Cymbalta (duloxetine) is supposed to be taken only by people diagnosed with the conditions it is intended for – such as depression or anxiety disorder. However, there are also a number of conditions that may be treated using Cymbalta because if its pain-blocking effects. Make sure you tell your health care provider if soon after starting the treatment you develop suicidal thoughts, panic attacks, irritability, aggressive or hostile behavior, insomnia, restlessness, or agitation. Those are rare but possible symptoms that you may get if the medicine is not watching properly for you. If you are younger than 24, the risk of developing those symptom is a bit higher, so your health care provider will need to see you at regular appointments. Less serious side effects are a lot more likely and include muscle pain, headache, constipation, heartburn, dizziness, vomiting, decreased appetite, tiredness, diarrhea, dry mouth, stomach pain, weakness, drowsiness, or nausea. Always make sure you tell your health care provider if you are using any drugs that can cause interactions, such as selective serotonin reuptake inhibitors, medications for migraine headaches, antidepressants, medications for irregular heartbeat, sleeping pills, quinolone antibiotics, sibutramine, tranquilizers, high blood pressure meds, theophylline, propranolol, antihistamines, nonsteroidal anti-inflammatory drugs, or lithium.