- History of conditions that might contraindicate or require caution be used in the administration of fentanyl or naltrexone, including: renal impairment, hepatobiliary or pancreatic disease, gastrointestinal obstruction, cardiac disease, obstructive pulmonary disease, acute or severe bronchial asthma, hypercarbia, elevated intracranial pressure, depleted blood volume, paralytic ileus, or hypersensitivity or idiosyncratic reaction to fentanyl, naltrexone, or any opioids.