Serum Levels and Clinical Effect of Flucloxacillin in Patients with Staphylococcal Infections

25 patients with infections with penicillinase-producing methicillin-sensitive Staphylococcus aureus strains were treated by oral administration of flucloxacillin. In 12 of the patients the serum concentration was measured after administration of 0.5 or 1.0 g 3 times a day. After the smaller dose the average serum level was 24 μg/ml in fasting patients and 17 μg/ml in those who had taken the drug in association with a meal. The corresponding values after administration of 1.0 g were 35 and 26 μg/ml, respectively. In both groups the peak serum level occurred, on the average, one hour after intake of the antibiotic. In 14 of 16 patients with deep infections the effect of treatment was regarded as good. In 9 patients with skin infections the effect was initially good. Three of the patients complained of malaise, but the symptom could not be ascribed to the antibiotic.