why do we develop torerance to drugs?

Answer 1

Liver cells contain structures called smooth endoplasmic reticulum. The membranes of the smooth ER contain enzymes that catalyze a series of reactions to detoxify both lipid-soluble drugs and harmful products of metabolism. Large quantities of certain compounds such as phenobarbital cause an increase in the amount of the smooth ER. The more of the drug you take the liver cells produce more Smooth ER to detoxify it. So the more of the drug is needed to give you the same level of what ever it does.

Answer 2

It depends what type of tolerance and what type of drugs you speak of. In some cases, the cells that are targeted by the cell will down-regulate the number of receptors for the drug in question. Thus, you need more drug to get the same effect out of that same cell that now has fewer receptors. Other drugs, when in the system in high enough concentrations, will hyperactivate your liver and you will catabolize ("burn up") more of the drug into an inactive form...so you'll need more drug. This hyperactivity of the liver can apply to other drugs that are in the system at the same time as the primary drug so you may need more of both. Often, a combination of both mechanisms are responsible for overall tolerance.

Answer 3

The body compensates for the effect. e.g. if the drug were to block the effect of a hormone the body would produce more of that hormone to compensate.

This is also why when you stop a drug suddenly you get withdrawal symptoms which are the opposite to the effects of being on the drug, your body has got used to over-compensating.

Answer 4

Because we have special cells in our body that adapt to them. It's the same reason we never catch the same cold...the cells remember how to fight it and it doesn't even affect us. Drugs are given in such a portion that they would still have an effect on us for a while, but eventually needed to be increased in dose.

Answer 5

Drugs (alcohol, nicotine, caffeine, cocaine, etc.) are poisons that happen to have psychoactive side-effects. Our bodies react to poisons by either dying, or breaking down the poison into safe substances. We get more efficient at neutralizing most poisons with repeated exposures.

However, there are some poisons (such as heavy metals) whose effects are cumulative, and cannot be eliminated from the body. We don't develop tolerance to these, because we can't break them down into safe compounds.

Answer 6

It's just how our bodies are. It works the same way as when you are exposed germs and bacteria (immunizations) and then you don't get sick. When your body is exposed to something it automatically begins to throw up defenses and counteract the alien substance. Over time you build up a defense or tolerance because your body knows how to counteract whats not supposed to be there and gets a little better at it each time. Hope this made sense. lol.

Answer 7

So we can take more