From the reference book, ‘Pharmacological Preparations’ by M.D. Mashkovsky

FENTANYL (Phentanylum).

    1-(2-Feniletil)-4-(N-propionylfenilamino)-piperidin.

As a rule, after the use of neuroleptics and fentanyl, the patient receives a muscle relaxant, his trachea is intubated, and supplemental or artificial respiration is provided using oxygen or a mix of oxygen and nitrous oxide or other inhalation anesthetic agents in low concentrations.  For the support of analgesia it is necessary to introduce 1-3 ml of a 0.005% solution of fentanyl every 10-30 minutes.

For short, non-invasive operations outside the chest and abdominal cavities, when muscle relaxants and neuroleptanalgesia is unnecessary, and spontaneous breathing is maintained, 1 ml of a 0.005% solution of fentanyl is introduced for every 10 to 20 kg of bodyweight.  During these operations, it is necessary to keep track of adequate spontaneous breathing.  It is mandatory to be able at perform tracheal intubation and artificial ventilation of the lungs, should the need arise.  In the absence of the means to perform artificial respiration, the use of fentanyl for neuroleptanalgesia is not allowed...