Ondansetron vs Sildenafil
## Ondansetron vs Sildenafil: Overview
This comparison examines the pharmacological differences between **Ondansetron** and **Sildenafil**.
## Mechanism of Action
**Ondansetron**: Selective 5-HT3 receptor antagonist.
**Sildenafil**: Selective PDE5 inhibitor increasing cGMP.
## Pharmacokinetics
**Half-life**: Ondansetron — 3-5 hours; Sildenafil — 4 hours.
## Chemical Properties
**Molecular Formula**: Ondansetron — C18H19N3O; Sildenafil — C22H30N6O4S.
**Molecular Weight**: Ondansetron — 293.3660 g/mol; Sildenafil — 474.5800 g/mol.
**Type**: Ondansetron — Small molecule; Sildenafil — Small molecule.