Cool How Long Does Phentermine Stay In Hair Ideas. Your doctor will probably start you on a low dose of phentermine and topiramate and increase your dose after 14 days. It is important to note that phentermine.

It takes about 20 hours for half of the drug to leave your system. However, it can take up to four weeks for its full effects to be felt. This medicine does remain in the system for a certain amount of time and can be processed.