Neurotoxic Reaction to Penicillin and Carbenicillin

Two cases of neurotoxic reaction to penicillin and carbenicillin were observed. Penicillin has long been known to be neurotoxic when given in "massive" doses to patients with reduced renal function. Carbenicillin, a new semisynthetic penicillin, should be considered to have the same neurotoxic potential as penicillin. Signs of neurotoxic reaction should be sought in patients with diminished renal function who receive large doses of penicillin or its derivatives. Appropriate reductions in dose should be made in patients developing signs of neurotoxic reaction to penicillin.