Diphenhydramine (2)

What Diphenhydramine (2) is used for

Quoted from the “Indications and Usage” section of the FDA-approved label.

Diphenhydramine hydrochloride in the oral form is effective for the following indications: Antihistaminic For allergic conjunctivitis due to foods; mild, uncomplicated allergic skin manifestations of urticaria and angioedema; amelioration of allergic reactions to blood or plasma; dermatographism …

— FDA label: Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026. Read the full label on DailyMed →

Label quoted: the one for the most common form (solution, oral), Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc.; it covers 2 products in the FDA NDC Directory. The side effects, interactions, dosage and pregnancy quotes below come from this same label.

The FDA has 31 labels for products of this medicine (different makers and forms); uses can differ between them. Check the label that comes with your own medicine.

This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.

Boxed warning

A boxed warning (“black box”) is the FDA’s strongest warning on a drug label, for serious or life-threatening risks.

The label quoted above has no boxed warning.

0 of 31 FDA labels for this medicine have a boxed warning.

Diphenhydramine (2) side effects

Quoted from the “Adverse Reactions” section of the FDA-approved label. Tell your doctor about any side effect that worries you.

The most frequent adverse reactions are underscored. 1. General: Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of the mouth, nose and throat. 2. Cardiovascular System: Hypotension, headache, palpitations, tachycardia, extrasystoles. 3. Hematologic System: Hemolytic anemia, thrombocytopenia, agranulocytosis. 4.

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Nervous System: Sedation, sleepiness, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paresthesia, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, neuritis, convulsions. 5. GI System: Epigastric distress, anorexia, nausea, vomiting, diarrhea, constipation. 6. GU System: Urinary frequency, difficult urination, urinary retention, early menses. 7. Respiratory System: Thickening of bronchial secretions, tightness of chest or throat and wheezing, nasal stuffiness. To report SUSPECTED ADVERSE REACTIONS, contact Annora Pharma Limited at 1-866-495-1995 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

— FDA label: Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026. Read the full label on DailyMed →

Diphenhydramine (2) drug interactions

Quoted from the “Drug Interactions” section of the FDA-approved label. Tell your pharmacist about every medicine, vitamin and herbal product you take.

Diphenhydramine hydrochloride has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc.). MAO inhibitors prolong and intensify the anticholinergic (drying) effects of antihistamines.

— FDA label: Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026. Read the full label on DailyMed →

Diphenhydramine (2) dosage

Quoted from the “Dosage and Administration” section of the FDA-approved label. Your own dose is the one your doctor prescribes: do not change it on your own.

DOSAGE SHOULD BE INDIVIDUALIZED ACCORDING TO THE NEEDS AND THE RESPONSE OF THE PATIENT. A single oral dose of diphenhydramine hydrochloride is quickly absorbed with maximum activity occurring in approximately one hour. The duration of activity following an average dose of diphenhydramine hydrochloride is from four to six hours. Adults 25 to 50 mg three to four times daily. The nightime sleep aid dosage is 50 mg at bedtime.

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Pediatric Patients, other than premature infants and neonates 12.5 mg to 25 mg three or four times daily. Maximum daily dosage not to exceed 300 mg. For physicians who wish to calculate the dose on the basis of body weight or surface area, the recommended dosage is 5 mg/kg/24 hours or 150 mg/m 2 /24 hours. Data are not available on the use of diphenhydramine hydrochloride as a nighttime sleep-aid in children under 12 years. The basis for determining the most effective dosage regimen will be the response of the patient to medication and the condition under treatment. In motion sickness, full dosage is recommended for prophylactic use, the first dose to be given 30 minutes before exposure to motion and similar doses before meals and upon retiring for the duration of exposure

— FDA label: Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026. Read the full label on DailyMed →

Diphenhydramine (2) in pregnancy

Quoted from the pregnancy part of the FDA-approved label. Ask your doctor before you take any medicine while pregnant or planning a pregnancy.

Reproduction studies have been performed in rats and rabbits at doses up to 5 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to diphenhydramine hydrochloride. There are, however, no adequate and well- controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

— FDA label: Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026. Read the full label on DailyMed →

When Diphenhydramine (2) should not be used

Quoted from the “Contraindications” section of the FDA-approved label.

Use in Neonates or Premature Infants This drug should not be used in neonates or premature infants. Use in Nursing Mothers Because of the higher risk of antihistamines for infants generally, and for neonates and prematures in particular, antihistamine therapy is contraindicated in nursing mothers. Antihistamines are also contraindicated in the following conditions Hypersensitivity to diphenhydramine hydrochloride and other antihistamines of similar chemical structure.

— FDA label: Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026. Read the full label on DailyMed →

Diphenhydramine (2) overdose

Quoted from the “Overdosage” section of the FDA-approved label. If someone may have taken too much, call Poison Help at 1-800-222-1222 (or 911 in an emergency).

Antihistamine overdosage reactions may vary from central nervous system depression to stimulation. Stimulation is particularly likely in pediatric patients. Atropine-like signs and symptoms, dry mouth; fixed, dilated pupils; flushing and gastrointestinal symptoms may also occur. If vomiting has not occurred spontaneously, the patient should be induced to vomit. This is best done by having him drink a glass of water or milk after which he should be made to gag.

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Precaution against aspiration must be taken, especially in infants and children. If vomiting is unsuccessful, gastric lavage is indicated within 3 hours after ingestion and even later if large amounts of milk or cream were given beforehand. Isotonic or 1/2 isotonic saline is the lavage solution of choice. Saline cathartics, as milk of magnesia, by osmosis draw water into the bowel and therefore are valuable for their action in rapid dilution of bowel content. Stimulants should not be used. Vasopressors may be used to treat hypotension.

— FDA label: Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026. Read the full label on DailyMed →

Forms and how it is given

Companies that list this medicine

Labelers in the FDA NDC Directory: the company named on the package (maker or distributor), with the number of prescription products.

• Fresenius Kabi USA, LLC5 products
• Remedyrepack Inc.4 products
• Medical Purchasing Solutions, LLC4 products
• Micro Labs Limited3 products
• Hikma Pharmaceuticals USA Inc.2 products
• Camber Pharmaceuticals, Inc.2 products
• HF Acquisition Co LLC, DBA HealthFirst2 products
• Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.2 products
• PAI Holdings, LLC dba PAI Pharma2 products
• Cardinal Health 107, LLC2 products
• A-S Medication Solutions2 products
• Sportpharm LLC1 product
• Gland Pharma Limited1 product
• HF Acquisition Co. LLC, DBA Health First1 product
• Avenacy, LLC1 product
• Armas Pharmaceuticals Inc.1 product
• ProPharma Distribution1 product
• Henry Schein, Inc.1 product
• Sagent Pharmaceuticals1 product
• Redmont Pharmaceuticals, LLC1 product

FDA approval history

• ANDA: Abbreviated New Drug Application: how a generic version is approved.

Generic approvals (10)

• ANDA080817West-Ward Pharms Int · November 27, 1972
• ANDA087513Pharm Assoc · February 10, 1982
• ANDA040466App Pharms · May 28, 2002
• ANDA091526Fresenius Kabi USA · March 26, 2013
• ANDA205723Micro Labs · August 22, 2018
• ANDA218448Gland · March 20, 2024
• ANDA205336Avet Lifesciences · June 24, 2025
• ANDA219845Micro Labs · August 22, 2025
• ANDA205337Avet Lifesciences · November 14, 2025
• ANDA219470Annora Pharma · June 17, 2026

Shortage status

The FDA drug shortage list does not show these products.

FDA Drug Shortages database →

Recalls

From FDA enforcement reports, matched by the product’s NDC code. A recall usually covers specific lots only: check the lot number on your package and ask your pharmacist. Do not stop a medicine on your own.

1. April 13, 2022 · Class II · Terminated · D-1101-2022

   cGMP deviations: Temperature abuse

   Diphenhydramine HCl oral solution, USP, 25 mg/10 mL UD, packaged in a) 10 mL unit dose cups (NDC 0121-0978-10), b) 100-count box (NDC 0121-0978-00), Rx only, MFG: Pharmaceutical Associates Inc. — Mckesson Medical-Surgical Inc. Corporate Office

Official identifiers

Next steps

• Find a pharmacy near youAsk which price applies to you and whether your product is affected by a recall
• Latest FDA drug recallsAll medicines, newest first
• Diphenhydramine sold over the counterDrug Facts label and store brands
• Fresenius Kabi USA, LLCMaker or distributor
• Remedyrepack Inc.Maker or distributor
• Medical Purchasing Solutions, LLCMaker or distributor
• All prescription drugs A to ZSearch by generic, brand or Spanish name

Sources

1. FDA-approved label on DailyMed (National Library of Medicine) — Diphenhydramine hydrochloride, Camber Pharmaceuticals, Inc., effective July 4, 2026; via openFDA, FDA data exported October 30, 2026, retrieved October 31, 2026
2. NDC Directory (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
3. Drugs@FDA (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
4. Drug recall enforcement reports (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 27, 2026, retrieved October 31, 2026
5. Drug shortages (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026

openFDA data is provided by the FDA as is; it may be incomplete. Always rely on the label that comes with your medicine. FDA Enforcement Report search →

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