RESUMEN
Osmotic fragility of erythrocytes is increased by a number of commonly used analgesics, antimicrobial and antimalarial drugs, resulting in drug-induced hemolytic anemia. Study of erythrocyte osmotic fragility of control and test blood was determined after 5,10 and 15 days of 0.06 mg/ml/day Isoniazid [INH] administration to test subjects. Isoniazid treated subjects exhibited greater RBC fragility than control in 0.1 to 0.3 hypotonic solutions. Control subjects exhibited only 3 per cent destruction in 0.4 per cent saline; whereas test subjects exhibited 12 and 11 per cent destruction on day 5, and 15 in 0.4 per cent concentration of saline, while 10,13 and 15 per cent destruction in 0.5 per cent saline. The study indicated that following prolonged administration of Isoniazid a great number of osmotically fragile RBCs enter the blood stream