The most common side effects for adults were headache, decreased appetite, insomnia, nausea, dry mouth, and diarrhea. The most common side effects for teens (aged 13-17) were decreased appetite, nausea, rash, headache, and abdominal pain. The most common side effects for kids (aged 6-12) were rash and decreased appetite. These are not all the possible side effects of Simtriyo. See the Important Safety Information below and talk to your doctor for more details.