Mexican Xanax is often sold without a prescription, but its composition may differ from the original drug. Such pills may contain low-quality additives or even more dangerous substances, such as fentanyl. The main problem is that without lab analysis, it is impossible to determine how safe it is. Counterfeits can cause serious side effects, including overdose and respiratory failure https://unitedrecoveryproject.com/rehab-blog/mexican-xanax-bars/ . Therefore, it is always worth buying medications only from licensed pharmacies.