Diphenhydramine vs Fentanyl

## Diphenhydramine vs Fentanyl: Overview

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

## Mechanism of Action

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

**Fentanyl**: Highly potent synthetic mu-opioid receptor agonist approximately 100 times more potent than morphine.

## Pharmacokinetics

**Half-life**: Diphenhydramine — 2-8 hours; Fentanyl — 2-4 hours.

## Chemical Properties

**Molecular Formula**: Diphenhydramine — C17H21NO; Fentanyl — C22H28N2O.

**Molecular Weight**: Diphenhydramine — 255.3550 g/mol; Fentanyl — 336.4700 g/mol.

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