May cause drowsiness—avoid driving or operating machinery. Use with caution in children, elderly, liver or kidney disease, thyroid disorders, hypertension, heart disease, diabetes, glaucoma, enlarged prostate/urinary retention, and asthma/COPD (depending on ingredients). Do not use with other cold/cough products containing similar ingredients (risk of overdose, especially paracetamol). Seek medical help if symptoms persist >3 days, high fever, rash, breathing difficulty, or worsening cough occurs.