Use with caution in heart disease, high blood pressure, hyperthyroidism, diabetes, seizure disorder, and in patients with arrhythmias. May cause tremor/palpitations; stop and seek medical help if severe allergy (rash, swelling, breathing difficulty) occurs. Not for self-medication in children, or if cough persists >7 days, is recurrent, or is associated with high fever, chest pain or blood in sputum—consult a doctor.