A major reason for the failure of cancer chemotherapy is the development of multidrug resistance, which may result from many cellular factors. One of the most prevalent factors is the over-expression of the ATP-Binding Cassette transporter P-glycoprotein (P-gp). This protein mediates the ATP dependent efflux of drugs from resistant cancer cells against considerable concentration gradients and this activity may impact the cellular ATP pool. Generation of ATP in cancer cells is primarily derived from the catabolism of glucose through the glycolytic pathway. The heavy reliance on glycolysis and reduced oxidative phosphorylation prevents full utilisation of the energy in glucose. This strategy in cancer cells ensures a balance between energy production and sufficient biomass production to sustain proliferation. Does the ATP utilisation caused by active P-gp perturb this balance and initiate a distinct metabolic strategy for resistant cells? This investigation will focus on the metabolic strategy of P-gp over-expressing cells following addition of glucose and to monitor the effects of anti-cancer drugs. We have demonstrated that resistant cells display higher levels of glucose uptake and an increased lactate production. Additionally, drug treatment further enhanced glucose uptake, but this observation was not associated with an increase in lactate production. Following drug addition, the overall cellular ATP levels were only altered in the short-term and homeostatic regulation was largely maintained. In summary, the observations suggest that the activity of P-gp may cause shunting of pyruvate towards the TCA cycle and oxidative phosphorylation to counter the demand for ATP.