Diphenhydramine: Difference between revisions

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* [[acetaminophen]] (paracetamol) for night-time pain relief  
* [[acetaminophen]] (paracetamol) for night-time pain relief  
* expectorants like guaifenesin, or [[Dextromethorphan|dextromethorphan hydrobromide]] in cough products<ref name=":0">{{Cite web|url=https://www.medicines.org.uk/emc/search?q=Diphenhydramine&filters=activeingredients%5B191%5D&offset=1&limit=50&orderBy=product&refreshFilters=true|title=Electronic Medicines Compendium|last=|first=|authorlink=|last2=|first2=|authorlink2=|date=|website=www.medicines.org.uk|archive-url=|archive-date=|url-status=|access-date=2021-02-13}}</ref>
* expectorants like guaifenesin, or [[Dextromethorphan|dextromethorphan hydrobromide]] in cough products<ref name=":0">{{Cite web|url=https://www.medicines.org.uk/emc/search?q=Diphenhydramine&filters=activeingredients%5B191%5D&offset=1&limit=50&orderBy=product&refreshFilters=true|title=Electronic Medicines Compendium|last=|first=|authorlink=|last2=|first2=|authorlink2=|date=|website=www.medicines.org.uk|archive-url=|archive-date=|url-status=|access-date=2021-02-13}}</ref>
* levopenthol, a decongestant and [[Analgesics|pain reliever]]<ref name=":0" /><ref>{{Cite web|url=https://www.drugs.com/international/levomenthol.html|title=Levomenthol|website=Drugs.com|language=en|access-date=2021-02-13}}</ref>
* [[levopenthol]], a decongestant and [[Analgesics|pain reliever]]<ref name=":0" /><ref>{{Cite web|url=https://www.drugs.com/international/levomenthol.html|title=Levomenthol|website=Drugs.com|language=en|access-date=2021-02-13}}</ref>
Other common ingredients include:
Other common ingredients include:
* ethyl (a form of alcohol) especially in cough syrups
* ethyl (a form of alcohol) especially in cough syrups

Revision as of 20:35, January 22, 2022

Two bright pink diphenhydramine tablets (generic form of Benadryl)

Diphenhydramine or diphenhydramine hydrochloride is a commonly used antihistamine, which is also used for coughs, to aid sleep, for certain symptoms of Parkinson's diease, as well as for allergy symptoms, bites, itching and eczema.[1][2] Diphenhydramine is the active ingredient in Benadryl, which is sometimes used as a sleep aid as well as an anti-histamine.[1]

Additional active ingredients[edit | edit source]

Products containing diphenhydramine often contain other ingredients, for example:

Other common ingredients include:

  • ethyl (a form of alcohol) especially in cough syrups
  • food colorings, especially reds and blues[3]

Brand names[edit | edit source]

Diphenhydramine is marketed under many different brand names including:

  • Allermax
  • Banophen
  • Benadryl
  • Benylin Chesty Coughs Original and Benylin Mucus Cough Nights (syrup)
  • Compoz Nighttime Sleep Aid
  • Covonia Nighttime Forumla
  • Diphedryl or Diphenhis
  • Nytol One-A-Night
  • Nytol QuickCaps
  • QlearQuil Nightitme Allergy Relief
  • Siladryl Allergy
  • Silphen Cough
  • Sominex original
  • Tranquil
  • Twilite
  • Vanamine PD
  • Unisom Sleepgels maximum strength
  • Z-Sleep
  • ZzzQuil[1][5][6]

Theory[edit | edit source]

Evidence[edit | edit source]

Dosage[edit | edit source]

The usual dose suggested is:

  • creams for bites, itches or eczema - apply a thin layer once or twice a day
  • allergies and hayfever, itching or as an anti-histamine - 25mg to 25mg, 3 or 4 times a day
  • cough and cold symptoms – diphenhydramine is typically mixed with other medicines, the dose depends on the medicine
  • creams for bites, itches or eczema - apply a thin layer once or twice a day
  • sleep problems or insomnia - 25mg to 50mg[2]

Risks and safety[edit | edit source]

Diphenhydramine has a wide range of side effects include dizziness and drowsiness.[1]

It is described as non-addictive/not habit forming, but recently concerns have been raised about long term use including the reduced effectiveness in the long term, causing people to increase the dose.[7] Theoharides and Stewart (2016) stated that in high risk over 65s taking 50mg for 3 years or 50mg for 3 years was associated with cognitive dysfunction.[7]

Using a product containing diphenhydramine marketed for nighttime pain, coughs or cold and flu also involves the side effects of other active ingredients, or from inactive ingredients such as food colorings.[3][6]

Costs and availability[edit | edit source]

Diphenhydramine is available over the counter, under many different brand names including Benadryl.[1] Diphenhydramine is available in tablet, capsule or syrup/liquid form, and in anti-histamine products as a cream, spray or ointment to be applied to the skin.[8]

In the UK, diphenhydramine is a pharmacy-only medication and is not given on prescription.[3] Diphenhydramine is available under the brand names Benylin Chesty Coughs, Histergan, and Nytol Once-A-Day.[2]

See also[edit | edit source]

Learn more[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 1.4 "Diphenhydramine Uses, Dosage & Side Effects". Drugs.com. Retrieved November 9, 2020.
  2. 2.0 2.1 2.2 "Diphenhydramine (including Nytol Original & Histergan): drowsy antihistamine". National Health Service. September 21, 2018. Retrieved February 14, 2021.
  3. 3.0 3.1 3.2 3.3 3.4 "Electronic Medicines Compendium". www.medicines.org.uk. Retrieved February 13, 2021.
  4. "Levomenthol". Drugs.com. Retrieved February 13, 2021.
  5. "£8.59 - Benylin Chesty Coughs Original 300ml". Weldricks Pharmacy. Retrieved February 12, 2021.
  6. 6.0 6.1 "Covonia Night Time Formula - Summary of Product Characteristics (SmPC)". www.medicines.org.uk. Retrieved February 13, 2021.
  7. 7.0 7.1 Theoharides, TC; Stewart, JM (2016). "Antihistamine and mental status" (PDF). J Clin Psychopharmacol. 36 (3): 195–7.
  8. "Diphenhydramine Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing". www.webmd.com. Retrieved February 13, 2021.