Itching / Allergies

Dosages for Diphenhydramine (Benadryl) for different weights

Medicine Name: Diphenhydramine (Benadryl) May Give Every 15-19 lbs. 20-24 lbs. 25-37 lbs. 38-49 lbs. 50-99 lbs. 100+ lbs.
Liquid 12.5 mg/ 1 teaspoon (tsp) 6-8 hours 1/2 tsp. 3/4 tsp. 1 tsp. 1-1/2 tsp. 2 tsp. -
Liquid 12.5 mg/ 5 milliliters (mL) 6-8 hours 2.5 mL 4 mL 5 mL 7.5 mL 10 mL -
Chewable 12.5 mg 6-8 hours - - 1 tab. 1-1/2 tab. 2 tab. 4 tab.
Tablets 25 mg 6-8 hours - - 1/2 tab. 1/2 tab. 1 tab. 2 tab.
Capsules 25 mg 6-8 hours - - - - 1 cap. 2 cap.

When to Use. Treatment of allergic reactions, nasal allergies, hives and itching.

Table Notes:

  • DOSE. Find the child's weight in the top row of the dose table. Look below the correct weight for the dose based on the product you have.
  • MEASURE the DOSE. Syringes and droppers are more accurate than teaspoons. If possible, use the syringe or dropper that comes with the medicine. If not, you can get a med syringe at drug stores. If you use a teaspoon, it should be a measuring spoon. (Reason: regular spoons are not reliable.) Keep in mind 1 level teaspoon equals 5 mL and that ½ teaspoon equals 2.5 mL. 
  • ADULT DOSE. 50 mg
  • HOW OFTEN. Repeat every 6 hours as needed.
  • CHILDREN’S BENADRYL FASTMELTS. Each fastmelt tablet equals 12.5 mg. They are dosed the same as chewable tablets.

Dosages for Zyrtec for different weights

Okay to use a generic store brand or equivalent

Zyrtec Frequency 6 mo. - 2 Years 2-5 Years 6-11 Years 12+ Years
Liquid 5 mg/ 5 mL Once Daily 2.5 mL 2.5 mL 5 mL 10mL
Chewable 5 mg tablets Once Daily - - 1 tab. 2 tabs.
Tablets 10 mg Once Daily - - - 1 tab.

Dosages for Claritin for different weights

Okay to use a generic store brand or equivalent

Claritin Frequency Under Age 2 2-5 Years 6+ Years
Suspension 5mg/ 5 mL Once Daily Not Recommended 5 mL 10 mL
Chewable 5 mg tablets Once Daily Not Recommended 1 tablet 2 tablets

When to Use. Treatment of allergic reactions, nasal allergies, hives and itching.

Table Notes:

  • When to Use: Treatment of nasal or eye allergies, hives, itching, and other allergic symptoms.
  • Dose: Find the child's age in the top row of the dose table. Look below the correct age for the dose based on the product you have.
  • Measure the Dose: Syringes and droppers are better to use than teaspoons. If possible, use the syringe or dropper that comes with the medicine. If not, you can get a med syringe at a drug store. If you use a teaspoon, it should be a measuring spoon. Reason: regular spoons are not reliable. Keep in mind 1 level teaspoon equals 5 mL and that ½ teaspoon equals 2.5 mL.
  • How Often: Give once a day in the morning.
  • Adult Dose: 10 mg
  • Plus Side: Causes less sedation than older allergy medicines, like Benadryl. It is long-acting and lasts up to 24 hours.
  • Downside: Doesn't control allergy symptoms as well as older allergy medicines. Use loratadine mainly if drowsiness from Benadryl interferes with function.
  • Use in Countries Outside the U.S.: Dose tables are based on U.S. products. Concentrations may vary in countries outside the U.S. Always check the concentration is the same before using this dose table.

Customized from Itching Allergies v0.1 7/8/2025