This is a difficult situation you are currently faced with and can I understand how frustrating this delicate matter must be for you. I recommend taking your son to see a Naturopath who will provide you with the assistance this individual case requires. They will also take into consideration your son’s past medical history, family history, diet, lifestyle, hormone levels, medications and supplementation when deciding on a course of action to take.
As there are a number of reasons your son may be displaying this behaviour I do believe that a Naturopath consultation would be beneficial for both of you. Over active sexual desires in men may be related to testosterone levels, prolactin levels or Pituitary gland dysfunction.
Concerning Chaste Tree (Vitex) and its effect on the male reproductive system I can give you some further information which may be of assistance to you. The herb Chasteberry’s name originates from the Latin word castitas (meaning chastity) and agnus meaning lamb. Traditionally the dried fruit of the plant was used in monasteries to help the monks remain celibate, hence the historical name “monks pepper”. It was also used in ancient Greece and Rome to diminish sexual desire by modulating the production of prolactin levels in the Pituitary Gland. An excessive production of prolactin results in a drop in sexual desire in males.
Although there are no known contraindications between the herb Vitex and your sons pharmaceutical medication please speak to your GP or Healthcare professional regarding this. Please also remember as a general rule of thumb to take any herbal medicines at least one hour away from conventional medications.