Allergy Relief (Diphenhydramine HCl)

Name: Allergy Relief (Diphenhydramine HCl)

What is Allergy Relief (Diphenhydramine HCl) (diphenhydramine)?

Diphenhydramine is an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

Diphenhydramine is used to treat sneezing, runny nose, watery eyes, hives, skin rash, itching, and other cold or allergy symptoms.

Diphenhydramine is also used to treat motion sickness, to induce sleep, and to treat certain symptoms of Parkinson's disease.

Diphenhydramine may also be used for purposes not listed in this medication guide.

What happens if I miss a dose?

Since diphenhydramine is used when needed, you may not be on a dosing schedule. If you are on a schedule, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Important information

When taking diphenhydramine, use caution driving, operating machinery, or performing other hazardous activities. Diphenhydramine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.

Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while taking diphenhydramine.

Do not give this medication 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.

For the Consumer

Applies to diphenhydramine: oral capsules and tablets, parenteral injection

Side effects include:

Sedation, sleepiness, dizziness, disturbed coordination, epigastric distress, thickening of bronchial secretions.

For Healthcare Professionals

Applies to diphenhydramine: compounding powder, injectable solution, oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating

General

The most commonly reported side effects included somnolence, dizziness, and incoordination.[Ref]

Nervous system

Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance
Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsions
Frequency not reported: Paresthesia, dyskinesia/muscle dyskinesia, vertigo, neuritis, incoordination, psychomotor impairment, activation of epileptogenic foci[Ref]

Drowsiness usually diminishes after a few days.[Ref]

Gastrointestinal

Common (1% to 10%): Dry mouth
Frequency not reported: Gastrointestinal disturbance, nausea, vomiting, constipation, diarrhea, dyspepsia, epigastric distress[Ref]

Other

Common (1% to 10%): Fatigue
Frequency not reported: Lassitude, tinnitus, acute labyrinthitis, asthenia, chills, impaired performance (including impaired driving, work, and/or information processing)[Ref]

Psychiatric

Rare (0.01% to 0.1%): Confusion, depression, sleep disturbances
Frequency not reported: Paradoxical excitation/excitation, agitation, increased energy, restlessness, nervousness, euphoria, anxiety, hallucinations, insomnia, irritability[Ref]

Cardiovascular

Rare (0.01% to 0.1%): Palpitations, hypotension, arrhythmia
Frequency not reported: Tachycardia, chest tightness, extrasystoles[Ref]

Hematologic

Rare (0.01% to 0.1%): Blood disorders
Frequency not reported: Hemolytic anemia, thrombocytopenia, agranulocytosis[Ref]

Hypersensitivity

Rare (0.01% to 0.1%): Hypersensitivity reactions
Frequency not reported: Angioedema, anaphylactic shock[Ref]

Hepatic

Rare (0.01% to 0.1%): Liver dysfunction[Ref]

Dermatologic

Frequency not reported: Rash, urticaria, skin rashes, erythema, photosensitivity, pruritus, drug rash, excessive perspiration[Ref]

Respiratory

Frequency not reported: Dyspnea, thickening of bronchial secretions, throat tightening, wheezing, nasal stuffiness, dry nose or throat[Ref]

Genitourinary

Frequency not reported: Urinary hesitancy/difficulty/retention, dysuria, early menses[Ref]

Ocular

Frequency not reported: Blurred vision, dry eyes, diplopia[Ref]

Metabolic

Frequency not reported: Increased appetite, anorexia[Ref]

Musculoskeletal

Frequency not reported: Muscle twitching/weakness[Ref]

Some side effects of diphenhydramine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Usual Adult Dose for Motion Sickness

Oral:
-Prescription formulations: 25 to 50 mg orally 3 to 4 times a day, with the first dose given 30 minutes before exposure to motion and repeated before meals and upon retiring throughout the duration of the journey.

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.

Use:
-Active and prophylactic treatment of motion sickness

Liver Dose Adjustments

Data not available

Diphenhydramine Breastfeeding Warnings

Use is not recommended. -According to some authorities: Use is contraindicated. Excreted into human milk: Yes Comments: -The effects in the nursing infant are unknown. -This drug may affect milk production, especially at high doses given early in the postpartum period and/or when used concomitantly with a sympathomimetic drug.

Administrative Information

LactMed Record Number

96

Last Revision Date

20130907

Disclaimer

Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

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