Tadalafil and erectile dysfunction

What Is Tadalafil And How Does It Work For ED?

Tadalafil, the generic name for the branded Cialis®, is a widely used medication that is commonly prescribed to treat erectile dysfunction. Tadalafil is a type of drug known as a phosphodiesterase 5 (or PDE5) inhibitor. PDE5 inhibitors rose to glory (pun intended) with the launch of Viagra in 1998.

Erections, Hormonal Responses and PDE5

An erection is no simple procedure. In response to a trigger that sexually arouses you, your parasympathetic nervous system (the system that controls bodily functions when you’re at rest) is activated. This kicks off the release of nitric oxide, which increases the production of a molecule called cyclic GMP. Cyclic GMP is responsible for relaxing the smooth muscles inside the blood vessels of your penis, a response that increases blood flow by 20 to 40 times. PDE5 is an enzyme that plays an important role in regulating the flow of blood to certain parts of your body, including the penis. It is also responsible for breaking down the cyclic GMP molecules in order to reverse the erection process.

How Does Tadalafil (and Other PDE5 Inhibitors) Work?

PDE5 inhibitors bind to the cyclic GMP molecule, blocking the breakdown caused by PDE5, while improving the effects of nitric oxide and promoting more blood flow. In simple terms, it relaxes blood vessels and increases blood flow.

These treatments are typically a doctor’s first line treatment for physiological – not psychological  erectile dysfunction.


Tadalafil Dosages

Tadalafil can be taken once daily at low dosages (2.5mg – 5mg) or at higher doses (10mg – 20mg) as needed before sex. Tadalafil stays in the body for a long period of time, so you are able to get erections for up to 36 hours after taking your dose.


How Effective Is Tadalafil?

Erectile function is measured as an erectile function domain score on the International Index of Erectile Function (IIEF-EF). The IIEF classifies the severity of ED into five categories stratified by score:

ED Category




Mild ED


Mild to Moderate ED


Moderate ED


Severe ED



So, how effective is tadalafil? Well, the clinical studies on PDE5 inhibitors have been resounding. There’s clearly a reason doctors use it as a first-line treatment for physiological ED. Numerous clinical studies have proven that tadalafil is an effective treatment for all severities of erectile dysfunction. It has also been shown to significantly enhance erectile function. In fact, a study that looked at 11 analyses involving 2327 men found significant improvements to recorded IIEF-EF scores, with increases of 6.5 points with a 10 mg dosage of tadalafil and 8.6 points with the 20 mg dose. In the global assessment questionnaire, 71% of men taking a 10mg dosage and 84% of those taking a 20mg dose reported improved erection quality. 


The Most Common Side Effects of Tadalafil

Side effects most commonly associated with tadalafil include headaches, flushing, an upset stomach, abnormal vision, a runny or stuffy nose, back and muscle pain, nausea, dizziness, and rash. It can also cause more serious side effects such as:

  • an erection that lasts for more than four hours (priapism)
  • sudden vision loss in one or both eyes
  • sudden hearing loss. Some people may also have ringing in their ears (tinnitus) or dizziness. If you have these symptoms, stop taking Tadalafil and contact a doctor right away

Tadalafil also doesn’t play nicely with certain other medicines and substances – so do not take it if you are using alcohol, alpha blockers, nitrates, and antihypertensives or if you are allergic to tadalafil.

If you’re using tadalafil and experience any side effects, you should stop use immediately and contact your doctor.

If you think you’re experiencing erectile dysfunction, a doctor can correctly diagnose you and talk you through suitable treatment options.


The articles published by &BAM are for informational purposes only and do not constitute medical advice. If you have any medical questions or concerns, you should contact your doctor.



  1. https://pubmed.ncbi.nlm.nih.gov/17305584/
  2. https://www.healthline.com/health/pde5-inhibitors
  3. https://www.ncbi.nlm.nih.gov/books/NBK513278/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2643112/
  5. https://pubmed.ncbi.nlm.nih.gov/12352386/
  6. https://www.sciencedirect.com/topics/medicine-and-dentistry/international-index-of-erectile-function