Drug Interactions With NPH Insulin

Oral diabetes medications, sulfa drugs, and ACE inhibitors may cause potentially dangerous drug interactions with NPH insulin. When combined with NPH insulin, these medicines could cause low blood sugar that can become life-threatening quite quickly. To help reduce your risk of developing NPH insulin drug interactions, you should check with your healthcare provider every time you start, stop, or change the dose of any medication.

 

An Overview of Drug Interactions With NPH Insulin

There are a number of different NPH
 insulin (Humulin® N, Novolin® N) drug interactions, too many to list entirely in this article. Interactions that may increase blood sugar levels are not discussed in this article, since high blood sugar is unhealthy but usually not dangerous right away (although extremely high blood sugar can become quite serious if left untreated). This article focuses on NPH insulin drug interactions that can result in dangerously low blood sugar levels (hypoglycemia), which can become life-threatening quite quickly. Some of the medicines that may cause dangerously low blood sugar levels when combined with NPH insulin include (but are not limited to):
 
  • ACE inhibitors (angiotensin-converting enzyme inhibitors), such as:

 

 

  • Beta blocker medications, including (but not limited to):

 

 

  • Disopyramide (Norpace®, Norpace® CR)
  • Fibrates, such as:

 

 

  • Monoamine oxidase inhibitors (MAOIs), such as:

 

 

  • Octreotide (Sandostatin®)
  • Oral diabetes medications
  • Propoxyphene (Darvon®, Darvocet®)
  • Reserpine
  • Salicylates, such as:

 

    • Aspirin (Ecotrin®, Bayer®, Anacin®)
    • Choline magnesium trisalicylate (Trilisate®)
    • Diflunisal (Dolobid®)
    • Salsalate (Salflex®, Disalcid®, Amigesic®)

 

  • Sulfonamides ("sulfa drugs"), such as:

 

    • Sulfadiazine
    • Sulfadoxine (Fansidar®)
    • Sulfamethoxazole (Bactrim®, Septra®)
    • Sulfisoxazole (Gantrisin®).

 

(Drug Interactions With NPH Insulin Continued: Page 2)
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;