Tell the doctor everything. If you do not, you run the risk of getting a prescription which you may be sensitive or allergic to, or which might interact adversely with something you are already taking. Withholding information for any reason may prevent you from receiving adequate care. You should be straightforward and give the clearest description possible about the condition which brought you to the doctor's office in the first place. Be candid with your health provider.
Alcohol can have adverse effects, if mixed with prescription drugs.
Tell the doctor if you drink, and how much. If you do, advise the doctor. Some foods may interfere with your body's ability to absorb medications. All of these could indicate you might be particularly sensitive to certain prescriptions. If so, advise your physician.