Drowsiness, sedation, nervousness, insomnia, dizziness, dry mouth, nose or throat, indigestion (nausea, vomiting), attention and coordination disorders, hallucinations (especially in children), psychomotor disorders, tachycardia, arrhythmia, palpitations, difficulty urination, and allergies (redness of the skin, sometimes accompanied by difficulty breathing, swelling of the face or throat). Serotonin syndrome (very rare) feeling confused, tired, sweating, shaking, sudden muscle contractions, or increased blood pressure.