Diphenhydramine - Revision history

MDElliottMD: parser-claude: Diphenhydramine MedTemplate refill, Top 300 stub upgrade

2026-05-23T07:32:29Z

parser-claude: Diphenhydramine MedTemplate refill, Top 300 stub upgrade

← Older revision		Revision as of 07:32, 23 May 2026
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	{{MedTemplate		{{MedTemplate
	\| generic = Diphenhydramine		\| generic = Diphenhydramine (hydrochloride; citrate)
	\| brand = Benadryl		\| brand = Benadryl (oral, injectable, topical), Banophen, Sominex (sleep aid), ZzzQuil, Aler-Dryl
	\| structure =		\| structure =
	\| classes = ~~Antihistamine~~, ~~Deliriant~~		\| classes = [[:Category:Antihistamines\|First-generation antihistamine (ethanolamine)]], [[:Category:Anticholinergics\|Anticholinergic]], [[:Category:Sleep aids\|Sleep aid]], [[:Category:Antiemetics\|Antiemetic]]
	\| ~~mechanism~~ = ~~H1 antagonist~~; ~~muscarinic antagonist~~		\| uses = <vote slug="allergic-conditions-use">Allergic conditions including urticaria and seasonal allergies (OTC and FDA)</vote>, <vote slug="motion-sickness-use">Motion sickness (OTC, FDA)</vote>, <vote slug="insomnia-otc-use">Insomnia, short-term (OTC, FDA)</vote>, <vote slug="acute-dystonia-emergency-use">Acute dystonic reaction from neuroleptics (off-label, IV emergency)</vote>, <vote slug="anaphylaxis-adjunct-use">Anaphylaxis adjunct (FDA, IV; not a substitute for epinephrine)</vote>, <vote slug="parkinson-disease-anticholinergic-use">Parkinson disease tremor (off-label, anticholinergic effect)</vote>
	\| ~~uses~~ =		\| starting_dose = Allergy: 25-50 mg PO every 4-6 hours. Insomnia: 25-50 mg PO at bedtime. IV (acute dystonia, severe allergic reaction): 25-50 mg slow IV push
	\| ~~starting_dose~~ =		\| preparations = Tablets 25, 50 mg; capsules; liquid; chewable; topical cream/gel; injection 50 mg/mL
	\| ~~preparations~~ =		\| fda_max = 300 mg/day (oral)
	\| ~~fda_max~~ =		\| pill_id =
	\| routes =		\| routes = Oral, IV, IM, topical
	\| onset =		\| onset = 15-30 minutes (oral); 1-2 minutes (IV)
	\| duration =		\| duration = 4-6 hours
	\| halflife =		\| halflife = 4-8 hours (longer in elderly, 9-13 hours)<ref name="benadryl-label">FDA Prescribing Information, Benadryl (diphenhydramine hydrochloride), Johnson & Johnson/various, current revision. https://www.accessdata.fda.gov/drugsatfda_docs/label/2007/010661s045lbl.pdf</ref>
	\| bioavailability =		\| bioavailability = ~40-60% (oral, with significant first-pass)<ref name="benadryl-label" />
	\| pregnancy =		\| pregnancy = Older agent with substantial use experience; broadly considered safe in pregnancy<ref name="benadryl-label" />
	\| legal =		\| legal = [[USLegal:Over-the-counter\|OTC]] for most oral and topical formulations; [[USLegal:Prescription only\|Rx-only]] for injectable
	\| ~~intro =~~		\| mechanism = <vote slug="diphenhydramine-mech-claim">First-generation H1 histamine receptor antagonist with substantial central nervous system penetration and '''strong muscarinic acetylcholine receptor antagonism'''. The H1 blockade produces antihistamine and antiemetic effects; the muscarinic blockade produces sedation, anticholinergic burden (dry mouth, blurred vision, urinary retention, cognitive impairment), and at supratherapeutic doses, anticholinergic delirium with classic toxidrome ("blind as a bat, mad as a hatter").</vote> Major Beers-list concern in elderly patients for cognitive and fall risks. CYP2D6 substrate. At massive overdose, also produces sodium channel blockade with cardiac toxicity<ref name="benadryl-label" />.
	\| ~~pharmacokinetics =~~
	\| ~~pharmacodynamics~~ =
	~~\| indications~~ =
	~~\| dosing =~~
	\| effects =
	<effect ref="dry-mouth" author="MDElliottMD"/>		<effect ref="dry-mouth" author="MDElliottMD"/>
	~~\| interactions = <pharmaInteractions/>~~
	~~\| pregnancy_details =~~
	~~\| monitoring =~~
	~~\| counseling =~~
	~~\| anecdotes =~~
	~~\| seealso =~~
	~~\| references =~~
	}}		}}

			== References ==
			<references />

	[[Category:Antihistamines]]		[[Category:Antihistamines]]
	[[Category:~~First-generation antihistamines~~]]		[[Category:Anticholinergics]]
	[[Category:~~Anticholinergics (anti-muscarinic)~~]]		[[Category:Sleep aids]]
	[[Category:~~Deliriants~~]]		[[Category:Antiemetics]]

MDElliottMD: Added effect: Dry mouth

2026-05-17T10:12:21Z

Added effect: Dry mouth

← Older revision		Revision as of 10:12, 17 May 2026
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	\| dosing =		\| dosing =
	\| effects =		\| effects =
			<effect ref="dry-mouth" author="MDElliottMD"/>
	\| interactions = <pharmaInteractions/>		\| interactions = <pharmaInteractions/>
	\| pregnancy_details =		\| pregnancy_details =

MDElliottMD: Comprehensive categorization: +First-generation antihistamines, Anticholinergics (anti-muscarinic), Deliriants

2026-05-15T18:42:18Z

Comprehensive categorization: +First-generation antihistamines, Anticholinergics (anti-muscarinic), Deliriants

← Older revision		Revision as of 18:42, 15 May 2026
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	[[Category:Antihistamines]]		[[Category:Antihistamines]]
			[[Category:First-generation antihistamines]]
			[[Category:Anticholinergics (anti-muscarinic)]]
			[[Category:Deliriants]]

MDElliottMD: Pharmacopedia: add

2026-05-14T03:30:49Z

Pharmacopedia: add <pharmaInteractions/>

← Older revision		Revision as of 03:30, 14 May 2026
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	\| dosing =		\| dosing =
	\| effects =		\| effects =
	\| interactions =		\| interactions = <pharmaInteractions/>
	\| pregnancy_details =		\| pregnancy_details =
	\| monitoring =		\| monitoring =

MDElliottMD: Pharmacopedia: remove contraindications parameter

2026-05-14T02:40:31Z

Pharmacopedia: remove contraindications parameter

← Older revision		Revision as of 02:40, 14 May 2026
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	\| dosing =		\| dosing =
	\| effects =		\| effects =
	~~\| contraindications =~~
	\| interactions =		\| interactions =
	\| pregnancy_details =		\| pregnancy_details =

MDElliottMD: Added empty fda_max parameter to MedTemplate call

2026-05-13T02:32:56Z

Added empty fda_max parameter to MedTemplate call

← Older revision		Revision as of 02:32, 13 May 2026
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	\| starting_dose =		\| starting_dose =
	\| preparations =		\| preparations =
			\| fda_max =
	\| routes =		\| routes =
	\| onset =		\| onset =
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	[[Category:Antihistamines]]		[[Category:Antihistamines]]

MDElliottMD: Expand stub to full MedTemplate parameter set

2026-05-13T01:00:00Z

Expand stub to full MedTemplate parameter set

@@ Line 1: / Line 1: @@
 {{MedTemplate
-| generic           = Diphenhydramine
+| generic            = Diphenhydramine
-| brand             = Benadryl
+| brand              = Benadryl
-| classes           = Antihistamine, Deliriant
+| structure          =
-| mechanism         = H1 antagonist; muscarinic antagonist
+| classes            = Antihistamine, Deliriant
 }}
 [[Category:Antihistamines]]

MDElliottMD: Auto-created stub

2026-05-13T00:00:00Z

Auto-created stub

New page

{{MedTemplate
| generic = Diphenhydramine
| brand = Benadryl
| classes = Antihistamine, Deliriant
| mechanism = H1 antagonist; muscarinic antagonist
}}
[[Category:Antihistamines]]