please use the search function next time! there has been many threads in PD, BDD, and OD about DXM daily usage.
i have used DXM Daily in low doses for an extended period of time 3-4months at a time to act as an anti-depressant, and besides wellbutrin, is the only SSRI or atypical AD that helps depression and brightens my mood. at low doses (60-200mgs ), DXM mainly functions as a SNRI (stronger SERT affinity then NET), sigma-1 receptor agonist, nACH receptor antagonist, and a weak NMDA antagonist. i usually stuck around 60-120mg DXM XR daily, or 60mgs twice a day. low and behold, DXM at low doses (no higher than 200mg a day) helped with depression and anxiety extremely well. i recommend more around the 90-150mg dose for depression/anxiety. however, you have to find a product that ONLY contains DXM or DXM polistirex (XR). finally, the syrups are packed with dextrose and food coloring that will fuck with your GI tract if you take too much for too long. try to find a powdered DXM, buy a capsule and scale. my body really really likes DXM and responds well to DXM in low and medium doses (200-300) but i dont like above 350+mgs, id rather do MXE. howver, with every action has an equal reaction, and so i experienced some side-effects, but they were slim and not that intense: stimulation, ED/unable to orgasm, anorexia, pruritus (desire to itch due to histamine rxn), slight memory impairment, nausea, drowsiness, dizziness, CEVs, ect... could occur. the main side effects i encountered were stimulation, pruritus, unable to pee, ED/orgasm troubles, anorexia, and drowsiness. DXM, being a pro-drug, produces a wide variety of results when ingested based on the DXM to DXO ratio. some people are 2d6 deficiency and end up with higher DXM concentration than DXO, some people are fast metabolizers and might like DXM better because they can produce more DXO and get ore euphoria, skinny people usually have faster metabolisms than fat people so they might like DXM more...as you can see results vary, and the line between i feel good as fuck, and holy shit get me out of this place is highly volatile. one day 200mg will have me tripping my ass off, the next week 300mgs might just give a slight buzz, ect...
the erowid page says that contrary to popular belief and with other drugs, more DXO is converted is one big DXM is taken all at once rather than split up into smaller doses over a period of time. i dont believe this to be true, because with other pro-drugs, or drugs with potent metabolites (i.e. tramadol or codeine) i get a better affect from stacking my doses, especially with tramadol. tramadol acts very similarly to DXM, they both have similar pharmacology such as affecting the same neurotransmitters (serotonin, norepinephrine), binding to similar receptors sites (both are NMDA antagonists and slight opiate agonists - DXM/DXO blocking NMDAr stronger and more effective than ulram, while tramadol/Odesmethyltramadol agonize opiates receptors with a higher affinity or lower Ki value), and both dextromethorphan and ultram are pro-drugs meaning that both are metabolized in the body to their parent drug which accounts for the "effects" of dxm and tram (DXM --> DXO; tramadol --> Odesmethyltramadol). in addition, both ultram and dex are metabolized into their parent drug through 2D6, so i dont know why dosing for DXM would be different from tramadol in the aspect of maximizing the amount of pro-drug accumulated and accounted for.
personally, i like Delsym (DXM polistirex = extended release DXM) for depression/anxiety daily use, and i like IR DXM syrups for getting fucked up, but DXM XR works well for getting fucked up, just the length is increased to 12hrs. i have heard mixed accounts from fellow bluelighters, other drug forums, and erowid about optimizing DXO production. some say that it DXM XR or stacking DXM IR doses throughout the day produces the most DXO, while some say that one big instant release dose will produce the most DXO. idk what to believe, but i am leaning towards that DXM XR or splitting up the DXM IR dose throughout the day produces the most DXO. i draw my conclusion that XR is better for DXO production because DXM XR seems much "cleaner," less speedy than DXM, and more CEV's all of which hints that there is higher DXO levels in my body than DXM, which is what you want.
alright im rambling. use the search function or google, this has been discussed over and over and over again... tl;dr version: 60-200mgs a daily is no more dangerous than taking effexor or cymbalta for an extended period of time. i would make sure to take a break even now and then after each cycle. like take dxm low doses for 3 weeks, lay off for 1-2 weeks, rinse repeat. however. taking 350+mgs a day will have the same risks associated with taking other NMDA antagonists daily like MXE or Ketamine