Coingestion of alcohol (ethanol) also increases the blood plasma levels of d-methylphenidate by up to 40% -- according to wikipedia, resource was cited too
It also combines to form ethylphenidate, but it only produces the mostly inactive isomer. I tried drinking alcohol to aid the comedown of my first ritalin experience, just made it stronger and last longer. I've since used alcohol to strengthen the effects during the experience.
Like Venrak said, nourish yourself. Eat some food, drink some water, take care of yourself. Comedowns from stims can be less harsh when you maintain nourishment during the experience and don't deprive yourself. Vitamins too, specifically b-complex. On my recent ritalin binge I neglected to take any vitamins to counter the depletion. Ended up with a b-vitamin deficiency and a vein in my arm broke as a result. Or, atleast I read that veins can break open like mine did with a b-vitamin deficiency so I presumed that was the case. Nothing serious though, just bruising around the vein for a few days and it took care of it's self and healed after a few more days.
Someone said weed can increase anxiety from the comedown. That can be true, but I never experienced any anxiety from stims or cannabis. I was able to smoke some during a comedown and get some benefit from it. Go ahead and try it if you're not prone to anxiety from either of them. Kratom was usually enough to counter the comedown for me. Opiates/opiods or benzos are common choices for stim comedowns.