They are in the same opiate family just different names for the brand name drug.

Now, vicodin and lortab are the same meds with different names. Percocet is not the same as lortab. It's a different med all together. However, they will all show positive for opiates on a drug screen.

J_9 has it right. Lortab is a brand of hydrocodone and acetaminophen. Percocet is a brand of oxycodone and acetaminophen. They're similar drugs, but they're not identical.