Acetazolamide in Persons With Type 1 Diabetes - Crossover Trial

A Randomized, Double-blind, Placebo-Controlled, Crossover Trial (RCT) to explore the effects of 250mg acetazolamide in individuals with type 1 diabetes. Participants will be randomized to Treatment Group A or Treatment Group B. Randomization will be blinded, but one of these treatment groups will receive 250mg (milligram) BID (twice daily) of acetazolamide for 10 weeks - receive no study drug for 2 weeks - then receive placebo for 10 weeks; the other will receive placebo for 10 weeks - receive no study drug for 2 weeks - then receive 250mg BID of acetazolamide for 10 weeks. Both participants and study staff will be blinded to the study treatment group with only the research pharmacy staff being unblinded. To measure mGFR (measured glomerular filtration rate), an Iohexol GFR (glomerular filtration rate) procedure will be completed at the beginning and end of each treatment period. A standard protocol for the procedure will be followed that has been used in multiple studies. Iohexol (Omnipaque 300®) will be used in order to obtain a precise measure of mGRF throughout the course of the test. Iohexol will be prepared by the UCSD (University of California, San Diego) Investigational Drug Services at the ACTRI (Altman Clinical and Translation Research Institute) by drawing up 5mL into a syringe per standard pharmacy protocol. The iohexol will be dispensed to a nurse or research coordinator who will weigh the syringe prior to infusion and again after infusion to assess exact dosage delivered. A study nurse will insert 1 IV (intravenous) line in the hand or arm for the infusion of iohexol. They will then insert a second IV in the opposite arm for blood collection. Serial blood draws will occur throughout the procedure relative to the time of iohexol infusion. A study nurse will infuse iohexol over a 1-2 minute period, flush with 10mL (milliliter) of normal saline and remove the IV. Blood samples will be collected at the following time points for mGFR analysis: * -5 minutes (prior to iohexol infusion) * 2 hours (120 minutes post infusion) * 4 hours (120 minutes post infusion) * 6 hours (120 minutes post infusion)