title: Letter: Duration of action of fentanyl.
mesh_terms: D000698:Analgesia; D006348:Cardiac Surgical Procedures; D001026:Coronary Artery Bypass; D005112:Extracorporeal Circulation; D005283:Fentanyl / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000494:pharmacology; D011229:Preanesthetic Medication; D013997:Time Factors
chemical_list: D009020:Morphine; D005283:Fentanyl