Further evidence of the failure of many antihypertensive agents to meet US FDA draft guidelines on optimal trough:peak ratios was presented at the 2nd International Nifedipine Gastrointestinal Therapeutic System Symposium [Paris, France; June 1994]. This subject was previously covered by Inpharma® following a controversial presentation by Dr Faiez Zannad of Nancy University in France.*According to Dr Zannad, very few ACE inhibitors met the proposed FDA criteria. The subject is now revisited, with evidence from additional studies.