be necessary which would require hospitalization.
Remember, if there is any indication or suspicion of an overdose, get medical assistance immediately!
First, make sure you actually have a fever. DXM can mess with your sense of temperature. On the other hand, I have received one report of DXM-induced hyperthermia that could have been dangerous. A temperature at or above 102°F (39°C) is entering the danger zone. If this happens to you (or someone you are with), the best way to cool down is by taking a cool bath or shower (make sure it feels cool to a normal person!), and drinking cold water. Incidentally, speaking from personal experience (with the flu, not DXM), the "cool" water will feel damn cold.
In the case of a fever at or above 105°F (40.5°C) you've got a real emergency on your hands. Immediately contact a doctor or hospital, and try to reduce the body temperature as quickly as possible. Ice-water baths are acceptable providing there is someone (sober) there to make sure the person doesn't pass out and drown. Expect to hear a lot of screaming; this is a significantly unpleasant experience even without a fever.
Again this is usually a perceptional problem, and sometimes is related to panic attacks. There is also evidence that dissociative anesthetics in general cause a transient phase of shortness of breath, possibly because the body is beginning to "take over" breathing from conscious control. Take deep, even, and slow breaths; hyperventilating won't help, and can make you feel even worse. It should clear up by itself. In the case of hyperventilation, the "breathing into a paper bag" trick really does work, by increasing blood CO2 levels.
If you start feeling like you are choking on your tongue, make sure someone can assist you, or call a doctor if you believe you really are choking. There is actually very little danger of choking on your tongue; it's pretty much physically impossible. Nonetheless it can seem frightening.
If you are in the position of trying to assist someone in this situation, open the person's mouth, tilt their head back slightly, and grasp and hold their tongue out of the way of their airway until they feel better. Avoid putting anything in their mouth; this could easily fall and cause much worse choking.
If you are prone to nosebleeds this probably isn't a problem and may be due to nasal irritation. If possible, check your blood pressure. If the nosebleed is prolonged, your blood pressure is high, you notice any burst capillaries in your eyes, or you experience sharp pains in your head or lungs, go to the hospital. I'm not familiar with any cases of DXM-induced hypertension, although it might be possible, especially when mixed with stimulants or MAOIs.
Remember, DXM at high levels can be very dissociative. You're not dead, you just can't feel your body right now. This state can have a lot in common with certain lucid dream states. A feeling of "being dead" is common with third and fourth plateau DXM doses. The best thing seems to be to try to make contact with some part of your body (this can take a lot of effort), to reassure you that you're still there. Then, relax and enjoy your trip.
This is another reason why you should a sober person with you. If you are in any real danger, he or she should take care of you.
Note: see also the guidelines on shamanic journeying in Section 3.12.
Hangovers can occur from higher doses. Usually you can expect to feel very relaxed if not lethargic for the next day after a heavy trip. You may also might experience dizziness, muscle rigidity, loss of balance, slight double-vision, and a general feeling of being "not all there". Again, it goes away. Sleep seems to improve things a great deal. Make sure to drink a lot of liquids, get plenty of rest, take a multivitamin, and exercise. As DXM is metabolized differently in different people, some may experience hangovers (and trips) a lot longer than others. For more details, see Section 4.5.
Very rarely, someone will come out of a DXM trip and seem to be very dissociated from the real world, behaving a little like a robot. Whenever this has been reported to me, the person in question had always taken a high (third to fourth plateau) dose, and in most cases had tried to achieve an out-of-body state (draw your own conclusions). Make sure the person is relaxed, and try to engage him or her in a familiar activity. Familiar environmental cues should go a long way towards bringing him or her back to the "real world". Also keep in mind that the person may be slow to metabolize DXM and thus still be tripping.
If, after a couple of days, the person still hasn't returned to normal, it's time to get worried. Contact your nearest psychologist, priest, shaman, or other equivalent. Note that I don't think there's any biological reason for this to happen.