Final answer:
When fluconazole is started in a patient taking warfarin, the prothrombin time (PT) will increase (prolong).
Step-by-step explanation:
When fluconazole is started in a patient taking warfarin, it can affect the prothrombin time (PT). Warfarin is an anticoagulant medication that works by inhibiting the production of vitamin K-dependent clotting factors in the liver. Prothrombin time measures the time it takes for blood to clot and is used to monitor the effectiveness of warfarin therapy. Fluconazole can potentiate the effects of warfarin by inhibiting its metabolism, leading to increased anticoagulant activity. As a result, the prothrombin time will increase (prolong) when fluconazole is started.