Ritonavir can cause unwanted symptoms such as diarrhea, nausea, vomiting, upper and lower stomach (abdominal) pain, tingling feeling or numbness in hands or feet or around the lips, rash, and feeling weak or tired.1 These are not all the risks and side effects associated with ritonavir.1 This information does not replace talking with your doctor about your medical conditions and treatment before taking ritonavir. Read the important safety information and prescribing information  for warnings and side effects.