Note: This document contains side effect information about diphenhydramine / phenylephrine. Some dosage forms listed on this page may not apply to the brand name Dimetapp Children's Nighttime Cold & Congestion.
Applies to diphenhydramine / phenylephrine: oral liquid, oral suspension extended release, oral tablet.
Do not use diphenhydramine 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, and tranylcypromine, and others.
Use this medicine exactly as directed. Taking too much diphenhydramine can lead to serious heart problems, seizures, coma, or death.
Do not use this medicine to make a child sleepy. Ask a doctor before giving the medicine to a child younger than 6 years old.
Ask a doctor or pharmacist before using any other medicine that may contain diphenhydramine. Taking too much of this medicine can lead to a fatal overdose.
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using this medicine and call your doctor at once if you have:
painful or difficult urination;
fast, pounding, or uneven heartbeats;
a seizure; or
problems with balance or speech.
Common side effects may include:
dizziness, drowsiness, headache;
dry mouth, nose, or throat;
nausea, vomiting, constipation;
blurred vision; or
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 diphenhydramine / phenylephrine: oral disintegrating strip, oral liquid, oral suspension extended release, oral tablet, oral tablet chewable extended release.
The manufacturer has not provided adverse event information.[Ref]