Welcome to Just Answer and thanks for your question. One Librium per day should not make anyone fall down, slur words, or otherwise appear drunk. Librium and other drugs of that class do have a synergistic effect when taken with alcohol. Librium increases the effects of the alcohol, so that - for instance - someone can take Librium and one alcoholic drink and seem as though they've had several drinks. It would also have that effect on an alcoholic - increasing the effects of the alcohol. I wonder if your friend is still drinking along with her medication. Her doctor may want to run a drug test to see what shows up in her urine. It takes 24 hours for alcohol to not show up, and the Librium should be detectable for up to 10 days. There is also the possibility that she is taking other prescribed medications that you don't know about.