Prevention of the effects of fentanyl by immunological means

Abstract

INVESTIGATIONS have demonstrated that the pharmacological effects of drugs such as digitalis¹ and paraoxon² can be altered by immunological means. To date, however, all reported attempts to antagonise immunologically the in vivo pharmacological effects of narcotic analgesics (such as morphine) have resulted only in mild attenuation or a partial delay in the onset of action^3–5. To prevent immunologically the effect of a pharmacologically active molecule, sufficient amounts, of specific antibodies must be present so that less than a threshold dose of the free drug remains after combination with the antibodies. Such a condition would be maximised with a drug which can be rendered highly immunogenic and which can exert its pharmacological effect at very low concentrations. We report that it is feasible to prevent the pharmacological effects of the potent narcotic analgesic fentanyl in experimental animals by both passive and active immunisation.