Drinking and taking prescribed medication aren't comparable - one is a voluntary, elective activity while the other is a medical necessity. And did it actually cause impairment that you can document? The way you described it, he came to you and requested to be relieved because he felt a potential impairment coming on. If you didn't recognize any impairment before then, he either wasn't impaired, wasn't impaired to the point of noticeability, or you lacked the ability to spot it. And presumably, if he is terminated because he takes a prescription medication that could cause impairment, you set a precedent in which anyone who takes a prescription medication that could cause impairment should be involuntarily terminated, whether they actually experience impairment or not. If they do not take their medication for fear of being terminated, you then could theoretically be held liable for any adverse medical effects that they might experience, like death. You would also need to define which side effects constitute "impairment." Suppose a person was drowsy, drank a lot of coffee, got the jitters and dented a vehicle getting it into a tight parking space. Did the caffeine "impair" them to the point they couldn't perform the job properly? And remember that side effects are invariably identified as potential, not invariable, and that drug companies are likely to list anything that is remotely possible, to protect themselves from liability. Look at how many drugs have the potential side effect of "diarrhea OR constipation."
And the fact that the agency has a one=page screening tool doesn't put the responsibility on the applicant to disclose information that isn't asked for. Six pages will barely scratch the surface.
I'm not trying to rip on you or play devils' advocate, it is just that these types of situations have a lot of ramifications and hasty decisions can lead to a lot of headaches down the road.
And the fact that the agency has a one=page screening tool doesn't put the responsibility on the applicant to disclose information that isn't asked for. Six pages will barely scratch the surface.
I'm not trying to rip on you or play devils' advocate, it is just that these types of situations have a lot of ramifications and hasty decisions can lead to a lot of headaches down the road.