Specific compounds present in grapefruit are known to inhibit CYP450 3A4 and may improve the bioavailability of swallowed fentanyl (reportedly up to 75% of a dose) and PecFent is available in two various strengths: a one hundred microgram per spray bottle and also a 400 microgram for each spray bottle. https://kameronwmbqd.wikikali.com/1946118/not_known_details_about_pecfent_utilisation