Welcome to HCM ....
I read your query and it seems that Phendimetrazine
35mg is used in treating obesity to reduce weight in body .
Phendimetrazine is known to cause changes in libido (sex drives) if taken for months to years .
This drug will be eliminated from body after 24-36 hours .
I suggest your boy friend to avoid stressful works and to take healthy diet rich in protien and nutrients to increase libido .Antioxidants
helps in improving sexual plessures .
Hope this information is useful for you .