The scope of practice of the medical radiation practitioner demands knowledge and understanding of the indications, contraindications, warnings, precautions, proper use, drug interactions and adverse reactions of a variety of medications. The risk of patient deterioration or acute emergent event, particularly following contrast administration, makes the command of crash cart medications particularly important. This article explores the pharmacological principles of medications most likely to be required in a medical emergency in the medical radiation department and in particular by the computed tomography (CT) technologist. The article also outlines early warning signs to assist in identifying the emergent or deteriorating patient. The learning outlined is designed to equip medical radiation practitioners with the capacity to identify and respond to a medical emergency typical of the medical radiation department, and to respond to that situation with the appropriate use of emergency medications where appropriate. The ability of medical radiation practitioners to recognise and respond to (including the use of medicines) the deteriorating patient or circumstances of a medically urgent nature are key capabilities required to meet minimum standards for Medical Radiation Practice Board of Australia registration and National Safety and Quality Health Service standards. [ABSTRACT FROM AUTHOR]