Haemolytic Effect of Two Sulphonamides Evaluated by a New Method

Abstract

A technique to investigate drugs which could cause haemolysis in subjects deficient in glucosc-6-phosphate dehydrogenase (~-glucose-6-phosphate: NADP oxidoreductase; G6PD) has been developed. The method is based on the technique of '"CO, evolution during the incubation of normal erythrocytes in the presence of [~-~~C]glucose and their own serum, the latter containing the active metabolites of the drugs received by normal subjects. By this method agents causing a stimulation of the hexosetnonophosphate pathway of normal erythrocytes should be regarded as potentially haemolytic for G6PD-deficient subjects. Two sulphonamides, sulphormethoxine and sulphalene, of which until now no haemolytic effects have been reported, together with chloroquine, have been investigated. While chloroquine does not affect the hexoseinonophosphate shunt of normal erythrocytes, the two sulphoiiamides stimulate this pathway. The results are confirmed by the reduction of the half-life of s ' Cr-labelled G6PD-dcficient red cells (Mediterranean variant) , after administration of the two sulphoiiamides.Human erythrocyte G6PD-deficiency is the most prevalent hereditary red cell eiizyme defect. Subjects with this X-linked defect are susceptible to haemolytic anaemia after exposure to drugs such as primaquine and sulphoiiamides (Kirkinan, 1968). Until now, methods to evaluate the haemolytic effects in G6PD-deficient subjects have not been completely satisfactory. In the past years, drugs have been administered in controlled studies to G6PDdeficient subjects (Dern ct al, 1954) but obviously this approach is quite hazardous. The method of transfusion of G6PD-deficient erythrocytes labelled with ' Cr to normal volunteer subjects, followed by the administration of a test drug, seems less hazardous (Dern et d, 1954)~ but a disadvantage could be the transmission of viral hepatitis. Fraser & Vesell(1968) suggested an in vitro method based on the study of the mechanical fragility of erythrocytes in the presence of drug metabolites. More often, the discovery of a haemolytic effect of a new drug occurs fortuitously, during the administration of the drug to a subject with unrecognized G6PD deficiency. Recently Welt et al(1971) studied the effect of primaquine on the hexosemonophosphate pathway (HMP) of normal erythrocytes by the method of l 4 c O 2 evolution during incubation of the erythrocytes in the presence of [ 1-l "C] glucose and homologous serum.Using the method of Welt et al (1971), the effect of two potentially hacmolytic drugs on

Glucose-6-phosphate dehydrogenase deficiency: a historical perspective

“…63 Perhaps the most attractive of these is the use of plasma from a normal subject ingesting the drug and determining whether it increases metabolism by way of the hexose monophosphate shunt. 64 Another area of importance is the most devastating result of G6PD deficiency: kernicterus. There has been a resurgence of severe neonatal jaundice and kernicterus in recent years, and G6PD deficiency is one of the causes.…”

Methylene blue-mediated hexose monophosphate shunt stimulation in human red blood cells in vitro: Independence from intracellular oxidative injury

“…Thus, HMS stimulation capacity of a drug may not serve as a reliable indicator of "hemolytic toxicity", as has been suggested (Welt et al, 1971;Gaetani et al, 1976;Pescarmona et al, 1982). It would appear that those compounds designated "Methylene Blue-like" by Carson et al (1981) may elicit HMS activity elevation without toxic oxidation and, therefore, may be unsuitable for use in hemolytic toxicity screening procedures utilizing the HMS stimulation capacity criterion.…”

“…It has been proposed that the capability of a drug to stimulate the HMS in normal red cells would reflect a potential for hemolytic toxicity in G6PD-deficient erythrocytes (Welt et aI., 1971;Gaetani et al, 1976;Pescarmona et al, 1982). Since it is not the HMS per se that reverses oxidative damage, one must presume that the elevation of HMS activity observed under drug treatment is directly coupled to oxidative challenge (i.e.…”

A New Glucose 6-Phosphate Dehydrogenase Variant (G6PD Thessaloniki) in a Patient with Idiopathic Myelofibrosis

“…The rela tively small functional defect (about 20%) of the pentose phosphate pathway de tected (table 3) in the patient's erythro cytes seems to be inconsistent to the severe enzymatic deficiency (95%), as detected by the maximum G6PD activity measure ments after assays in proper haemolysates. However, it has been reported that haemo lysis in G6PD deficiency, being intimately related to the red blood cell survival, de pends rather on the function of the pen tose phosphate pathway in the intact erythrocyte than on the maximum G6PD activity as assayed in haemolysates [Yo shida, 1973;Gaetani et al, 1974Gaetani et al, , 1976. The possibility that the impaired pentose phosphate pathway function detected by the glucose utilization test was due to 6PGDH deficiency, was excluded after 6PGDH activity measurement.…”