What is the maximum daily dosage of diphenhydramine?

Stacy Wiegman, PharmD

Pharmacy

The maximum daily oral dose of diphenhydramine is 300 mg. for the average healthy adult. A greater amount may lead to an overdose. Signs of an overdose include: confusion, weakness, large pupils, dry mouth, fever, excessive sleepiness, flushing, seizures, blurred vision, ringing in the ears, shaking, insomnia and hallucinations. If you develop any of these symptoms, contact your doctor immediately.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.