Last reviewed · How we verify

Dexchlorpheniramine or Diphenhydramine

Sanofi · FDA-approved active Small molecule

Blocks histamine H1 receptors to reduce allergic and inflammatory responses.

Blocks histamine H1 receptors to reduce allergic and inflammatory responses. Used for Allergic rhinitis, Urticaria and pruritus, Allergic reactions.

At a glance

Generic nameDexchlorpheniramine or Diphenhydramine
SponsorSanofi
Drug classH1 receptor antagonist (first-generation antihistamine)
TargetHistamine H1 receptor
ModalitySmall molecule
Therapeutic areaAllergy/Immunology
PhaseFDA-approved

Mechanism of action

Both dexchlorpheniramine and diphenhydramine are first-generation antihistamines that competitively antagonize H1 histamine receptors on target tissues. This prevents histamine-mediated effects such as itching, urticaria, angioedema, and other allergic symptoms. These agents also cross the blood-brain barrier, producing sedation as a common side effect.

Approved indications

Common side effects

Key clinical trials

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape: