Diferencia entre revisiones de «Diphenhydramine»

(Text replacement - "5 mg" to "5mg")
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(No se muestran 17 ediciones intermedias de 9 usuarios)
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==Adult Dosing==
==Adult Dosing==
*Allergic Reaction
*[[Allergic reaction]]
**Oral: 25-50 mg q4-8h, max 300 mg/day
**Oral: 25-50mg q4-8h, max 300mg/day
**IM/IV: 10-50 mg/dose
**IM/IV: 10-50mg/dose
*Parkinsonian symptoms
*Parkinsonian symptoms
**Oral: 25-50 mg tid-qid
**Oral: 25-50mg tid-QID
**IM/IV: 10-50 mg/dose
**IM/IV: 10-50mg/dose
*Insomnia: 50 mg PO qhs
*[[Insomnia]]: 50mg PO qhs
*Injectable 1% diphenhydramine (10 mg/mL) can be used as a local anesthestic alternative to ester/amide anesthetics<ref>Pavlidakey PG et al. Diphenhydramine as an Alternative Local Anesthetic Agent. J Clin Aesthet Dermatol. 2009 Oct; 2(10): 37–40.</ref>
**Sodium channel blocker mechanism
**1-2 mL of 1% diphenhydramine at a time, to not exceed excessive sedation dose
**Typical vial is 50 mg/mL, so to make 10 mg/mL:
***10 mL NS removed from 50 mL vial
***Add 10 mL of 50 mg/mL diphenhydramine to 40 mL of NS
***Sedation is dose related and is similar to what would be expected for IM doses
***Relative contraindications are the same for IM diphenhydramine administration


==Pediatric Dosing==
==Pediatric Dosing==
*Allergic Reaction
*[[Allergic reaction]]
**Oral/IM/IV: 5mg/kg/day divided q6-8h (1.25-1.67 mg/kg/dose)
**Oral/IM/IV: 5mg/kg/day divided q6-8h (1.25-1.67mg/kg/dose)
**Alternate PO dosing
**Alternate PO dosing
***2-6 yo: 6.25mg q4-6h
***2-6 yo: 6.25mg q4-6h
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==Special Populations==
==Special Populations==
*[[Drug Ratings in Pregnancy|Pregnancy Rating]]: Category B
*[[Drug pregnancy categories|Pregnancy Rating]]: B
*Lactation: Enters breast milk
*Lactation Risk: Enters breast milk
*Renal Dosing: n/a
*Renal Dosing: n/a
*Hepatic Dosing: n/a
*Hepatic Dosing: n/a
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==Adverse Reactions==
==Adverse Reactions==
===Serious===
===Serious===
*[[Anticholinergic toxicity]]
*CNS depression
*CNS depression
*Anticholinergic sx
*Cardiac arrthymias (Sodium channel blockade)
*[[Seizures]]
 
===Common===
===Common===
*Sedation
*Sedation
===Overdose related===
*[[Opsoclonus]] - conjugate irregular and nonrhythmical jerking movements of the eyes was reported in a 20-year-old woman who had ingested 5 grams<ref>NEJM. http://www.nejm.org/action/showMediaPlayer?doi=10.1056%2FNEJMicm1002035&aid=NEJMicm1002035_attach_1&area=&</ref>


==Pharmacology==
==Pharmacology==
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*Excretion: Urine
*Excretion: Urine
*Mechanism of Action: [[Antihistamines]] / H1 blocker
*Mechanism of Action: [[Antihistamines]] / H1 blocker
==Indications by Condition==
''The following table is automatically generated from disease/condition pages across WikEM.''
{{#ask:[[Has DrugName::Diphenhydramine]]
|?Has Indication=Indication
|?Has Dose=Dose
|?Has Context=Context
|?Has Route=Route
|?Has Population=Population
|format=table
|headers=plain
|mainlabel=-
|sort=Has Indication
|limit=50
}}


==See Also==
==See Also==
*[[Antihistamines]]
*[[Anticholinergic toxicity]]


==References==
==References==
Lexicomp
<references/>
<references/>
[[Category:Pharmacology]]
[[Category:Pharmacology]]

Revisión actual - 21:55 20 mar 2026

General

  • Type: Antihistamines / H1 blocker
  • Dosage Forms: Oral, IM, IV
  • Common Trade Names: Benadryl

Adult Dosing

  • Allergic reaction
    • Oral: 25-50mg q4-8h, max 300mg/day
    • IM/IV: 10-50mg/dose
  • Parkinsonian symptoms
    • Oral: 25-50mg tid-QID
    • IM/IV: 10-50mg/dose
  • Insomnia: 50mg PO qhs
  • Injectable 1% diphenhydramine (10 mg/mL) can be used as a local anesthestic alternative to ester/amide anesthetics[1]
    • Sodium channel blocker mechanism
    • 1-2 mL of 1% diphenhydramine at a time, to not exceed excessive sedation dose
    • Typical vial is 50 mg/mL, so to make 10 mg/mL:
      • 10 mL NS removed from 50 mL vial
      • Add 10 mL of 50 mg/mL diphenhydramine to 40 mL of NS
      • Sedation is dose related and is similar to what would be expected for IM doses
      • Relative contraindications are the same for IM diphenhydramine administration

Pediatric Dosing

  • Allergic reaction
    • Oral/IM/IV: 5mg/kg/day divided q6-8h (1.25-1.67mg/kg/dose)
    • Alternate PO dosing
      • 2-6 yo: 6.25mg q4-6h
      • 6-12 yo: 12-25mg q4-6h
      • >12 yo: Adult dosing

Special Populations

  • Pregnancy Rating: B
  • Lactation Risk: Enters breast milk
  • Renal Dosing: n/a
  • Hepatic Dosing: n/a

Contraindications

  • Allergy to class/drug

Adverse Reactions

Serious

Common

  • Sedation

Overdose related

  • Opsoclonus - conjugate irregular and nonrhythmical jerking movements of the eyes was reported in a 20-year-old woman who had ingested 5 grams[2]

Pharmacology

  • Half-life: Children 5 hours, Adults 9 hours, Elderly 13.5 hours
  • Metabolism: Hepatic
  • Excretion: Urine
  • Mechanism of Action: Antihistamines / H1 blocker


Indications by Condition

The following table is automatically generated from disease/condition pages across WikEM.

IndicationDoseContextRoutePopulation
Acute allergic reaction50mgH1 antagonistIV/IM/POAdult
Akathisia50mg PO/IM/IVAnticholinergic, first-linePO/IM/IVAdult
Angioedema50 mg IVAntihistamine (allergic angioedema)IVAdult
Antipsychotic toxicity25-50mg IV/IMDystonic reactionIV/IMAdult
Cannabinoid hyperemesis syndrome50mg IVAdjunct with haloperidolIVAdult
Dystonic reaction25-50mg IV over 2 minAnticholinergic, first-lineIVAdult
Extrapyramidal reaction25-50mg PO or IVAnticholinergic for acute dystonia/akathisiaPO/IVAdult
Headache25-50 mg IVAdjunct to prevent akathisiaIVAdult
Migraine headache12.5-25 mg IVAdjunct to prevent akathisia/EPSIVAdult
Migraine headache25-50 mg IVAdjunct to prevent akathisiaIVAdult
Vertigo25-50 mg q4hrAntihistamine (vestibular suppressant)IV/IM/POAdult

See Also

References

  1. ↑ Pavlidakey PG et al. Diphenhydramine as an Alternative Local Anesthetic Agent. J Clin Aesthet Dermatol. 2009 Oct; 2(10): 37–40.
  2. ↑ NEJM. http://www.nejm.org/action/showMediaPlayer?doi=10.1056%2FNEJMicm1002035&aid=NEJMicm1002035_attach_1&area=&
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