Drug class
PDE5 Inhibitors: medications in this class
Medications for erectile dysfunction that increase blood flow.
Overview
PDE5 inhibitors relax the smooth muscle in the penis’s blood vessels so that, with sexual stimulation, an erection can occur and last. Sildenafil acts for a few hours and is taken as needed; tadalafil lasts much longer and can be taken daily at a low dose, which also treats urinary symptoms of benign prostatic hyperplasia. Sildenafil at a different dose is also a treatment for pulmonary arterial hypertension.
Headache, flushing, nasal congestion and indigestion are the common effects. The class must never be combined with nitrate heart medicines, interacts with alpha-blockers such as tamsulosin, and a sudden change in vision or hearing, or an erection lasting more than a few hours, needs urgent care.
None of them works without stimulation, and they do not increase desire.
How the drugs in this class differ when you pay cash
Sildenafil and tadalafil are commodity generics; vardenafil is generic too, avanafil remains a brand. The cash price is the pharmacy’s fee and mark-up, and for these drugs the mark-up varies enormously: the same prescription can differ several-fold between a chain and an independent. The sildenafil tablet approved for pulmonary hypertension is the same molecule as the erectile dysfunction strengths and is sometimes prescribed because it is cheap; the prescriber decides whether that is appropriate.
Quantity limits are an insurance construct; a cash prescription for more tablets per fill spreads the dispensing fee. Brand Viagra and Cialis, and telehealth bundles that mark up the medicine, cost far more than a generic from a competitive pharmacy.
When paying cash beats a copay, and when it does not
Most plans exclude or limit these drugs, so cash is the usual route and comparing pharmacies produces some of the largest differences on this site. Where a plan covers them, a copay for a limited quantity may still be beaten by a cash quote for a larger quantity.
Conditions treated
- Erectile Dysfunction
- BPH
Medications
Which of these is right for a given person is a decision for the prescriber. The guides explain what each drug is, how it is supplied, and why its cash price varies between pharmacies. No page on this site shows a price; prices come from pharmacies responding to your actual prescription.
Questions worth asking
- Would daily tadalafil or as-needed sildenafil suit me better?
- Is it safe with my heart, blood pressure and prostate medicines?
- How many tablets per fill is appropriate for me?
- Should the cause of my erectile dysfunction be investigated?
- What should I do if an erection lasts too long or my vision changes?
How Script Unlock gets you a cash price for a PDE5 Inhibitors prescription
Prices on this site come from pharmacies responding to a real prescription. We do not publish estimated, average or "typical" prices, because none of those would be your price.
- 1You upload your prescription
A photo of your a PDE5 Inhibitors prescription prescription is enough. Nothing is sold on the site; you are asking pharmacies to quote.
- 2Licensed pharmacies respond
Pharmacies that Script Unlock has verified see the request and each can reply with its own cash price for your exact drug, strength and quantity.
- 3You choose and pay the pharmacy
You compare the responses, pick a pharmacy, and pay that pharmacy directly when you collect. Script Unlock never takes a patient payment and never sets the price.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases
- MedlinePlus drug information (National Library of Medicine)
- FDA Orange Book (approved generics and therapeutic equivalence)
- MedlinePlus health topics (NIH)
Written by the Script Unlock editorial team from the sources above. Not yet reviewed by an independent pharmacist. Last checked 2026-10-03.
Script Unlock is a marketplace that lets licensed pharmacies quote a cash price on your prescription. It does not prescribe, dispense or sell medication, does not process patient payments, and does not give medical advice. Always follow the instructions of your prescriber and pharmacist and read the medication guide supplied with your medicine.