Diphenhydramine / Phenylephrine Dosage

Medically reviewed by Drugs.com. Last updated on Jul 22, 2025.

Usual Adult Dose for Allergic Rhinitis

Diphenhydramine 12.5 mg / phenylephrine 5 mg per 10 mL liquid: 20 mL every 4 hours
Maximum dose: 6 doses per 24 hours

Diphenhydramine 25 mg / phenylephrine 10 mg per tablet: 1 tablet every 4 hours
Maximum dose: 6 doses per 24 hours

Usual Adult Dose for Cold Symptoms

Diphenhydramine 12.5 mg / phenylephrine 5 mg per 10 mL liquid: 20 mL every 4 hours
Maximum dose: 6 doses per 24 hours

Diphenhydramine 25 mg / phenylephrine 10 mg per tablet: 1 tablet every 4 hours
Maximum dose: 6 doses per 24 hours

Usual Pediatric Dose for Allergic Rhinitis

Diphenhydramine 6.25 mg / phenylephrine 2.5 mg per 5 mL liquid:
6 to under 12 years: 10 mL every 4 hours
Maximum dose: 6 doses per 24 hours

Diphenhydramine 12.5 mg / phenylephrine 5 mg per 10 mL liquid:
12 years and older: 20 mL every 4 hours
6 to under 12 years: 10 mL every 4 hours
Maximum dose: 6 doses per 24 hours

Diphenhydramine 25 mg / phenylephrine 10 mg per tablet:
12 years and older: 1 tablet every 4 hours
Maximum dose: 6 doses per 24 hours

Usual Pediatric Dose for Cold Symptoms

Diphenhydramine 6.25 mg / phenylephrine 2.5 mg per 5 mL liquid:
6 to under 12 years: 10 mL every 4 hours
Maximum dose: 6 doses per 24 hours

Diphenhydramine 12.5 mg / phenylephrine 5 mg per 10 mL liquid:
12 years and older: 20 mL every 4 hours
6 to under 12 years: 10 mL every 4 hours
Maximum dose: 6 doses per 24 hours

Diphenhydramine 25 mg / phenylephrine 10 mg per tablet:
12 years and older: 1 tablet every 4 hours
Maximum dose: 6 doses per 24 hours

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Precautions

CONTRAINDICATIONS:

• Current use of a monoamine oxidase inhibitor (MAOI) or use within 14 days of stopping a MAOI.
• Concomitant use with any other diphenhydramine-containing products, including topical preparations.

Safety and efficacy have not been established in patients younger than 6 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• Use provided measuring cups for dosing.

Patient advice:

• Take only as directed.
• Avoid drinking alcohol while on this drug.
• Discontinue for nervousness, dizziness, or sleepiness.
• Use caution if driving a motor vehicle or operating machinery.
• If symptoms last over 7 days or are accompanied by fever, seek medical attention.
• If cough lasts over 7 days or comes back, or is accompanied or followed by fever, headache that lasts, or rash, seek medical care promptly.

See also:

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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