INDICATIONS FOR USE

Sildenafil is FDA-approved for the treatment of erectile dysfunction (ED).

ROUTE OF ADMINISTRATION

• Administered orally in tablet or troche form.

COMMON INITIAL DOSING REGIMENS

• For Erectile Dysfunction: The initial dose is typically 50 mg taken approximately one hour before sexual activity. The dose may be adjusted to 25 mg or 100 mg based on efficacy and tolerability. A maximum dosing frequency of once daily is recommended.

MECHANISM OF ACTION

• Sildenafil is a selective phosphodiesterase type 5 (PDE5) inhibitor. By inhibiting PDE5, it prevents the degradation of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum and pulmonary vasculature.

• For erectile dysfunction, increased cGMP levels lead to smooth muscle relaxation and vasodilation, enhancing blood flow to the penis during sexual stimulation and facilitating erection.

COMMON SIDE EFFECTS

• Cardiovascular: Headache, flushing, and dizziness are common due to systemic vasodilation. Hypotension, tachycardia, and palpitations may also occur, particularly when combined with other vasodilators.

• Ophthalmologic: Visual disturbances, such as bluish vision (cyanopsia), increased light sensitivity, or blurred vision, occur due to inhibition of PDE6 in the retina.

• Gastrointestinal: Dyspepsia, nausea, and diarrhea.

• Respiratory: Nasal congestion and epistaxis.

• Rare but Severe: Non-arteritic anterior ischemic optic neuropathy (NAION), sudden hearing loss, or priapism (prolonged erection requiring medical attention).

CONTRAINDICATIONS

• Absolute: Concomitant use with nitrates (e.g., nitroglycerin) or guanylate cyclase stimulators (e.g., riociguat) due to the risk of severe hypotension. Hypersensitivity to sildenafil or any excipient.

• Relative: Use cautiously in individuals with severe cardiovascular disease, significant hypotension (<90/50 mmHg), recent history of stroke or myocardial infarction, or severe hepatic impairment. Patients with retinitis pigmentosa or predisposition to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia) require additional monitoring.

LEARN MORE

• Evidence hound? Review our comprehensive listing of PubMed direct links to original research related to this medication.