Diphenhydramine is a Medicine belongs to antihistamines group whose information about Brand can be referenced from   Book : Martindale    Page : 629   Edition : 37,

  ►   Brandname : Benadryl,Cofryl,Snuzaid,Adult Chesty Cough,Child Chesty Cough,Aler-Dryl,AllerMax,Unisom,Betadorm D,Dolestan,Dormutil N

  ►  Strength : Chewable tablets with 12.5  mg, Tablet with 25  mg, Tablet with 50  mg, Capsule with 25  mg, Elixir with 12.5/5  mg/ml, Elixir with 25/5  mg/ml, Injection with 50  mg/ml, Chewable tablets with 25  mg, Capsule with 50  mg, Syrup with 12.5/5  mg/ml, Syrup with 25/5  mg/ml, Disintegrating tablets with 12.5  mg,

Reference of this Medicine for its Strength can be taken from   Book : Basic & Clinical pharmacology    Page : 292   Edition : 12,
A Route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance is applied. Common examples include oral and intravenous administration.

  ►  Route of administration : Oral, IV, IM, Topical,
Reference :-   Book : Martindale    Page : 628   Edition : 37,

Dosing of Medicine differ in Adult & Pediatrics ↓


Adult Dose

S.No Ailment   Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency   Additional Info
1 Oral 25 50 mg t.i.d/q.i.d
2 IM or IV 1 5 % Injection
3 Motion sickness Oral 90 135 mg Dose: Given repeated if necessary at intervals of at least 6 hours, to a maximum of 540 mg daily.

Ref :-  Book : Martindale    Page : 628   Edition : 37,




Pediatric Dose

S.No Ailment   Age Min   Age Max   Weight ( Kg ) Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency  Additional Info  
1 2 Year 6 Year Oral 6.25 mg
2 6 Year 12 Year Oral 12.5 25 mg
3 IV 5 mg/kg Injection
4 IM 5 mg/kg Injection

Ref :- Book : Martindale    Page : 628   Edition : 37,
►  Organ Affected CVS (Myocardial infarction)  

Precaution :- If a Patient is using 'Diphenhydramine' drug in acute kidney injury disease, then Please use with caution   if he ever suffered from allergic rhinitis disease.
►  Side Effect : CNS depression, slight drowsiness to deep sleep, lassitude, Dizziness, incoordination, headache, psychomotor impairment, dry mouth, thickened respiratory-tract secretions, Blurred Vision, urinary retention, constipation, increased gastric reflux, nausea, vomiting, diarrhea, epigastric pain, convulsion, sweating, myalgia, paraesthesia, extrapyramidal effects, tremor, Sleep disturbances, Depression, Confusion, tinnitus, hypotension, hair loss, Rashes, hypersensitivity reactions, bronchospasm, angioedema, anaphylaxis, urinary difficulty, ,
Ref :-   Book : Martindale    Page : 611,627   Edition : 37,

►  Drug Interaction : Drug interaction of Diphenhydramine is with CNS depressant, Barbiturates , Hypnotic , Opoid analgesic , Antipsychotic , Antidepressant , Tricyclic antidepressant , Monoamine Oxidase Inhibitor, Anxiolytics, Sedatives, Alcohol,  Atropine , Metoprolol , Venlafaxine ,
Ref :-   Book : Martindale    Page : 613,628   Edition : 37,


  ►    Mechanism of Drug Drug Interaction :  Sedating antihistamines may enhance the sedative effects of CNS depressants including alcohol, barbiturates, hypnotics, opioid analgesics, anxiolytic sedatives, and antipsychotics. Sedative interactions apply to a lesser extent with the non-sedating antihistamines; they do not appear to potentiate the effects of alcohol, but it should be avoided in excess. Sedating antihistamines have an additive antimuscarinic action with other antimuscarinic drugs, such as atropine and some antidepressants (both tricyclics and MAOIs). Diphenhydramine inhibits the cytochrome P450 isoenzyme CYP2D6 that is partly responsible for the metabolism of some beta blockers including metoprolol and the antidepressant venlafaxine,
Ref :-   Book : Martindale    Page : 613,628   Edition : 37,


►  Absolute Contraindication : Should not drive or operate machinery; alcohol should be avoided   neonates   young children   topical preparations containing antihistamines should not be used on broken or eczematous skin.   

►  Contraindication : nursing mothers, Newborn or premature infants,
Ref :-   Book : Principle of Pharmacology (The Pathophysiologic Basis of Drug Therapy)    Page : 774   Edition : 3,
  ►  Mechanism of Action :   Inverse agonists that bind preferentially to the inactive conformation of the H1 receptor and shift the equilibrium toward the inactive receptor state,
Ref :-   Book : Principle of Pharmacology (The Pathophysiologic Basis of Drug Therapy)    Page : 774   Edition : 3,

Pathway of Dietry Product


​   ► Act.Comp / Nutrient / Food / Herb as follows :- Onion with same pathway,

  ►  Pathway with its reference as follows :-
  • antihistamine effect due to quercetin --- (Pdr For Herbal Medicine. 4th ed. 2016. Print. )

  •   ►  URL -- http://www.travolekar.ru/arch/Pdr_for_Herbal_Medicines.pd,


    Dietry Substance Interactions


    ​   ► This Medicine interact with :- NA



    ContraIndication Dietry Substance


    ​   ► This Medicine contraindicate with :- NA

    ►   Route of Elimination :   Hepatic (Metabolism), Renal,
    Ref :-   Book : Martindale    Page : 628   Edition : 37,


    ►    Plasma Half-life :
      Min value :-   2.4 hours,    Max value :-   9.3 hours,
    Ref :-   Book : Martindale    Page : 628   Edition : 37,

    ►    Peak Plasma Concentration :   Min value :-   1 hours,    Max value :-   4 hours,
    Ref :-   Book : Martindale    Page : 628   Edition : 37,