Ibuprofen and amoxicillin can be taken together or not. These two drugs are different in nature. Ibuprofen is a non-steroidal anti-inflammatory drug that is used for fever reduction. Amoxicillin, on the other hand, is an antibiotic that is used to kill bacteria. You can use ibuprofen whenever you have a fever and use ibuprofen when your body temperature is over 38.3 degrees, and use amoxicillin when you have a bacterial infection. Ibuprofen should generally not be used for more than 3 days, when you have a fever, and not more than 4 times a day. Amoxicillin is fixed for 3 times a day, and then the course of treatment may be different for different diseases. Tonsillitis is used for about 5 days, and pneumonia may be used for 7-10 days.