Diphenhydramine vs Trimethoprim

## Diphenhydramine vs Trimethoprim: Overview

This comparison examines the pharmacological differences between **Diphenhydramine** and **Trimethoprim**.

## Mechanism of Action

**Diphenhydramine**: First-generation H1 antihistamine with anticholinergic properties.

**Trimethoprim**: Dihydrofolate reductase inhibitor (bacterial selective).

## Pharmacokinetics

**Half-life**: Diphenhydramine — 2-8 hours; Trimethoprim — 8-10 hours.

## Chemical Properties

**Molecular Formula**: Diphenhydramine — C17H21NO; Trimethoprim — C14H18N4O3.

**Molecular Weight**: Diphenhydramine — 255.3550 g/mol; Trimethoprim — 290.3180 g/mol.

**Type**: Diphenhydramine — Small molecule; Trimethoprim — Small molecule.