Drug development and personalized therapy require accurate and frequent monitoring of the metabolic response by living tissues to treatments. In case of high risk side effects, e.g. therapies with interfering anti-cancer molecule cocktails, direct monitoring of the patient’s drugs metabolism is essential as the metabolic pathways efficacy is highly variable on a patient-by-patient basis. Currently, there are no fully mature point-of-care bio-sensing systems for drugs metabolism monitoring directly in blood. The aim of the paper is to investigate solutions to develop point-of-care systems for drugs monitoring in personalized therapy. P450 enzymes are the considered probe molecules as they are key proteins directly involved in drugs metabolism of humans. Sensitivity improvement is ensured by means of enzyme integration onto electrodes structured with carbon nanotubes. Component Off-The-Shelf (COTS) based circuits design is investigated toward bio-chip development. Results show that the proposed circuitry is suitable for the aim and confirm that nanotubes are detection enhancers.