Allergy Relief (Diphenhydramine HCl)

Use diphenhydramine exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cold or allergy medicine is usually taken only for a short time until your symptoms clear up.

Do not give diphenhydramine to a child younger than 2 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children. You should not use diphenhydramine to make a child sleepy.

Measure liquid medicine with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

For motion sickness, take diphenhydramine 30 minutes before you will be in a situation that causes you motion sickness (such as a long car ride, airplane or boat travel, amusement park rides, etc). Continue taking diphenhydramine with meals and at bedtime for the rest of the time you will be in a motion-sickness situation.

As a sleep aid, take diphenhydramine within 30 minutes before bedtime.

Call your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache, cough, or skin rash.

This medication can affect the results of allergy skin tests. Tell any doctor who treats you that you are using diphenhydramine.

Store at room temperature away from moisture and heat.

This medication may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Drinking alcohol can increase certain side effects of diphenhydramine.

Ask a doctor or pharmacist before using any other cold, cough, allergy, or sleep medicine. Antihistamines are contained in many combination medicines. Taking certain products together can cause you to get too much of this type of medicine. Check the label to see if a medicine contains an antihistamine.

Diphenhydramine Citrate: 76 mg orally once a day at bedtime

Diphenhydramine Hydrochloride: 50 mg orally once a day at bedtime

Comment:
-Patients should contact their healthcare provider if symptoms of insomnia persist for more than 2 weeks while receiving treatment.

Uses:
-As a nighttime sleep aid
-To reduce difficulty falling asleep
-Relief of occasional sleeplessness

Oral:
Diphenhydramine Citrate: 38 to 76 mg orally every 4 to 6 hours as needed
-Maximum dose: 456 mg/day

Diphenhydramine Hydrochloride: 25 to 50 mg orally every 4 to 6 hours as needed
-Maximum dose: 300 mg/day

Parenteral: 10 to 50 mg deep IM or IV as needed, and may increase to 100 mg if required
-Maximum dose: 400 mg/day

Comment:
-IV injection rates should not exceed 25 mg/min.

Uses:
-Allergic conjunctivitis due to foods
-Mild, uncomplicated allergic skin manifestations of urticaria and angioedema
-Amelioration of allergic reactions to blood or plasma
-Dermatographism
-Therapy for anaphylactic reactions adjunctive to epinephrine and other standard measures after acute manifestations have been controlled
-Temporary relief of runny nose, itchy, watery eyes, sneezing, and itching of the nose/throat due to hay fever or other upper respiratory allergies
-Temporarily relieves runny nose and sneezing due to the common cold

Prescription formulations:
1 month and older:
Oral: 12.5 to 25 mg orally 3 to 4 times a day; alternatively, weight-based dosing of 5 mg/kg orally per day OR body surface area dosing of 150 mg/m2 orally per day may be used
-Maximum dose: 300 mg/day

Parenteral: 1.25 mg/kg deep IM or IV 4 times a day OR 37.5 mg/m2 deep IM or IV 4 times a day
-Maximum dose: 300 mg/day

Oral Over-the-Counter (OTC) formulations:
Diphenhydramine Citrate:
6 to 12 years: 19 to 38 mg orally every 4 to 6 hours as needed
-Maximum dose: 228 mg/day

12 years and older: 38 to 76 mg orally every 4 to 6 hours as needed
-Maximum dose: 456 mg/day

Diphenhydramine Hydrochloride:
2 to 6 years: 6.25 mg orally every 4 to 6 hours as needed
-Maximum dose: 37.5 mg/day

6 to 12 years: 12.5 to 25 mg orally every 4 to 6 hours as needed
-Maximum dose: 150 mg/day

12 years and older: 25 to 50 mg orally every 4 to 6 hours as needed
-Maximum dose: 300 mg/day

Comments:
-IV injection rates should not exceed 25 mg/min.
-To prevent motion sickness, the first dose should be given 30 minutes before exposure to motion and should be repeated before meals and upon retiring throughout the duration of the journey.

Uses:
-Active and prophylactic treatment of motion sickness
-Temporary relief of runny nose, itchy, watery eyes, sneezing, and itching of the nose/throat due to hay fever or other upper respiratory allergies
-Temporarily relieves runny nose and sneezing due to the common cold

Data not available

Safety and efficacy have not been established in newborn or premature infants.

Consult WARNINGS section for additional precautions.

Administration advice:
-Chewable tablets: Tablets should be chewed or allowed to dissolve on the tongue before swallowing.
-Oral powder: Oral powder formulations may be taken with or without water. Patients should avoid dividing the packet in half.

Storage requirements:
-Film-coated tablets: Avoid excessive heat (e.g., 37.8C) or humidity.
-Oral capsules and dissolving tablets: Avoid high humidity and protect from light.
-Oral liquid: Do not refrigerate. Store in the outer carton to protect from light when not in use.
-Parenteral formulations: Protect from light and freezing.

General:
-This drug reduces sleep onset and increases the depth and quality of sleep.
-Parenteral formulations should be reserved for situations where oral treatment is impossible or contraindicated.

Patient advice:
-This drug may cause drowsiness; patients should be told to avoid driving or operating machinery if they feel drowsy or dizzy.

Diphenhydramine is an antihistamine that can be used to treat allergic reactions, relieve motion sickness, as a sleep aid, and to relieve some symptoms of Parkinson's disease. Sedation is a common side effect.

• Diphenhydramine is quickly absorbed after oral administration and peak effects are reached within one hour. The effects of diphenhydramine last from four to six hours.
• When used as a night-time sleeping aid, the usual dosage of diphenhydramine is 50mg at bedtime. A lower dosage may be needed in the elderly.

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