I wouldn't take it- it's probably expired. Also, the dosage is probably too high for a starting dose if it's left over from when you used to take it. After four years, your body needs to re-adjust to the medication. Taking a high dose without building up might make you feel worse rather than better.

Why do you feel the need to take medication after four years of not taking it? I think the better way to address the issue is to talk to a doctor if you think that going back on medication is the right decision. But taking leftover medication on the spur of the moment because you feel like it doesn't sound very healthy in my opinion. It sounds like a desperate action.