-ketamine ball-and-stick model of (R) -ketamine skeletal formula of (S) -ketamine ball-and-stick model of (S) -ketamine Pharmacokinetics Ketamine is absorbable via intravenous , intramuscular , oral , and topical routes due to both its water and lipid solubility. [ 44 ] When administered orally, Ketamine undergoes first-pass metabolism , where it