Tadalafil vs Sildenafil: How PDE5 Inhibitors Differ

"Doctor, which is better, Cialis or Viagra?" is one of the most popular questions in my consulting room. The answer from research is that their overall effectiveness is similar. The difference lies more in "how you use them" than in "how strong they are". So choosing the right medicine depends on the real life of you and your partner.

How PDE5 inhibitors work

When you are aroused, nerves release nitric oxide, which produces a substance called cGMP. cGMP relaxes the smooth muscle in the penile blood vessels, blood flows in and an erection happens. The PDE5 enzyme breaks cGMP down. These medicines block PDE5, so erections come more easily and last better.

They work especially well for vascular ED, the most common type in middle-aged men. Read more in What causes erection problems, and vascular ED.

Comparing the commonly used medicines

There is also vardenafil, which works in a similar way to sildenafil, and avanafil, which works quickly and has fewer visual side effects, but availability differs from country to country.

Pros and cons of each

Tadalafil

Pros: long duration, no need to time things, so intimacy feels natural; can be used daily; helps prostate symptoms; food has almost no effect.

Cons: some men get back pain or muscle aches. The drug stays in the body a long time, so if chest pain occurs, doctors must wait longer before nitrates can be used (at least 48 hours). Read the details in Tadalafil (Cialis): how it works.

Sildenafil

Pros: used for a long time with a lot of safety data; wears off quickly; suits men who are sexually active now and then and don't want the drug in their body for long.

Cons: you need to plan the timing; a fatty meal slows it down; some men see colours oddly for a while. Read about doses in Sildenafil 50 mg or 100 mg.

Which should you choose?

• You want things to feel natural without timing, or you are sexually active often: tadalafil is usually a good fit.
• You also have an enlarged prostate: low-dose daily tadalafil gives two benefits. See Daily vs on-demand tadalafil.
• You have sex only occasionally and want the drug to wear off quickly: sildenafil is a good choice.
• One didn't work or caused too many side effects: switching to the other helps some men.

The EAU and AUA guidelines agree that the choice of medicine should be based on how often you are sexually active, what you and your partner prefer, other health conditions and side effects, rather than on claims that one is superior.

Contraindications and precautions for all of them

• Never use with nitrates in any form, or with poppers. Read more in Poppers: what they are
• Never use with riociguat
• Take care when combined with alpha-blockers, some antifungals and HIV medicines that contain a booster
• Don't take two of these medicines together, and no more than once a day
• Men with severe heart disease must be assessed first to make sure they are ready for sexual activity
• Go to hospital immediately for an erection lasting more than 4 hours, chest pain, sudden blurred vision or sudden hearing loss (in Thailand call 1669)

Get advice to choose the right medicine

At Dr. Kris Clinic we provide both medicines. The doctor assesses the cause of your ED, your chronic conditions, your current medicines and your lifestyle, then helps you choose the right medicine and dose, with follow-up, at the clinic in Surat Thani or online, with consultations in English available. For the full picture, read Erectile dysfunction (ED).