Do not give dextromethorphan to a child younger than 4 years old.
Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.
Do not use dextromethorphan if you have used an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), tranylcypromine (Parnate), or methylene blue injection within the past 14 days. Serious, life-threatening side effects can occur if you take dextromethorphan before the MAO inhibitor has cleared from your body.
Do not use any other over-the-counter cough, cold, or allergy medication without first asking your doctor or pharmacist. If you take certain products together you may accidentally take too much of one or more types of medicine. Read the label of any other medicine you are using to see if it contains dextromethorphan. Dextromethorphan will not treat a cough that is caused by smoking, asthma, or emphysema.
Before taking this medicine
Do not use dextromethorphan if you have used an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), tranylcypromine (Parnate), or methylene blue injection within the past 14 days. Serious, life-threatening side effects can occur if you take dextromethorphan before the MAO inhibitor has cleared from your body.
Ask a doctor or pharmacist about using dextromethorphan if you have emphysema or chronic bronchitis.
It is unknown whether dextromethorphan is harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Dextromethorphan may pass into breast milk. Do not use this medication without telling your doctor if you are breast-feeding a baby.
Artificially-sweetened liquid forms of cough medicine may contain phenylalanine. This would be important to know if you have phenylketonuria (PKU). Check the ingredients and warnings on the medication label if you are concerned about phenylalanine.
