Diphenhydramine

28 interactions 3 explained in plain English
Also sold as: Banophen Benadryl Calagel Reformulated Jun 2019 Compoz Dermamycin Diphedryl Diphenhist Dormin Genahist Kids-Eeze Allergy Nytol Pediaclear Cough Rest Simply Scot-Tussin Allergy Siladryl Simply Sleep Sleep-Eze Sleepinal Sominex Somnapure The Itch Eraser Twilite Unisom Sleep Vanamine Vetadryl Wal-Dryl Allergy Wal-Dryl Childrens Wal-Sleep Z Wal-Som Wal-Som Maximum Strength Z-Sleep ZZZ Sleep Zzzquil
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated Jul 4, 2026 · Editorial policy · Data sources

Sources: FDA prescribing information (Structured Product Labeling), the published literature cited in each entry, DDInter 2.0 (a major open-access drug-interaction database), and legacy DrugBank interaction data distributed by the NIH's RxNav service (decommissioned in 2024) — analyzed and reviewed by our pharmacist team. How we build this library →

Most serious with: Hydromorphone Rectal Buprenorphine Nalbuphine Injection Morphine Injection Fentanyl Transdermal Patch Glucagon Injection / Solution
26 Major 2 Moderate
All (28) Major (26) Moderate (2)

Major

Diphenhydramine Acetaminophen And Codeine Capital® & Codeine Explained Increased risk of paralytic ileus and an increased risk of respiratory and CNS depression Details Diphenhydramine Buprenorphine Belbuca Explained An increased risk of respiratory and CNS depression and an increased risk of paralytic ileus Details Diphenhydramine Butorphanol Injection Butorphic Increased risk of respiratory and CNS depression Details Diphenhydramine Butorphanol Nasal Spray Stadol® NS Increased risk of respiratory and CNS depression Details Diphenhydramine Cetirizine Injection Aller-Tec Increased risk of CNS depression Details Diphenhydramine Cetirizine Ophthalmic Zerviate Increased risk of CNS depression Details Diphenhydramine Diazepam Nasal Spray Valtoco Increased risk of CNS depression Details Diphenhydramine Diazepam Rectal Diastat Increased risk of CNS depression Details Diphenhydramine Esketamine Nasal Spray Spravato Increased risk of sedation Details Diphenhydramine Fentanyl Transdermal Patch Duragesic® Increased risk of paralytic ileus and an increased risk of respiratory and CNS depression Details Diphenhydramine Glucagon Injection Baqsimi Increased risk of gastrointestinal side effects Details Diphenhydramine Glucagon Injection / Solution Baqsimi Increased risk of gastrointestinal side effects Details Diphenhydramine Glucagon Nasal Powder Baqsimi Increased risk of gastrointestinal side effects Details Diphenhydramine Glycopyrronium Topical Cuvposa® An increased risk of anticholinergic side effects Details Diphenhydramine Hydromorphone Injection Dilaudid Increased risk of paralytic ileus and an increased risk of respiratory and CNS depression Details Diphenhydramine Hydromorphone Rectal available generically Increased risk of paralytic ileus and an increased risk of respiratory and CNS depression Details Diphenhydramine Hydroxychloroquine Plaquenil An increased risk of seizures Details Diphenhydramine Lacosamide Injection Motpoly An increased risk of CNS depression Details Diphenhydramine Levodopa Oral Inhalation Inbrija An increased risk of CNS depression Details Diphenhydramine Linezolid Injection Zyvox Increased anticholinergic toxicity effects Details Diphenhydramine Metoclopramide Injection Gimoti Increased risk of CNS depression Details Diphenhydramine Metoclopramide Nasal Spray Gimoti Increased risk of CNS depression Details Diphenhydramine Midazolam Nasal Spray Nayzilam Increased risk of hypoventilation, airway obstruction, desaturation, or apnea Details Diphenhydramine Midazolam Injection Nayzilam Increased risk of hypoventilation, airway obstruction, desaturation, or apnea Details Diphenhydramine Morphine Injection Astramorph® PF Increased risk of urinary retention, severe constipation, and paralytic ileus and an increased risk of profound sedation, respirat... Details Diphenhydramine Nalbuphine Injection Nubain® Increased risk of respiratory and CNS depression; increased risk of paralytic ileus Details

Moderate

Diphenhydramine Amitriptyline Elavil Explained Increased anticholinergic effects (dry mouth, urinary retention) Details Diphenhydramine Clonidine Transdermal Patch Catapres An increased risk of sedation and somnolence Details

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Educational information only, not medical advice. Always confirm interactions with your pharmacist or prescriber before making any change to your medications.