FDA-filed SPL labeling · retrieved through openFDA

Diphenhydramine

Diphenhydramine is an antihistamine used to temporarily relieve hay fever, upper respiratory allergy and common cold symptoms, and (in a topical gel) pain and itching from minor skin problems.

Brand names UnisomSominexSilphenSiladrylBen Tann +11 more
Drug class ⓘ Histamine-1 Receptor Antagonist
Rx/OTC Forms 9 Routes Oral · Topical · Intramuscular; Intravenous · Intramuscular, Intravenous
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 748 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

At a glance
Linked label effectiveJan 14, 2026
Clinical labels in scope ⓘ748
AvailabilityRx/OTC
Earliest approval/marketing year ⓘ1972
FDA-listed product records ⓘ2,124
Boxed warningNone found in compared labels
How we combine label and product data →
✓No current FDA shortage listed · checked Oct 1, 2026
Other forms & routes:
Injection Topical
⭐ Diphenhydramine at a glance The quick version — the full detail is in the Patient Information Guide below.
💊
HelloPharmacist Editorial Team Bottom Line
Diphenhydramine can temporarily ease hay fever, other upper respiratory allergy and common cold symptoms, and the topical gel can ease itching and pain from minor skin problems. It commonly causes drowsiness, so avoid alcohol and be careful driving. Follow the package directions closely, especially for children and older adults.
How we write & review this content — our editorial policy →

📖 Diphenhydramine: Patient Information Guide

A plain-language walkthrough of Diphenhydramine — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.

What Diphenhydramine is used for

▾

Diphenhydramine is used for temporary symptom relief across several products.

  • Hay fever and other upper respiratory allergies: runny nose, sneezing, itchy and watery eyes, itchy nose or throat (oral products)
  • Common cold: runny nose and sneezing (oral products)
  • After Bite Xtra topical gel: pain and itching from minor burns, cuts or scrapes, insect bites, minor skin irritations, and poison ivy, poison oak and poison sumac rashes

How Diphenhydramine works

▾

Diphenhydramine is an antihistamine. It appears to compete with histamine for receptor sites on cells, which helps reduce allergy symptoms. It also has drying (anticholinergic) and sedative effects.

How Diphenhydramine is taken (dosage)

▾

Oral products are generally taken by mouth every 4 to 6 hours as needed, with no more than 6 doses in 24 hours. The amount depends on age and the specific product.

  • Chewable tablets are chewed completely, not swallowed whole.
  • Liquids are measured with the dosing cup provided.
  • Capsules should not be broken.
  • After Bite Xtra gel goes on the skin, up to 3 to 4 times daily.

Follow the package and your prescriber's or doctor's directions.

Diphenhydramine side effects in detail

▾

Common effects include:

  • Drowsiness and sedation
  • Dizziness
  • Dry mouth, nose and throat
  • Poor coordination
  • Fatigue
  • Nausea or stomach upset
  • Excitability, especially in children

Get help for allergic reactions (hives, wheezing, tight chest or throat), trouble urinating, convulsions, confusion or a racing heartbeat.

Diphenhydramine warnings and precautions

▾
  • Drowsiness can impair driving and machinery use.
  • Overdose in children may cause hallucinations, convulsions or death.
  • Older adults are more likely to have dizziness, sedation and low blood pressure.
  • Use caution with glaucoma, stomach ulcer or blockage, enlarged prostate with symptoms, or bladder-neck obstruction.
  • Local tissue damage (necrosis) has been associated with subcutaneous or intradermal use of the injection, and it should not be used as a local anesthetic.

Diphenhydramine interactions: what it interacts with

▾

Diphenhydramine can add to or intensify the effects of other substances.

  • Alcohol: more drowsiness
  • Sedatives, sleeping pills, tranquilizers: additive sedation
  • MAO inhibitors: prolong and intensify drying effects

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

Before taking Diphenhydramine

▾
  • Do not use if allergic to diphenhydramine or similar antihistamines.
  • Not for newborns or premature infants.
  • Contraindicated in nursing mothers.
  • Oral products are not for children under 2 years, and some are not for children under 6.
  • Older adults should be careful about dizziness and sedation.
  • Check with a doctor if you have glaucoma, an enlarged prostate, or stomach or bladder blockage.

Diphenhydramine overdose: if you take too much

▾

Overdose can cause anything from drowsiness and CNS depression to stimulation, which is more likely in children. Other signs include dry mouth, fixed dilated pupils, flushing and stomach symptoms. Seek emergency care right away; treatment is supportive and may include measures to empty the stomach and medicine for low blood pressure.

Pharmacodynamics: what Diphenhydramine does in the body

▾

Diphenhydramine is an antihistamine with drying (anticholinergic) and sedative effects. It appears to compete with histamine at receptor sites on cells.

Pharmacokinetics: how your body processes Diphenhydramine

▾

A single oral dose is absorbed quickly, with peak activity at about one hour. Effects last about four to six hours. It spreads widely through the body, including the brain and spinal cord. Little is excreted unchanged; most is broken down by the liver and almost completely cleared within 24 hours.

How to store Diphenhydramine

▾

store between 20-25°C (68-77°F). Protect from light.

📄 Written from Diphenhydramine’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →

147

Supplements & herbs that interact with Diphenhydramine

147 supplements and herbal products have documented interactions with Diphenhydramine in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.

Severity mix
  • Major · 9
  • Moderate · 119
  • Minor · 19
1,4-BUTANEDIOL Major ACTIVATED CHARCOAL Major BEER Major GAMMA-HYDROXYBUTYRATE (GHB) Major HENBANE Major KAVA Major L-TRYPTOPHAN Major SCOPOLIA Major +139 more
Every supplement checked against Diphenhydramine — ranked by severity The full interaction hub: 9 major · 119 moderate · 19 minor · every one linked to its full report. Check Diphenhydramine against your exact supplements

Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.

🩺 Diphenhydramine: pharmacist answers to common questions

Quick, plain-English answers to the questions patients ask most about Diphenhydramine — the kind of thing our pharmacy team would talk through with you at the counter.

What is diphenhydramine for?

▾
Oral products temporarily relieve hay fever and other upper respiratory allergy symptoms like runny nose, sneezing and itchy, watery eyes. They also ease runny nose and sneezing from a cold. A topical gel like After Bite Xtra is for pain and itching from minor skin problems such as insect bites.

How often can I take it?

▾
Oral forms are generally taken every 4 to 6 hours, with no more than 6 doses in 24 hours. The amount depends on age and the product, so check the package chart or ask me or your doctor.

Will it make me sleepy?

▾
It can. Drowsiness is common, so be careful driving or using machinery. Alcohol, sedatives and tranquilizers make it worse, so avoid them.

Is it safe for kids?

▾
Oral products are not for children under 2 years, and some are not for children under 6. Children can become excitable, and overdose can be very dangerous. Always follow the age directions on the package.

Who should be careful with it?

▾
Check first if you have glaucoma, an enlarged prostate with symptoms, a stomach ulcer or blockage, or trouble emptying your bladder. Older adults are more prone to dizziness and low blood pressure. It is not for nursing mothers.

When should I get help?

▾
Get help for hives, wheezing, or a tight chest or throat, or if you have confusion, convulsions, a racing heartbeat or trouble urinating. Seek emergency care if too much has been taken.

Is Diphenhydramine available over the counter?

▾
Both — Diphenhydramine is sold both over the counter and by prescription, according to its FDA labeling. Lower strengths or certain forms are often available without a prescription, while higher strengths or specialized forms still require one. Ask your pharmacist which version is right for you.

When was Diphenhydramine first available?

▾
Diphenhydramine has been available in the United States since at least 1972, based on FDA approval history (Drugs@FDA) and product marketing records.

Who makes Diphenhydramine?

▾
Diphenhydramine is supplied by 332 manufacturers listed in the FDA NDC Directory, including Walgreen Company, CVS Pharmacy, Rite Aid Corporation.

💬 Answers drafted from Diphenhydramine’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →

🧰 More about Diphenhydramine on HelloPharmacist

📊Diphenhydramine supplement interactions147 checked — ranked by severity 🌿Drug & Supplement CheckerDiphenhydramine vs. vitamins & herbs 💬Ask a PharmacistFree answer, usually < 24h 🔎NDC & pricing lookupFind Diphenhydramine NDCs & costs 🅰️Browse Drugs A–ZLook up any medication

💊 Diphenhydramine forms and strengths (how it comes)

Diphenhydramine is available in 9 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.

Capsule

By mouth
Brands Diphenhist
How this form is used
What it may be used for
  • Banophen capsules temporarily relieve hay fever or other upper respiratory allergy symptoms and common cold symptoms (runny nose, sneezing).
Important instructions
  • Diphenhydramine Hydrochloride capsules are taken every 4 to 6 hours, with no more than 6 doses in 24 hours.
  • Diphenhydramine Hydrochloride capsules should not be broken.
  • Diphenhydramine Hydrochloride capsules are not for children under 6 years.
Available strengths 4 strengths
25 mg 50 mg 50 mg/21 50 kg
705 FDA-listed product records ⓘ

Tablet

By mouth
Brands Benadryl
Available strengths 3 strengths
25 mg 25 mg/25 mg 50 mg
643 FDA-listed product records ⓘ

Oral solution

By mouth
Brands Allergy Allergy Relief BENADRYL Allergy childrens allergy Childrens Allergy Relief Childrens Benadryl DYE-FREE ALLERGY
How this form is used
Important instructions
  • BENADRYL Allergy oral solution is taken every 4 to 6 hours, up to 6 doses in 24 hours.
  • BENADRYL Allergy oral solution should be measured only with the enclosed dosing cup.
  • Childrens Benadryl DYE-FREE ALLERGY is not for children under 2 years and is used for ages 2 to 5 only if directed by a doctor.
Available strengths 10 strengths
2.5 mg/mL 6.25 mg/mL 12.5 mg/5 mL 12.5 mg/10 mL 12.5 mg/15 mL 25 mg/5 mL
Show 4 more strengths Show fewer strengths
25 mg/10 mL 50 mg/3 mL 50 mg/20 mL 50 mg/30 mL
529 FDA-listed product records ⓘ

Chewable tablet

By mouth
Brands Allergy Relief Childrens Allergy Relief Walmart
How this form is used
Important instructions
  • Walmart chewable tablets are chewed completely and not swallowed whole.
  • Childrens Allergy Relief chewable tablets are chewed or crushed completely before swallowing.
  • Walmart and Childrens Allergy Relief chewables are taken every 4 to 6 hours, up to 6 times in 24 hours.
  • Walmart and Childrens Allergy Relief chewables are not for children under 2 years.
Available strengths 2 strengths
12.5 mg 25 mg
94 FDA-listed product records ⓘ

Injection

Into a muscle · Into a vein
Available strengths 1 strength
50 mg/mL
72 FDA-listed product records ⓘ

Topical cream, ointment or gel

By mouth · On the skin
Brands After Bite Xtra
How this form is used
What it may be used for
  • After Bite Xtra gel temporarily relieves pain and itching from minor burns, cuts or scrapes, insect bites, minor skin irritations, and poison ivy, oak and sumac rashes.
Important instructions
  • After Bite Xtra gel is applied to the affected area, not more than 3 to 4 times daily, in adults and children 2 and older.
  • After Bite Xtra gel in children under 2 should only be used after consulting a doctor.
Available strengths 10 strengths
2 mg/100 mL 12.5 mg 20 mg/g 20 mg/mL 25 mg 0.4 g/20 g
Show 4 more strengths Show fewer strengths
1.14 g/57 g 2 g/100 g 2 g/100 mL 2.03 g/100 g
33 FDA-listed product records ⓘ

Other oral form

By mouth
Available strengths 2 strengths
12.5 mg 25 mg
13 FDA-listed product records ⓘ

Topical solution

On the skin
Available strengths 1 strength
20.3 g/L
2 FDA-listed product records ⓘ

📊 Diphenhydramine on the U.S. market: products, makers and brands

How Diphenhydramine appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.

9
Dose forms ⓘ
332
Manufacturers
40
Brand names
2,124
FDA-listed product records ⓘ
1972
First marketed ⓘ

FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

Also listed with the FDA, not a patient dose form: Powder (20) · Kit (4) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.

Walgreen Company7%
CVS Pharmacy6%
Rite Aid Corporation4%
Wal-Mart Stores Inc4%
Lil' Drug Store Products, Inc.4%
Target Corporation4%
Other makers71%

Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

📈 How widely Diphenhydramine is used (Medicaid data)

A general measure of how commonly Diphenhydramine is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.

Think of this as a proxy for how widely Diphenhydramine is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.

1,303,409
Medicaid prescriptions filled (Q1–Q4 2025)
$34.8M gross Medicaid reimbursement (before mandatory rebates — net cost is lower)

How commonly is Diphenhydramine prescribed? Of the 1,597 medications we measure, Diphenhydramine ranks #142 by Medicaid prescriptions — more than 91% of them.

Where Diphenhydramine ranks among the drugs we measure · Q1–Q4 2025 · neighbors ±5
Total prescriptions — #142 of 1,597
#137 Simvastatin 1,357,663 Rx #138 Tretinoin 1,345,058 Rx #139 Tretinoin Topical 1,344,781 Rx #140 Dapagliflozin 1,339,664 Rx #141 Benztropine 1,314,428 Rx #142 Diphenhydramine 1,303,409 Rx #143 Dexamethasone Injectio... 1,290,031 Rx #144 Ketorolac Injection 1,259,288 Rx #145 Dicyclomine 1,233,412 Rx #146 Albuterol and Ipratrop... 1,217,671 Rx #147 Diazepam 1,216,820 Rx

Utilization by Diphenhydramine product

Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.

The 2.5 mg/mL oral solution is the most-dispensed Diphenhydramine product — about 29% of these Medicaid prescriptions.

diphenhydramine hydrochloride 2.5 MG/ML Oral Solution Most dispensed

383,271 Medicaid prescriptions (Q1–Q4 2025) 29% of Diphenhydramine prescriptions shown $3.1M gross reimbursement (before rebates) ≈ $8.21 per prescription (gross)

Summed across the 37 of 269 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1049906

diphenhydramine hydrochloride 25 MG Oral Capsule

259,953 Medicaid prescriptions (Q1–Q4 2025) 20% of Diphenhydramine prescriptions shown $3M gross reimbursement (before rebates) ≈ $12 per prescription (gross)

Summed across the 14 of 356 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1049909

diphenhydramine hydrochloride 50 MG/ML Injectable Solution

172,217 Medicaid prescriptions (Q1–Q4 2025) 13% of Diphenhydramine prescriptions shown $13.3M gross reimbursement (before rebates) ≈ $77 per prescription (gross)

Summed across the 2 of 13 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1049633

1 ML diphenhydramine hydrochloride 50 MG/ML Injection

166,857 Medicaid prescriptions (Q1–Q4 2025) 13% of Diphenhydramine prescriptions shown $11.9M gross reimbursement (before rebates) ≈ $71 per prescription (gross)

Summed across the 7 of 42 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1723740

diphenhydramine hydrochloride 50 MG Oral Capsule

164,709 Medicaid prescriptions (Q1–Q4 2025) 13% of Diphenhydramine prescriptions shown $1.8M gross reimbursement (before rebates) ≈ $11 per prescription (gross)

Summed across the 7 of 246 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1020477

diphenhydramine hydrochloride 25 MG Oral Tablet

150,359 Medicaid prescriptions (Q1–Q4 2025) 12% of Diphenhydramine prescriptions shown $1.3M gross reimbursement (before rebates) ≈ $8.64 per prescription (gross)

Summed across the 19 of 480 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1049630

1 ML diphenhydramine hydrochloride 50 MG/ML Prefilled Syringe

3,479 Medicaid prescriptions (Q1–Q4 2025) <1% of Diphenhydramine prescriptions shown $322,679 gross reimbursement (before rebates) ≈ $93 per prescription (gross)

Summed across the 1 of 4 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1049289

diphenhydramine hydrochloride 12.5 MG Chewable Tablet

24 Medicaid prescriptions (Q1–Q4 2025) <1% of Diphenhydramine prescriptions shown $241 gross reimbursement (before rebates) ≈ $10 per prescription (gross)

Summed across the 1 of 44 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1049900

diphenhydramine hydrochloride 1.67 MG/ML Oral Solution

23 Medicaid prescriptions (Q1–Q4 2025) <1% of Diphenhydramine prescriptions shown $263 gross reimbursement (before rebates) ≈ $11 per prescription (gross)

Summed across the 1 of 127 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1248354

Other Diphenhydramine products — combination packs and listings not yet matched to a specific clinical product (kept visible so every prescription is accounted for)

2,517 Medicaid prescriptions (Q1–Q4 2025) <1% of Diphenhydramine prescriptions shown $19,037 gross reimbursement (before rebates) ≈ $7.56 per prescription (gross)

Summed across the 2 of 587 listed NDC products with Medicaid activity.

Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.

Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Diphenhydramine, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 91 of 2,168 listed Diphenhydramine NDCs with Medicaid activity.

🔍 Compare Diphenhydramine products

A representative set of FDA-listed product records for Diphenhydramine — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)

Showing 200 of 2,124 products — FDA National Drug Code Directory. See every product, package size and price: browse all 2,124 Diphenhydramine NDCs →

RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Diphenhydramine RxCUI 3498 11 dose forms · 28 strengths
  1. Dose form (SCDF) Chewable Tablet RxCUI 371893 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 12.5 MG RxCUI 1049900 hydrochloride 25 MG RxCUI 2046528 tannate 25 MG RxCUI 1251787
  2. Dose form (SCDF) Disintegrating Oral Tablet RxCUI 477246 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 12.5 MG RxCUI 882504 hydrochloride 25 MG RxCUI 1093098
  3. Dose form (SCDF) Injectable Solution RxCUI 371895 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 0.5 MG/ML RxCUI 1249715 hydrochloride 1 MG/ML RxCUI 1249717 hydrochloride 50 MG/ML RxCUI 1049633
  7. Dose form (SCDF) Oral Tablet RxCUI 371892 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 10 MG RxCUI 1310475 hydrochloride 25 MG RxCUI 1049630 hydrochloride 30 MG RxCUI 1310483 hydrochloride 50 MG RxCUI 1085945
  9. Dose form (SCDF) Topical Cream RxCUI 377689 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 10 MG/ML RxCUI 1049888 hydrochloride 20 MG/ML RxCUI 1050077
  10. Dose form (SCDF) Topical Gel RxCUI 377976 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 0.02 MG/MG RxCUI 1049880
  11. Dose form (SCDF) Topical Spray RxCUI 377318 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 10 MG/ML RxCUI 1049898 hydrochloride 20 MG/ML RxCUI 1050080

Look up RxCUI 3498 in the RxCUI Atlas →

RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.

🏷️ Diphenhydramine brand names

Unisom Sominex Silphen Siladryl Ben Tann Benadryl PediaCare Children's Allergy Dicopanol Nytol Aler-Dryl Diphenhist Diphenadryl Pardryl Hydramine Dytan Diphenylin

🏭 Who makes Diphenhydramine: manufacturers and labelers

Walgreen Company 72 CVS Pharmacy 64 Rite Aid Corporation 46 Wal-Mart Stores Inc 44 Lil' Drug Store Products, Inc. 38 Target Corporation 38 Amerisource Bergen 37 Topco Associates LLC 35 Walgreens 33 Meijer Distribution Inc 33 Spirit Pharmaceuticals Llc 32 A-S Medication Solutions 30 Dolgencorp, Inc. (DOLLAR GENERAL & REXALL) 28 Dolgencorp, LLC 27 L.N.K. International, Inc. 27 Strategic Sourcing Services LLC 26 P & L Development, LLC 26 WinCo Foods, LLC 25 Kroger Company 25 QUALITY CHOICE (Chain Drug Marketing Association) 25 Major Pharmaceuticals 24 The Procter & Gamble Manufacturing Company 23 H E B 23 Cardinal Health 110, LLC. DBA Leader 20

…and 16 more on the FDA NDC directory.

Diphenhydramine drug class (RxNorm)

Diphenhydramine belongs to the Histamine-1 Receptor Antagonist class.

Pharmacologic class Histamine-1 Receptor Antagonist
Drug family (ATC) Propionic acid derivatives, Antihistamines for topical use, Aminoalkyl ethers
How it works Histamine H1 Receptor Antagonists

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

🔬 Sources for this Diphenhydramine page

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective Jan 14, 2026
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Diphenhydramine.
📈
Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
🚨
Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Diphenhydramine after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
748
NDC products indexed
2,124
Distinct labelers/manufacturers represented
332
Linked representative label ⓘ
NorMed
Linked label effective
Jan 14, 2026
Composite sections available
18
Linked SPL Set ID
38786a65-a12b-4479-b63c-b7c15410da04
Linked SPL Document ID
675ce74c-0894-4272-85ba-086f33459a9a
Open the linked representative label on DailyMed ↗
NDC package records associated with this linked SPL 1

How we combine label and product data

HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 748 FDA-filed SPL label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.

For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. NorMed is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.

This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.