I have just had an experience that makes me very wary. I got a prescription for a new drug from the doctor, and I actually read the "other ingredients." I would suggest that anyone who is allergic to coconut do this, because the pharmacy is certainly not going to do it for you. Actually, you would have to get a really overly involved pharmacist to even think of such a thing. Luckily, my pharmacist today kept me out of trouble. I don't know how much Sodium Laurel Sulfate is in an average capsule, probably not much, but if you have to take a medicine three times a day, it could possibly mess you up.
I am not kidding here. I have had at least mild allergic reactions to almost every single prescription drug I've taken in the past 4 years, since I developed an allergy to coconut, but of course, I don't think any of them have SLS in them, so I don't know what it really is.
Anyway, I decided to get crazy and look up some random common drugs that may contain SLS. Of course, I don't have time to look them ALL up, so this is just to give you an example. Most drugs don't contain it. Sometimes some dosages don't have the capsules, so all the rules apply, except when they don't, of course! There seems to be no rhyme or reason to the types of drugs that contain it.
CYMBALTA® (duloxetine hydrochloride)
Vibra-Tabs® (doxycycline hyclate, USP)