Why do doctors tell you not to chew or crush extended release pills?

Because they dissolve slower in your stomach and release slowly that way. Remember anything in your stomach isn't there for long so the release in your stomach is enough to keep an even level in your blood throughout the day. Take something like a coated extended Wellbutrin. It's designed to reach its half life in your blood stream about four hours after you take it. If you crush it it dumps the entire load and you could have a seizure. Before extended release you would take three-- one at morning, noon and night to keep the blood level consistent. Extended is so much easier. If you screw with meds--get a PDR. Like, if you suck the coating off a demerol and crush it and snort it? Well, your lungs are gonna fail in a couple of years. Every chemical compound is active atoms held together with crap. Every pill has crap meant to go through your liver and out. Your lungs? Stupid. Stupid. My brother-in-law the doc says that there's been a quadruple of bronchitis and pulmonary problems in under 25. Cause of the litter in their lungs. No one lasts past 25. If you want to do opiates don't snort a crushed pill. Remember mouth to stomach to liver and out. Vein to blood and brain and out. Nose to lungs and some to heart and rest in lungs. LSD? To brain and never comes out--the molecules are to big for the blood brain barrier to filter them out through the menges but since LSD is just molded rye it's bad but whatever. You swallow and it's stomach, glycogen, brain and never out again. Ecstasy destroys your dopamine receptors not the first time but eventually--you develop a condition called adanome--you will never feel anything again. Pot--if it's chronic with the off the chart THC? Your receptor cells will develop sites just for THC and if there is none your cells will whither and there will be no more ionic charge at those sites. You have millions, but remember that you're killing them. Depends how long you want to live without being able to wipe your butt. Nothing in life is free or without a consequence. Do want you want but accept that you are going to need those lungs, brain cells, liver when you get older and that you are the first generation to have access to this. And I'm just a scientist saying you should know that. People freak about herpes but snort a pill--stupid. Herpes is you either get it or you don't it depends on how strong a case of chicken pox you had. All the same virus--cold sore, herpes, chicken pox and shingles. Not a big deal. Take an anti-viral and you're fine. And most people can be exposed forever and never get it. Worry about real things--STD's that have no symptom what ever but destroy your fallopian tubes--no babies. Every time a woman goes to the gyno you need to say I had unprotected sex. They don't check you for anything unless you say that. Just the HPV--that's it.

Because it will not reach ur stomach and metabolize well and it is very bitter to swallow

Because your intenstines will absorb the medicine in time according to the coating of the pill against average absorbtion rates of people. Chewing means all the medicine will be absorbed quicker instead of little by little.

Because when you crush them you get too much medication at once....Instead of letting the pill dissolve into your system.

It is manufactured and formed in a particular way that your body will dissolve it or absorb it at a particular rate, extending it's effect over a greater length of time. FDA has approved it's use based on this and the prescribing physician is issuing the medication in this form for a good reason.

Altering it's form or ingestion method changes the drugs effect, and FDA has not approved it's use in this manner.

Ultimately: possibility for overdose, metabolize too quickly rendering it ineffective for the purpose prescribed or cause of adverse side effects.