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Diphenhydramine Dosage Table (eg, Benadryl) (Antihistamine)

Child's Weight (pounds) 20-24 25-37  38-49  50-99  100+   lbs 
 Liquid 12.5 mg ¾​ 1 1 ½ --  tsp 
 Liquid 12.5 mg/5 milliliters (mL) 4 5 7.5 10 -- mL
 Chewable 12.5 mg​​ -- 1 1 ½ 2 4 tablets
 Tablets 25 mg -- ½​ ½ 1 2 tablets
 Capsules 25 mg -- -- -- 1 2 caps

​Indications: Treatment of allergic reactions, nasal allergies, and hives.​

Table Notes:

  • AGE LIMITS: Avoid diphenhydramine under 6 years of age unless instructed by healthcare provider. Non-sedating alternatives (eg, loratadine, cetirizine, fexofenadine) are available over-the-counter and are safer for young children.
  • DOSAGE: Determine by finding child's weight in the top row of the dosage table
    MEASURING the DOSAGE: Syringes and droppers are more accurate than teaspoons. If possible, use the syringe or dropper that comes with the medication. If you use a teaspoon, it should be a measuring spoon. Regular spoons are not reliable. Also, remember that 1 level teaspoon equals 5 mL and that ½ a teaspoon equals 2.5 mL.
  • FREQUENCY: Repeat every 6 hours as needed
  • ADULT DOSAGE: 50 mg
  • CHILDREN’S BENADRYL FASTMELTS: Each fastmelt tablet contains the equivalent of 12.5 mg of Diphenhydramine HCL and dosed the same as chewable tablets
  • RISK of SIDE EFFECTS: May cause drowsiness and paradoxical excitatory. Use caution when driving or operating heavy machinery after dosing due to potential for sedation and decreased alertness. This is especially relevant for teen drivers.


Last Updated
Adapted from My Child Is Sick! Expert Advice for Managing Common Illnesses and Injuries (Copyright © 2011 Barton D. Schmitt, MD, FAAP)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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