Every day has the potential to go horribly wrong for someone with an anxiety disorder, but that doesn't mean it's good to avoid life. I suppose psychedelics aren't such a good idea though if you have anxiety. In any case, an adequate dose of benzo would calm a bad trip, or even the knowledge that you have the power to do this should be comforting. Alcohol should do much the same as benzos. If you don't mind losing all effects, mirtazapine is considered the best trip-killer available.
You could take something like an opioid with it to ensure it's always going in a positive direction, or MDMA, chronic SSRI dosing (despite a minor reduction in effects) or possibly agomelatine (should remove a lot of anxiety from a trip). I dunno, there are literally millions of options when poly-drug-using to get the best possible combination of effects. I was gonna suggest ketamine, but a combo such as ketamine + acid would redefine the word 'intense'...
Oh yeah, we aren't supposed to talk about rec. drugs here. Oops.