How exactly?

[MORELLO]

Does alchohol impair the effectiveness of antibiotics, as suggested? If so, how exactly? Also,(strictly hypothetically) what would happen if local anaesthetic was ingested rather than injected into the tissues around the nerve as it should be? 

[j2buttonsw]

For the second bit, I read here 

http://www.nda.ox.ac.uk/wfsa/html/u04/u04_014.htm

"In clinical practice, local anaesthesia may be influenced by the local availability of free base (B), as only the unionised portion can diffuse through the neuronal membrane. Thus, local anaesthetics are relatively inactive when injected into tissues with an acid pH (e.g. pyogenic abscess) which is presumably due to reduced release of free base."

Since the stomach is extremely acidic I guess it would not work too good (although I expect your mouth and oesophagus would go numb)

[k8tkoo]

Got this from www.netdoctor .co.uk, have a read!

A drug has to travel through the bloodstream to the site in the body where it is to have its desired effect. The drug's effects then diminish over time, as it is processed [metabolised] and eliminated from the body. Alcohol behaves in a similar fashion, travelling through the bloodstream, before being metabolised and eliminated, primarily by the liver.

The extent to which each dose of any drug reaches its site of action may be termed its availability. Alcohol can influence the effectiveness of a drug by altering its availability. A single drink of alcohol or several drinks over some hours may prevent a drug's metabolism by competing with the drug for the same processing sites within the liver. This type of interaction prolongs the drug's availability, and may increase the risk of side effects from the drug. On the other hand, chronic alcohol abuse may cause an increase in the liver's ability to process the drug, thus decreasing availability and reducing its effects. This effect may persist for several weeks after stopping drinking. To complicate matters further, a drug may affect the way in which alcohol is broken down, increasing the risk of becoming intoxicated.The effects of certain antibiotics will be reduced when taken in combination with alcohol and as a rule, one should avoid combining alcohol with any medication.

[MORELLO]

Two very informative answers. Thanks to j2buttonsw & k8tkoo.  MORELLO