Louboutins do run narrow, but you can stretch them and this one tends to run large so you have to make sure the shoe fits perfectly. I personally am comfortable with 4" platformless heels, so making the jump to 5" was only a matter of getting used to the shoe. With that said, if you go on PurseForum.com and look on the Louboutin section, there are a lot of women there who are very comfortable in their Pigalles and some use it as their everyday shoe.
The short answer: it really depends on if you can handle platformless 4" heels in the first place. If you can't, you can try the Pigalle 100mm which is 4" or try the other models that Louboutin has to offer.