There are two types of side effects from the PDE5 inhibitors (Sildenafil, Tadalafil, Vardenafil, Avanafil).
Firstly, PDE5 is used in other places in the body that use similar smooth muscle to the penis, and they are also impacted. The side effects caused by this are common to all the PDE5 inhibitors, but you can still find one works better than another for the desired effect, rather than the undesired side effect.
Secondly, none of them are only PDE5 inhibitors, they all also inhibit some other PDEs, of which there are around 22 types numbered 1-11 with some subtypes too. However, which other PDEs they also inhibit varies for each one, so these cause different side effects.
Acid reflux unfortunately falls into the first category, so all the PDE5 inhibitors can cause it. Your esophagus and lower esophageal sphincter are smooth muscle which use PDE5 to contract, so PDE5 inhibitors reduce their effectiveness at contracting and can cause stomach acid to leak back into the esophagus. Acid reflux isn't good for your esophagus and can cause esophageal cancer over a long period. This side effect usually only happens in people who tend to get acid reflux anyway. You could try a lower dose of Tadalafil. Both the main doses 5mg and 20mg are made in half doses for the purpose of reducing unacceptable side effects, 2.5mg and 10mg.
The muscle pain mentioned earlier is in the second category and is because Tadalafil is also a potent PDE11 inhibitor, and PDE11 is used in lots of places in the body. Actually, it's remarkable Tadalafil is a usable drug due to this, whereas it's actually the most effective of all the PDE5 inhibitors. Muscles use PDE11, and this is why you can get muscle pain. Sometimes a lower dose avoids this side effect while still being sufficiently effective for the desired effects - this is particularly the case with Tadalafil.
Edited by member 26 May 2025 at 13:27
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