When I used to smoke, I noticed on occasions that when drinking and smoking together, It would make me feel quite light headed, like feeling drunk, I always put this down to the effect of the cigarettes, besides containing poisonous chemicals in the smoke, don't they constrict blood vessels etc? and the resulting lower level of oxygen to the brain produces this effect. Its not happened since I stopped smoking 15 years ago.
PS for Zacsmaster & zzxxee, if thats what you've been hearing, perhaps you should change the company you keep.