HI I have gone through your mail and as you said that you are having severe cough specially during night when you are in bed , and this is for last 6 days you got only little relief by cough syrup ,now you are interested to add some antibiotic, but I would like to suggest you before thinking about antibiotic you should take interest to find out the cause of your cough at night. Usually coughing on lying down on bed is mainly of cardiac origin. So in your case it should be worked out weather your cough is of cardiac disease or due to respiratory tract infection, to confirm this you should contact your physician for doing your clinical examination and some investigations to reach the final diagnosis and treatment. Thanks.