Fentanyl TORREX is a short-acting opioid analgesic. In adult patients a dose of 1 μg i.v. fentanyl (base!) per kg bodyweight is required to induce analgesia. In the ICU you have a patient (an adult man weighing 85 kg) who needs to manage an acute pain attack. Fentanyl citrate (salt!) solution with concentration of 50 μg/mL is available. How much (how many mL) of fentanyl citrate have to be given to the patient?

Fentanyl (base) MW = 336.47 g/mol , Fentanyl (citrate) MW = 528.59 g/mol