Socialr,

Thanks for your question.  Preterax is a medication used for the treatment of high blood pressure.  It is a combination of an Angiotensin converting enzyme inhibitor, perindopril, and a diuretic, indapamide. 

Melatonin is a substance that is found in our body and is related to sleep.  It helps to induce sleep, as well as aid in the body's temperature and metabolism during sleep. 

As a medication, melatonin is used to help patients fall asleep.  It has also been used to treat high blood pressure and some forms of cancer. 

As far as combining it with other medication, melatonin should not be taken with Luvox (an anti-depressant), Warfarin (a powerful blood thinner), or nifedipine (calcium channel blood pressure medication).  I have not found any contraindication to taking Preterax, or its components, with Melatonin.

I hope this has been helpful.

Martin Cane, M.D.