Alcohol , consider Aspirin

Since most codeine is dispensed as part of a compound preparation, potential side effects of the other drug(s) must also be considered. For instance, someone with stomach ulcers should not take codeine that is combined with a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen. Another type of risk from a compound preparation relates to codeine abuse. For instance, a person who abuses codeine might routinely take a dose of 100-200 mg of codeine to produce noticeable euphoria. Using Tylenol 3 to obtain this dose would also mean ingesting 1,000-2,000 mg of acetaminophen. Taking that amount of acetaminophen for any extended period presents a risk for liver damage, especially in combination with alcohol. 

A relatively nonpolar molecule, acetylsalicylic acid has the ability to penetrate membrane barriers that are also made up of nonpolar molecules. However, inside the membrane are many small water pockets, and when an acetylsalicylic acid molecule enters such a pocket, it ionizes into and acetylsalicylate ions. These ionic species become trapped in the interior regions of the membrane. The continued buildup of ions in this fashion weakens the structure of the membrane and eventually causes bleeding. Approximately 2 ml of blood are usually lost for every aspirin tablet taken, an amount not generally considered harmful. However, the action of aspirin can result in severe bleeding in some individuals. It is interesting to note that the presence of alcohol makes acetylsalicylic acid even more soluble in the membrane, and so further promotes the bleeding. 

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