Oral administration of 15 mg of rimantadine/kg yielded peak plasma concentrations of < 50 ng/ml after 3 hours ; a single oral administration of 30 mg/kg yielded mean peak plasma concentrations of 500 ng/ml with mean bioavailability ( F ) of 25 % , beta-phase half-life of 2.2 + / - 0.3 hours , and clearance of 340 + / - 255 ml/min/kg .
