Amoxicillin is an antibiotic often used for the treatment of a number of bacterial infections. These include middle ear infection, strep throat, pneumonia, skin infections, and urinary tract infections among others. It is taken by mouth, or less commonly by injection. Was prescribed 500mg Cephalexin 3 times a day and had severe diahrea and vomitting. I have taken amoxicillin and penicillin in the past and never had any problems so doctor prescribed Amoxicillin 500 mg 2 times a day, every 12 hours. You should not use this medicine if you have severe kidney disease, if you have had liver problems or jaundice while taking amoxicillin and clavulanate potassium, or if you are allergic to any penicillin or cephalosporin antibiotic, such as Amoxil, Ceftin, Cefzil, Moxatag, Omnicef, and others. If you take Amoxicillin for a long time, your doctor may perform additional tests to check your kidneys, liver and blood are working normally. Amoxicillin Dosage. Take Amoxicillin any time a day with or without food. You meal do not impact the penetration of the drug’s components in blood. Make sure you tell your doctor if you are allergic to penicillin. Amoxicillin is a type of penicillin - do not take it if you are allergic to penicillin. Space your doses out evenly over the day and complete the full course of the antibiotic, even if you feel your infection has cleared up. You can Amoxicillin oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. No, you should not take amoxicillin if you are allergic to penicillin. Amoxicillin belongs to the Penicillin class of antibiotics and must be avoided. For most infections, you'll start to feel better in a few days. The most common side effects of amoxicillin are feeling sick (nausea) and diarrhoea. What should I discuss with my healthcare provider before taking amoxicillin? You should not use this medicine if you are allergic to any penicillin antibiotic, such as ampicillin, dicloxacillin, oxacillin, penicillin, or ticarcillin.