“Cutler, Kleeman, Dowling & Maxwell (1960), finding a 30% reduction in filtration rate following chlorothiazide administration in four … action was 'probably due to altered body sodium and renal haemodynamics'; but Earley & Orloff (1962), who measured inulin clearance in three patients, found a fall (… two out of six estimations when hydrochlorothiazide ….”