Tell your doctor if you have: kidney problems, heart disease, lung disease (e.g., asthma, emphysema), high blood pressure, an overactive thyroid, diabetes, emotional problems, history of drug dependency, allergies (especially drug allergies). Use caution performing tasks requiring alertness if this medication causes you to feel drowsy. This medication should be used only if clearly needed during pregnancy. Discuss the risks and benefits with your doctor. Since small amounts of this medication are found in breast milk, consult your doctor before breast-feeding.

Tell your doctor of all over-the-counter and prescription medication you may take, including: blood pressure drugs, antidepressants, sedatives, tranquilizers, sleeping pills, cimetidine. Limit your intake of alcoholic beverages while taking this medication. Do not start or stop any medicine without doctor or pharmacist approval.

Drink plenty of fluids, especially water while taking this medication. It will help to break up mucus and clear congestion

If you miss a dose, take it as soon as remembered; do not take it if it is near the time for the next dose, instead, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.