Why is Sudafed nasal spray blacklisted?

Sudafed nasal spray, which contains the active ingredient phenylephrine, has been blacklisted in some regions due to concerns over its efficacy and safety. Regulatory agencies, such as the FDA, have questioned the effectiveness of phenylephrine in treating nasal congestion, leading to the removal or restriction of products containing this ingredient. Additionally, the potential for misuse and side effects has contributed to its negative perception and regulation.