I wouldn't say anything to my employer, or write down any meds you are taking. If something shows up in your drug screen, the testing company will call you, then they will call the pharmacy to confirm that you have a valid prescription filled within the last year. If it's valid they will report a negative drug screen.
The problem with telling your employer about illnesses, surgeries or meds you take is that you may find they will scrutinize your performance more than usual, they may be more critical, and you may even be marked for exit before you even make it through orientation. (of course, they will not TELL you any of this)
The reason for the scrutiny is that you may be seen as more of a liability than an asset. Employers are not conerned about YOU (although they may ACT sympathetic), they are concerned with their insurance costs and legal liability.
These days employers can be choosy, the nursing shortage is over.
They don't want employees who may (they think) take too many sick days or even have a drug problem. Employers who require pre-employment drug screens and physicals don't want employees who take controlled substances no matter what the reason is. They are looking for healthy employees. If they were concerned with only illegal substances, they wouldn't be testing for legal, controlled, prescribed meds.
Over the years I have noticed that the more pre-employment screening, testing and digging a facility does, the harder that facility turns out to be to work for. I'm not talking about the work required - the general environment of these facilities is one of mistrust. It trickles down from those who make the rules. Makes for a toxic environment.
Of course, not all employers who require testing are like that, One just needs to be careful and take a good look at who you are working for.
The best facility I ever worked for (stayed for several years) was the first one I ever worked for. The DNS went on her "gut feelings" about people when she hired. If you had the qualifications, if she liked you, and they had an opening, you were hired! It was a wonderful, nurturing environment, especially for new grads. I couldn't wait to go to work every day , my co-workers were like family.
Didn't mean to ramble on..but I'm speaking from experience. You need to protect yourself, you don't want to be marked before you even start.
If you would like to know more, feel free to send me a personal message.