I know this is old thread but I found it when searching dxm&tramadol. I have also took in the past too much DXM (600mg) and forgot it's metabolite long half-life and took the next day tramadol something like 150-300mg and got quite nasty serotonin/noradrenalin syndrome few hours after that.
Today many - many years later and somewhat wiser after that incident - I took 40mg DXM and 100mg tramadol about 1h after that. I am trying to lower my tolerance to tramadol with DXM and Naltrexone simultaneously it seems to be working (especially naltrexone). But this is the first time I took this much DXM with that high dose of tramadol so I am too a little concerned (because of my previous nasty experiences) about getting too much serotonin. But I suppose this dose should be safe that is why I took it before I came here to search for more as I have allready searched for info many years before. I can report my feelings after 2-3h.. that is when it last time hit hard when I had took much more DXM the day before.
But I don't understand why some people here say DXM is shit or maybe even seems to be some consensus here that it is worthless. I mean there are tons of studies regarding DXM as neuroprotective in multiple different scenarios and with many different mechanisms ex. Anti-inflammatory, antioxidant, preventing glutamate excitotoxicity and abolishing those inflammatory cascades from too much calcium influx, preventing toxicity of neuroleptics and protecting even dopaminergic neurons and helping even with atherosclehoris because of it's anti-inflammatory effects. It has even been noted that those who have used the most cough medicine in their lives are less likely to develop dementia/alzheimer. That is why they are trying to develop some form of drug from it. Allready they have developed that antidepressant called Auvelity (
www.auvelity.com). It has sigma agonism besides moderate NMDA-antagonism and also acts as a very good antidepressant for many besides increasing neurotransmitters and decreasing inflammation&toxicity by activating anabolic mTor pathways and BDNF signalling so it is also anabolic/anticatabolic to brains. I have extensive history of usage with DXM and it can even (or propably) cause mania with high doses and really can have this quite distinct nootropic effects ex. Enchancing memory and cognition (I have wrote about those experiences at 2012 when I was in quite egomaniac state after using it many years daily with doses like 600mg/d or more. I speculate it really can spur new synapse growth by creating this anabolic/anticatabolic enviroment. But it will cause or can cause severe mania if used with high doses for long periods of time and then it will eventually make you feel dumb and depressed. Especially after you stop it. So I think there is some dosage range where it is mostly neuroprotective and beneficial for the brains but when the dose is increased past that point it can become the opposite - at least in the long term from psycholocigal standpoint not necessarily physically toxic per se. It will inflate the ego massively.
I don't also understand why many hear say tramadol is shit. Ok, I understand for some or even many it is not suitable but for me it has been maybe the best opioid I have used. As it is simultaneously calming but keeps you alert as it is "dirty" and has this serotonergic/noradrenergic component in it. So for me it has been very good medication. I have now again used it few months with good results.
Also I have extensive history with gabapentinoids like pregabalin, phenibut and gabapentin but for now I have used only gabapentin few months 2100-3000mg/d and some phenibut lately (only week). I have been in the past addicted to >1200mg pregabalin and >10g phenibut per day in the past and I know those withdrawals. I also eat clonazepam but I am withdrawing from that now.. Now I am focusing lowering tolerance to opioids ie. Tramadol. But I am not planning to withdraw from gabapentin or tramadol yet. They have been working quite well for me.
Edit: For the DXM, I will add that I even consider it so good neuroprotective that I would use it (and have it in stock) if I got ex. Some hit, trauma or oxygen deprivation in the head. Stroke or something. I would use it with progesterone, methylene blue and vitamin C (high dose -5-10g, I allready use daily 5g) and some other vitamins/herbals like vitamin E (tocotrienols+tocopherols) bacopa, gotu kola and citicoline. And some gabaergics too.
