Hi, Nausea and chest tightness are possible side effects of co-amoxiclav, which is a combination antibiotic used to treat bacterial infections. If you are experiencing these symptoms, it s important to speak with your healthcare provider as soon as possible. They may want to evaluate you to determine if you are having an adverse reaction to the medication or if there is another underlying cause. Stopping the medication without first consulting your healthcare provider is not recommended. It s important to complete the full course of antibiotics as prescribed to ensure that the infection is completely eradicated. However, if you are experiencing severe symptoms or an allergic reaction, you should seek medical attention immediately. In the meantime, you may find relief by avoiding fatty or spicy foods, drinking plenty of fluids, and getting enough rest. If the nausea is severe, your healthcare provider may be able to prescribe an anti-nausea medication to help alleviate your symptoms. If the chest tightness persists, your healthcare provider may want to perform further tests to rule out any underlying cardiac issues. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Priyanka, General & Family Physician