Cetirizine vs Erlotinib

## Cetirizine vs Erlotinib: Overview

This comparison examines the pharmacological differences between **Cetirizine** and **Erlotinib**.

## Mechanism of Action

**Cetirizine**: Second-generation H1 antihistamine.

**Erlotinib**: Reversible inhibitor of EGFR (HER1) tyrosine kinase, blocking autophosphorylation.

## Pharmacokinetics

**Half-life**: Cetirizine — 6.5-10 hours; Erlotinib — 36 hours.

## Chemical Properties

**Molecular Formula**: Cetirizine — C21H25ClN2O3; Erlotinib — C22H23N3O4.

**Molecular Weight**: Cetirizine — 388.8900 g/mol; Erlotinib — 393.4380 g/mol.

**Type**: Cetirizine — Small molecule; Erlotinib — Small molecule.