Not the poster you replied to, but you should be careful about what you take with DXM. If you're taking it as a syrup, try and get a mixture with DXM as the only active ingredient. Some come with other additives which will make you sick, or stuff like paracetamol which will mess up your liver at high doses. I'm not sure if there are other bad interactions if you're already taking medication. And you might not find DXM enjoyable if you have a weak stomach, a lot of people find the nausea too much.
I've also heard that DXM tolerance never really goes away (but maybe this is just a psychological thing), so be wary of your dosage. A rule you might like to follow is the 1-week per plateau rule. That is, take a week's break for each plateau you hit. So if you hit second plateau, wait at least two weeks before your next dose, three weeks if you hit third and so on. This is not just for the sake of tolerance, but also just for protecting your mental stability more generally, since DXM is very intense. It's also good to have someone you can trust with you when you dose for the same reason.
I personally enjoy DXM with weed, but I've heard some people say mixing is a bad idea. In general, just be cautious and check erowid.