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