What are side effects of taking xanax (alprazolam) or loritab if they are not prescribed?

Very dangerous.: Both are controlled substances and should only be taken under the advice physician. Xanax (alprazolam) or Alprazolam is a benzodiazepine medication, is habit forming and can result in sign. Sedation.. Lortab, an opioid, is habit-forming and can result in sign sedation. In larger doses both can cause difficulty breathing, and when used IV in combination are common cause of accidental death by overdose.