Applies to dextromethorphan / phenylephrine: oral liquid.
Do not use dextromethorphan and phenylephrine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.
Get emergency medical help if you have any of these signs of an allergic reaction while taking dextromethorphan / phenylephrine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using dextromethorphan and phenylephrine and call your doctor at once if you have:
fast or uneven heart rate;
severe dizziness or anxiety, feeling like you might pass out;
dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, anxiety, chest pain, uneven heartbeats, seizure).
Common side effects may include:
sleep problems (insomnia); or
feeling nervous, restless, or irritable.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to dextromethorphan / phenylephrine: oral disintegrating strip, oral liquid.
The manufacturer has not provided adverse event information.[Ref]