Sildenafil

Sildenafil Clinical Information

How Sildenafil Works

Sildenafil is a phosphodiesterase type-5 (PDE5) inhibitor. It works by enhancing the body’s natural erectile response — relaxing smooth muscle in the blood vessels of the penis when sexual stimulation triggers nitric oxide release. Sildenafil does not cause an erection on its own; sexual stimulation is required. Onset is typically 30–60 minutes; duration is approximately 4 hours.

Indications

• Erectile dysfunction (ED) in adult men
• Certain forms of pulmonary arterial hypertension (PAH) — different brand, different dosing, not the indication addressed here

Do Not Use If You Take Nitrates

Combining sildenafil with any nitrate medication can cause a sudden, life-threatening drop in blood pressure. This is the most important safety point on this page. Nitrates include:

• Nitroglycerin (sublingual tablets, sprays, patches, ointment, IV)
• Isosorbide mononitrate (Imdur, Monoket)
• Isosorbide dinitrate (Isordil, Dilatrate-SR)
• Amyl nitrate / amyl nitrite (recreational “poppers”)

If you have ever been prescribed any of these for chest pain or heart disease, tell your provider before starting any PDE5 inhibitor.

Other Contraindications

• Riociguat (Adempas) or other guanylate cyclase stimulators
• Recent heart attack or stroke (within 6 months)
• Unstable angina or severe heart failure
• Severely uncontrolled high or low blood pressure
• Severe liver impairment
• Known hereditary degenerative retinal disorder (e.g., retinitis pigmentosa)
• Known allergy to sildenafil or its excipients

Use with Caution If You Have

• Coronary artery disease or any cardiac condition where sexual activity itself is inadvisable
• History of priapism (prolonged erection) or anatomical penile deformity
• Sickle cell anemia, multiple myeloma, or leukemia (priapism risk)
• Bleeding disorders or active peptic ulcer
• Hearing impairment

Drug Interactions

Sildenafil interacts with several common medications — dosage may need adjustment, or use may be inadvisable. Tell your provider if you take:

• Alpha-blockers (tamsulosin/Flomax, doxazosin, terazosin) — for prostate or blood pressure
• Other blood-pressure medications
• HIV protease inhibitors (ritonavir, indinavir)
• Strong CYP3A4 inhibitors: ketoconazole, itraconazole, clarithromycin, erythromycin
• Cimetidine
• Recreational substances (especially “poppers”; see contraindications)

Common Side Effects

• Headache
• Facial flushing
• Indigestion / upset stomach
• Stuffy or runny nose
• Transient vision changes (blue tinge, light sensitivity)
• Back pain or muscle aches
• Dizziness

When to Seek Emergency Care

Call 911 or go to the nearest emergency room if you experience:

• An erection lasting more than 4 hours (priapism) — requires immediate intervention to prevent permanent damage
• Sudden vision loss in one or both eyes
• Sudden hearing loss or significant hearing change
• Severe chest pain, shortness of breath, or fainting during or after use

How DMHealth Prescribes Sildenafil

1. Free virtual consultation — discuss goals, history, and any prior ED treatment
2. Cardiovascular & medication screen — explicit confirmation that you take no nitrates or other contraindicated medications
3. Provider evaluation by Diana Medina, MMS, PA-C, under the medical direction of Luis Campillo, MD
4. Prescription shipped discreetly via a verified compounding pharmacy when appropriate
5. Dose titration — sildenafil dosing is individualized; start at the lowest effective dose
6. Follow-up to assess efficacy and any side effects, and adjust as needed

Sildenafil is a prescription medication. Self-sourcing from unverified online sellers without a clinician evaluation is unsafe and illegal.