Phenytoin : Fluconazole inhibits the hepatic metabolism of phenytoin and the conconcomitant administration of fluconazole and phenytoin may increase phenytoin levels to a clinically significant degree. Concomitant repeated administration of 200 mg fluconazole and 250 mg phenytoin intravenously, caused an increase of the phenytoin AUC24 by 75% and Cmin by 128%. If it is necessary to administer both drugs concomitantly, serum phenytoin concentration levels should be monitored and the phenytoin dose adjusted to maintain therapeutic levels and avoid phenytoin toxicity.
Elevated alkaline phosphatase is most commonly caused by liver disease or bone disorders. Testing for ALP primarily consists of obtaining a blood sample from a patient along with several other tests for the disorder in question that may be associated with the increase in ALP in the blood serum.  It is possible to distinguish between the different forms (isoenzymes) of ALP produced by different types of tissues in the body, in order to pinpoint what's causing the increase of ALP, in order to treat the patient for either liver disease or bone disorder. A more rapid way for testing ALP concentration is by using p -nitrophenyl phosphate as substrate.  The required volume of serum is 5 mm 3 . for each testing. The sample is first incubated for 30 min. at 38 °C, in a buffered solution in the presence of p -nitrophenyl phosphate. By the action of ALP, phosphate groups are removed from the substrate and para - nitrophenol is liberated giving off a yellow color in solution which can be measured spectrophotometrically.