Originally Posted by masterofpuppets
Drugs can be harmful or harmless. Most drugs when used correctly have no toxicity. However APAP, like many other substances, is potentially toxic, particularily to those with a weakened liver. The fact that they are not natural to the body makes no difference. Oxygen is not endogenous, yet it's perfectly harmless and we need it to live. Unless of course by not natural to the body, you mean, unwanted by the body. A better example would be alcohol. It's by no means natural to the body (other than small amounts formed in the gut which certain bacteria use to respirate), it has many health problems related to it, however most of these problems are caused by consuming unsafe amounts of alcohol. The liver produces enough Ethanol Dehydrogenase to cope with small to moderate amounts of alcohol, however excess levels of alcohol I believe are metabolized into fat which builds up in the liver, causing fibrosis, cirrhosis, and such. Somebody correct me if I'm wrong there. Let alone the neurological damage large amounts of alcohol can cause. HOWEVER in smaller amounts it is pretty harmless (unless of course your liver isn't functioning correctly). An example of a toxic, but potentially beneficial drug are chemotherapeutic agents such as nitrogen mustards (alkylating agents), methotrexate (anti-metabolites, which are sometimes used to delay worsening of several auto-immune dieases such as rheumatoid arthritis), and several plant alkaloids including vincristine and paclitaxel (vinca alkaloids and taxanes respectively). Their desired action is purely toxic, hence why they have so many side-effects. However the majority of drugs are harmless, have little to no toxicity in therapeutic doses and little to no side-effects. I am not denying that some drugs aren't toxic, but the majority of them really aren't unless used incorrectly.
