Furosemide in patients with heart failure: Shift in dose‐response curves

We studied 10 patients with congestive heart failure to assess the dynamics of their response to 40 mg of furosemide. Patients excreted less sodium than normal controls: 142 ± 36 and 245 ± 16 mEq/4 hr (p < 0.05). Patients delivered the same amount of furosemide into the urine—14.9 ± 2.0 and 18.7 ± 2.1 mg/4 hr (p < 0.20)—but the time course of delivery differed. Normal subjects had a sigmoid‐shaped curve when furosemide excretion rate was related to response. All patients but one had shifts in this curve and for a number of patients the configuration differed substantially from a sigmoid curve. Clinical Pharmacology and Therapeutics (1980) 28, 182–186; doi: 10.1038/clpt.1980.148