ACE INHIBITORS AND TETRACYCLINES
The absorption of oral tetracycline (and therefore probably most tetracyclines) is moderately reduced by the magnesium carbonate excipient in some quinapril formulations (e.g. Accupro). (60)
The manufacturers of both drugs recommend avoiding concurrent use. One possible way to accommodate this interaction (as with the interaction between tetracyclines and antacids) is to separate the dosages as much as possible (2 to 3 hours should be sufficient).