Diphenhydramine and Pseudoephedrine
Pronunciation
(dye fen HYE dra meen & soo doe e FED rin)
U.S. Brand Names
Benadryl® Allergy and Sinus Fastmelt™ [OTC]; Benadryl® Allergy/Sinus [OTC]; Benadryl® Children's Allergy and Cold Fastmelt™ [OTC]; Benadryl® Children's Allergy and Sinus [OTC]
Synonyms
Pseudoephedrine and Diphenhydramine
Generic Available
No
Use
Relief of symptoms of upper respiratory mucosal congestion in seasonal and perennial nasal allergies, acute rhinitis, rhinosinusitis, and eustachian tube blockage
Adverse Reactions
See individual agents.
Drug Interactions
Diphenhydramine:
Inhibits CYP2D6 (moderate)
Also see individual agents.
Dosage
Based on
pseudoephedrine component:
Adults: Oral: 60 mg every 4-6 hours, maximum: 240 mg/day
Dental Health: Effects on Dental Treatment
Key adverse event(s) related to dental treatment: Pseudoephedrine: Xerostomia (normal salivary flow resumes upon discontinuation). Chronic use of antihistamines will inhibit salivary flow, particularly in elderly patients; this may contribute to periodontal disease and oral discomfort.
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
Use with caution since pseudoephedrine is a sympathomimetic amine which could interact with epinephrine to cause a pressor response
Mental Health: Effects on Mental Status
Diphenhydramine may cause paradoxical excitation in pediatric patients, and can result in hallucinations, coma, and death in overdose. May cause sedation, sleepiness, dizziness, disturbed coordination, headache, fatigue, nervousness, paradoxical excitement, insomnia, euphoria, or confusion. Pseudoephedrine may cause dizziness, drowsiness, nervousness, and insomnia; may rarely cause hallucinations.
Mental Health: Effects on Psychiatric Treatment
Rare reports of agranulocytosis and thrombocytopenia; use caution with clozapine, carbamazepine, and valproic acid; may increase gastric degradation of levodopa and decrease the amount of levodopa absorbed by delaying gastric emptying. Therapeutic effects of cholinergic agents (tacrine, donepezil, rivastigmine, galantamine) and neuroleptics may be antagonized. Central and/or peripheral anticholinergic syndrome can occur when administered with amantadine, rimantadine, narcotic analgesics, phenothiazines, and other antipsychotics (especially with high anticholinergic activity), tricyclic antidepressants and antihistamines. Pseudoephedrine is contraindicated with MAO inhibitors.
Dosage Forms
Liquid (Benadryl® Children's Allergy and Sinus): Diphenhydramine hydrochloride 12.5 mg and pseudoephedrine hydrochloride 30 mg per 5 mL [contains sodium benzoate; alcohol free, sugar free; grape flavor]
Tablet: Benadryl® Allergy/Sinus: Diphenhydramine hydrochloride 25 mg and pseudoephedrine hydrochloride 60 mg
Tablet, quick-dissolving: Benadryl® Children's Allergy and Cold Fastmelt™, Benadryl® Allergy and Sinus Fastmelt™: Diphenhydramine citrate 19 mg [equivalent to diphenhydramine hydrochloride 12.5 mg] and pseudoephedrine 30 mg [contains phenylalanine 4.6 mg/tablet; cherry flavor]