typical dose: 20-150 mg ketamine (intranasally), 150-800 mg dextromethorphan hbr ketamine and dextromethorphan are dissociatives. dissociatives act by blocking sensory input, including the feeling of pain. for this reason, they are often called dissociative anaesthetics, and some dissociatives like ketamine have found medical use in surgery. dissociatives primarily act as antagonists on the nmda (n-methyl-d-aspartate) system in the brain. ketamine is widely used as a veterinary anaesthetic and as a surgical anaesthetic for children, who do not experience its trip-like effects. ketamine obtained for recreational use may already be in powder form or it may be in water in a vial from a pharmaceutical manufacturer for direct injection. usually, the liquid in the vial is evaporated to yield powder. the powder is then insufflated (snorted), but it may also be ingested. snorted ketamine comes on fairly quickly, lasts perhaps thirty minutes, then drops off rapidly. effects include fragmenting of the visual field, distortions of geometry and perspective, narrowing and quieting of audio, prominent skin numbness, and disconnection from reality. basically, it becomes difficult to understand and process what is going on. there is a distinct feeling that you have entered another reality - this is the reality inside your head, as all your senses are slowly turned off. you may feel like you're never going to come back. don't worry, just remember that you will. the "k-hole" is the point of complete dissociation. it's when you have lost contact wik your senses and are existing only as a mind unconnected to anything physical. you may have genuine hallucinations. some people report contact wik alien or transdimensional entities. the feeling that you have permanently fried your brain is a common one (but you haven't). as you can probably guess by this point, dissociatives are serious drugs that should not be taken lightly. make sure you know what you're getting into if you choose to take them. another recreational dissociative is dextromethorphan. dextromethorphan is also the active antitussive ingredient in many over-the-counter cough medicines. yes, this means that you can get high off cough syrup. if you choose to do this, you absolutely must purchase an otc product that contains only dextromethorphan hydrobromide as the active ingredient, since you're going to take way more than the manufacturer intended. if it contains acetaminophen, you might nuke your liver and die. if it contains chlorpheniramine, you might have a massive anticholinergic response and die. if it contains guaifenesin, you probably won't die, but you'll create an intimate new relationship between your stomach and the toilet. basically, drinking cough syrup is a pretty bad idea. but if you're going to do it, and you've chosen a brand like robitussin maximum strength cough or the generic tussin maximum strength, you now need to choose your dosage. these brands typically have 3 mg/ml of dextromethorphan hbr, so a 4 oz bottle is about 350 mg and an 8 oz bottle is 700 mg. 350 mg is a good trip. starting at about 200 mg is a much better idea. 700 mg will probably fully dissociate you from reality, and if you don't know what to expect, it will probably scare the crap out of you. some common effects include a "flanging" of sounds, stroboscope-like visuals (as if the refresh rate of your eyes was reduced), a disconnection between thought and action (e.g., you think to speak, and you hear yourself speaking, wikout ever consciously executing the act of speech), and real hallucinations. many people say that it defies explanation. because dextromethorphan is such a strange and potentially dangerous drug, there is a lot you need to know about it before you use it - way more than we could fit in this pamphlet. go to the incredible dxm faq at http://www.frognet.net/dxm/ and read just about everything. dissociatives cause brain damage. this is no longer a debatable point. nmda-blockading drugs (so the theory goes) cause overstimulation of certain neurons, causing them to burn too much energy too rapidly. intracellular organelles begin to malfunction - mitochondria may rupture, and the proliferation of free radicals starts to rip apart the cell from the inside. the cell detects this and produces hsp70, a heat shock protein, which shuts the cell down in anticipation of future repairs. but if the overstimulation continues, the cell can literally "burn out" and die. thus, excessive use of dissociatives really can fry your brain.