Medicine Name: Onimex SF 30mg/200mg Syrup Sugar Free. Composition: Ambroxol (30mg) + Guaifenesin (200mg). Side Effects: Nausea Vomiting Diarrhea Dizziness Headache Rash Indigestion Bloating Upper abdominal pain Urticaria Itching Sweating Changes in serum aminotransferase levels Tremors Increased heart rate.