Wright R O, Magnani B, Shannon M W, Woolf A D
Division of General Pediatrics, Children's Hospital, Boston, Massachusetts, USA.
Ann Emerg Med. 1996 Nov;28(5):499-503. doi: 10.1016/s0196-0644(96)70112-9.
To determine whether N-acetylcysteine (NAC reduces methemoglobin.
We carried out an in vitro laboratory experiment in which five healthy adult volunteers donated blood. Each sample was divided equally among three test tubes. Tube 1 served as a negative control. Sodium nitrite .18 mol/L with dextrose .23 mol/L was added to tube 2 and to tube 3. Next, phosphate-buffered saline solution (PBS) was added to tube 2 and NAC (200 mg/mL) to tube 3. Serial methemoglobin levels were measured over 5.5 hours.
Maximum methemoglobin levels were observed at 1.5 hours for both the NAC-nitrite and the PBS-nitrite sample (62.7% +/- 8.1% and 65.1% +/- 7.0%, respectively; data expressed as mean +/- SD). The mean difference in methemoglobin between NAC-nitrite and PBS-nitrite was significant at 4.5 hours (29.3% +/- 23.0%, P = .046). The mean rate of methemoglobin decline in NAC-nitrite samples was also different from that of PBS-nitrite samples (10.7% +/- 1.0% versus 2.9% +/- 2.3%, P = .002). The rate of decline was linea (zero order) in the NAC nitrite samples and represented by the equation: % change methemoglobin = .18 x time in minutes. Area under the concentration-time curve was also different among groups (P < .05).
In this in vitro model, NAC reduced chemically induced methemoglobin.
