Erlotinib vs Sildenafil

## Erlotinib vs Sildenafil: Overview

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

## Mechanism of Action

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

**Sildenafil**: Selective PDE5 inhibitor increasing cGMP.

## Pharmacokinetics

**Half-life**: Erlotinib — 36 hours; Sildenafil — 4 hours.

## Chemical Properties

**Molecular Formula**: Erlotinib — C22H23N3O4; Sildenafil — C22H30N6O4S.

**Molecular Weight**: Erlotinib — 393.4380 g/mol; Sildenafil — 474.5800 g/mol.

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