About Dr Christopher O'CallaghanIs this you? - Claim your profileDr Christopher O'Callaghan is an Australian-based health professional. Christopher is trained as a Clinical Pharmacologist and practices in Heidelberg. Special interestsHypertension, fainting, low blood pressure, dysautonomia, postural orthostatic tachycardia syndrome, hypertension, high blood pressure, chronic fatigue syndrome, hypermobility syndrome, ambulatory blood pressure monitoring.