May cause drowsiness—avoid driving or operating machinery. Use with caution in asthma/COPD, glaucoma, enlarged prostate/urinary retention, liver disease, and in elderly patients. Not recommended for children without medical advice. Do not use if taking MAO inhibitors (or within 14 days of stopping) due to risk of serious reactions. Seek medical advice if cough persists >7 days, is recurrent, or is accompanied by fever, rash, persistent headache, breathing difficulty, or thick/colored sputum.