Tablet/oral drops: It causes mild or transient drowsiness, dry mouth, thickened respiratory tract secretions, blurred vision, urinary difficulty or retention, constipation and increased gastric reflux. Occasional gastrointestinal side effects of antihistamines include nausea, vomiting, diarrhea or epigastric pain.
Oral solution: Get emergency medical help if the patient has signs of an allergic reaction including severe reactions and angioedema (serious allergic reaction which causes swelling of the face or throat).