Dru Interactions- Pharmaceutical The word pharmaceutical indicates that this interaction has to do with something in the manufacture or preparation of medicine. Smetimes a situation comes, where a doctor is adding some iv injection to a infusion bottle from which fluids are flowing into a patient's vein. If, upon such addition, precipitation happens then that precipitate may flow into the patient's veins and that may cause embolism. Such a reaction is called a pharmaceutical drug interaction. Example: If sodium thiopentone and either vecuronium or pancuronium are simultaneously administered they may form a white precipitate which can flow into intravenous tubing. This precipitate may cause a problem of embolism to the patient.(1) 1. Reference: Deleterious Drug Interactions in Anaesthetic Practice G Shorten Department of Anaesthetics, University Hospital, Cork This blog is free from plagiarism.