Inclusion Criteria:  Patients undergoing primary unilateral total hip arthroplasty (THA) in spinal anaesthesia in standardized fast-track setting Habitual use of angiontensin-Converting Enzyme Inhibitors (ACEIs) and/or angiotensin 2 receptor blockers (ARBs) on any indication Patients > 18 Patients that understand and speak Danish Patients that have provided written informed consent  Exclusion Criteria:  Alcohol abuse Any type of substance abuse Chronic pain treated by habitual use of opioids Habitual use of anxiolytic, antidepressant and/or antipsychotic drugs History of cerebral apoplexy or transitory cerebral ischemia History of previous orthostatic intolerance or hypotension History of diabetes mellitus History of following diseases of the autonomic nervous system: Parkinson disease, multiple sclerosis, multiple system atrophy, autonomic neuropathies Cognitive dysfunction Dementia American Society of Anesthesiologists (ASA) > 3