3 doctors weighed in:

Strange side effects of benadryl (diphenhydramine)?

3 doctors weighed in
Dr. Lee Perry
Internal Medicine - Allergy & Immunology
2 doctors agree

In brief: Several

The most common side effect of taking too much Benadryl (diphenhydramine) would be excessive drowsiness.
Other possible side effects include dizziness, headache, constipation, urinary retention, and heart palpitations.

In brief: Several

The most common side effect of taking too much Benadryl (diphenhydramine) would be excessive drowsiness.
Other possible side effects include dizziness, headache, constipation, urinary retention, and heart palpitations.
Dr. Lee Perry
Dr. Lee Perry
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