Drug Interaction of Minoxidil and Himplasia with Oral Anti Diabetic Drug Sitagliptin in Diabetic Rats

Aim and Objective: Sitagliptin is given as an oral antidiabetic drug to treat Diabetes Mellitus. Minoxidil and himplasia may be co-prescribed along with sitagliptin to treat hypertension and BPH respectively. As such no information is available regarding the interaction taking place between sitagliptin, minoxidil and himplasia. Hence the present work has been aimed to find out the interaction with among the above said drugs in rodent model, since such studies cannot be performed in humans. Methods: Studies were conducted in normal and alloxan induced diabetic rats with oral doses of 9mg/kg B.W of sitagliptin, 9mg/kg B.W of minoxidil and 54mg /k g of himplasia and their combinations with adequate washout periods in between the treatments. Blood samples were collected at regular time intervals in rats through retro orbital puncture. All the blood samples were analyzed for blood glucose by GOD/POD method in pharmacodynamic studies and the serum sitagliptin concentrations were estimated by UV Spectrophotometry. Serum insulin was estimated by chemiluminescence assay. Results: Sitagliptin showed hypoglycemic action in both normal and diabetic rats and the peak action was observed at 6 h. Hyperglycemia was observed with minoxidil at 1st hour, hypoglycemia was observed with himplasia at 4th hour and the combination of minoxidil and himplasia showed biphasic response in blood glucose levels. The same responses were observed even in combination with sitagliptin. The serum sitagliptin concentrations were not altered by the co-administration of drugs. Serum insulin levels were inhibited by administration of minoxidil and potentiated by himplasia and initial reduction followed by surge observed with combination of minoxidil and himplasia. The similar responses were observed when co-administered with sitagliptin. Conclusion: Thus it could be concluded that the combination of minoxidil and himplasia should be taken with care for clinical benefits in diabetic patients. However, further studies should be carried out in non rodent species and in clinical settings are warranted.