I am reviewing the companys drugs and alcohol policy and a question has been raised regarding an employee's disclosure of prescribed drug use, namely some one who is on perminant medication for say diabetes or a heart condition.
Whilst we would expect the said employee to declare any medical condition, should we also be asking what drugs they take??.

I think it is important that you know what the side effects of some medication are, especially if the individual may be risking their own safety or that of others whilst carrying out their usual tasks and taking the medication. A slight change of duties may be necessary for the period they are takeing the medication.
It would also be prudent to know where the medication is stored and what to do if the person requires to take their medication, i.e. diabetics who require a boost of sugar.
It is also good to point out to someone taking prescribed medication to keep it somewhere safe away from where others can get hold of it.

I thought the point of asking this in this circumstance was to establish the possibilities of any false positives.

We have a details A&D policy and all our employees are required to declare there medication before they take it. Their contract of employment requires compliance with the policy and the policy requires this declaration.

Depending on your policy and testing methods asking them to declare medication both over the counter and prescription has got to be part of the policy otherwise you could have someone with side effects which endanger them self or anyone around them.

You need to ensure that they declare the brand of the medication as well - different brands had different issues to consider. (I have seen things as such as RED BULL declared because it is a stimulant just incase)

I have a presentation of A&D including declaration of over the counter and prescription medication from a UK Railway Infrastructure company if that might help, let me know.