PDE5 inhibitor

How they work

An erection depends on blood vessels in the penis relaxing so blood can flow in. Sexual stimulation releases a chemical messenger that triggers that relaxation, and the PDE5 enzyme gradually breaks the messenger down. Blocking PDE5 lets the relaxing signal last longer and work more strongly.

The same mechanism relaxes blood vessels elsewhere, which is why some PDE5 inhibitors are also used for pulmonary arterial hypertension under different brand names.

Approved uses and timing

• Erectile dysfunction: sildenafil is typically taken about an hour before sex, and a high-fat meal can delay it. Tadalafil lasts longer and can be taken as needed or once daily.
• Benign prostatic hyperplasia: tadalafil is approved to treat urinary symptoms of an enlarged prostate.
• Pulmonary arterial hypertension: sildenafil and tadalafil are approved under separate brand names and dosing schedules.

Safety: the interactions that matter most

Combining a PDE5 inhibitor with a nitrate medicine, such as nitroglycerin or isosorbide, or with recreational nitrate "poppers," can cause a dangerous drop in blood pressure. Riociguat, certain alpha blockers, some antifungals, antibiotics and HIV medicines also interact.

Common side effects include headache, flushing, indigestion, nasal congestion and back or muscle aches. Seek care right away for an erection lasting more than four hours, sudden vision or hearing loss, or chest pain.

ED can be an early health signal

The American Urological Association advises that erectile dysfunction is a risk marker for underlying cardiovascular disease and recommends checking morning total testosterone in men with ED. A PDE5 inhibitor may be more effective when low testosterone is also treated. A good evaluation looks at heart health, blood sugar and medications, not just the prescription.

At HealifyMD

HealifyMD offers Tadalafil Daily from $99/month and a compounded Triple Action Blend from $149/month, with prices confirmed at your eligibility review. Compounded blends are not FDA-approved. A licensed clinician reviews your health history and current medicines before prescribing.

Who should be cautious

People with recent heart attack or stroke, very low blood pressure, severe liver or kidney disease, or certain inherited eye conditions need careful evaluation before using these medicines. Anyone taking blood pressure drugs, alpha blockers for the prostate or medicines that affect liver enzymes should share a full medication list. Never use a PDE5 inhibitor obtained without a prescription, since products sold that way may be counterfeit or contaminated.