Sildenafil 25 mg is primarily used to treat erectile dysfunction (ED) by increasing blood flow to the penile, helping men achieve and maintain an erection during sexual activity. It belongs to the phosphodiesterase type 5 (PDE5) inhibitor class of medications. This lower dosage is often prescribed for individuals who experience side effects from higher doses or those with certain health conditions requiring a milder effect. Sildenafil 25 mg may also be used to manage pulmonary arterial hypertension (PAH), improving exercise capacity by relaxing blood vessels in the lungs. Always take it as directed by a healthcare professional for safe use.