According to the provisions of the third paragraph of Article 37 of the Criminal Procedure Law, there are only three situations: the crime of endangering national security, the crime of terrorist activities and the crime of especially serious bribery. During the investigation, the defense court shall obtain the permission of the investigation organ when meeting the criminal suspect in custody. In other criminal cases, you don't need permission to meet the suspect.
Therefore, lawyers can meet drug trafficking suspects directly in the detention center without approval.