Slow database drop in mysql
I have addressed this once before : MySQL database drop insanely slow

My suggestion in that post was this

SET unique_checks = 0;
SET foreign_key_checks = 0;
SET GLOBAL innodb_stats_on_metadata = 0;
DROP DATABASE db_madeintouch;
SET GLOBAL innodb_stats_on_metadata = 1;
SET foreign_key_checks = 1;
SET unique_checks = 1;


If all your data uses InnoDB, this might work for you.

Four years ago, I thought having tons of users was also a symptom.

If a patch was missed, here is another likely suspect: Bug #61188 DROP TABLE extremely slow 


  [15 Aug 2011 22:14] James Day
  
  The fix for this is in MySQL 5.5.15 and is expected to be in 5.1.59. At the time of writing it hasn't yet been added to the  release notes but that should happen soon.
  
  [7 Oct 2011 0:46] John Russell
    Added to changelog:
  
  The DROP TABLE command for an InnoDB table could be very slow, in a
    configuration with a combination of table compression, partitioning,
    and a large buffer pool.


Please give it a try and see tell us if it worked.