From the Guidelines
Bactrim (sulfamethoxazole-trimethoprim) and glipizide can be used together, but caution is advised due to potential interactions that may increase the risk of hypoglycemia, as noted in the most recent guidelines 1. When taking these medications concurrently, blood glucose levels should be monitored more frequently as Bactrim may enhance the blood glucose-lowering effect of glipizide, potentially causing hypoglycemia. Some key points to consider when using these medications together include:
- Monitoring for signs of low blood sugar such as dizziness, confusion, sweating, or shakiness, and reporting these symptoms to the healthcare provider immediately
- Potential need for dosage adjustments of glipizide during and after Bactrim treatment
- Importance of adequate hydration, as both medications can potentially cause kidney problems
- Need for closer monitoring or dosage adjustments in patients with reduced kidney function
- Informing all healthcare providers about all medications being taken to prevent potential drug interactions, as emphasized in recent standards of care 1. It is crucial to be aware of the potential interaction between sulfonylureas, such as glipizide, and antimicrobials like Bactrim, which can increase the effective sulfonylurea dose and precipitate hypoglycemia 1.
From the FDA Drug Label
Like other sulfonamide-containing drugs, sulfamethoxazole and trimethoprim potentiates the effect of oral hypoglycemic that are metabolized by CYP2C8 (e.g., pioglitazone, repaglinide, and rosiglitazone) or CYP2C9 (e.g., glipizide and glyburide) or eliminated renally via OCT2 (e.g., metformin). Additional monitoring of blood glucose may be warranted.
The interaction between Bactrim (trimethoprim/sulfamethoxazole) and glipizide is that Bactrim may potentiate the effect of glipizide, which is an oral hypoglycemic metabolized by CYP2C9. Therefore, additional monitoring of blood glucose is recommended when co-administering these drugs to avoid hypoglycemia 2.
From the Research
Interaction between Bactrim and Glipizide
- The interaction between Bactrim (trimethoprim/sulfamethoxazole) and glipizide can lead to an increased risk of hypoglycemia, as reported in a case study where an 83-year-old man developed symptomatic hypoglycemia within three days of adding trimethoprim/sulfamethoxazole to his glipizide regimen 3.
- The mechanism of this interaction is likely due to the inhibition of glipizide metabolism by trimethoprim/sulfamethoxazole, rather than protein-binding displacement 3.
- Another study found that coadministration of co-trimoxazole with sulfonylureas, including glipizide, increased the risk of hypoglycemia-related emergency room visits in older adults with diabetes 4.
- Trimethoprim/sulfamethoxazole can also cause hypoglycemia on its own, particularly in patients with risk factors such as compromised renal function, prolonged fasting conditions, malnutrition, and excessive doses 5.
- While there is no direct evidence on the cost-effectiveness of combining glipizide with other medications, a review highlights the safety and efficacy of affordable combination therapies, including glipizide + metformin, in the management of type 2 diabetes mellitus 6.
Risk Factors and Precautions
- Patients at high risk for hypoglycemia, such as the elderly and those with renal dysfunction, should be closely monitored when taking glipizide and trimethoprim/sulfamethoxazole concurrently 3, 4.
- Healthcare providers should be aware of the potential interaction between trimethoprim/sulfamethoxazole and glipizide, and adjust treatment regimens accordingly to minimize the risk of hypoglycemia 3, 4.
- Patients with identifiable primary care physicians may have lower odds of receiving a co-trimoxazole prescription, highlighting the importance of coordinated care in preventing potential drug interactions 4.