Hi & Welcome. Yes, if taken altogether it may cause harmful interactions. 1. Although it is a rare side effect, taking Trazodone together with Flecainide can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with these medications, whether together or alone. 2. If taken along with Metoprolol, Trazodone may have additive effects in lowering your blood pressure. You may experience headache, dizziness, lightheadedness, fainting, and/or changes in pulse or heart rate. These side effects are most likely to be seen at the beginning of treatment, following a dose increase, or when treatment is restarted after an interruption. Avoid driving, swimming or operating hazardous machinery until you know how the medications affect you, and use caution when getting up from a sitting or lying position. Hope I could answer your queries. Best regards. A feed back is appreciated.