Antibiotics are used to fight bacteria while new viruses are the known cause of colds. Therefore, antibiotics are not a specific medicine for colds. 

However, your doctor may still prescribe you some antibiotics if there are other complications. For example, congested nasal sinuses and stagnant substances inside can cause inflammation and bacterial infection. 

The symptoms you experience then are usually a runny or stuffy nose, feeling pain and pressure on the face, headache. In addition, you sometimes get ear infections after a cold and need antibiotics to treat them. 

Symptoms include: earache, fever or feeling of fullness in the ears, tinnitus.