Ask Joslin: How Should I Time My Meals and My Type 2 Diabetes Medications?

People with type 2 diabetes may take up to three or four oral medications, insulin or an incretin to control their blood glucose levels.  Oral medications usually work through different pathways in the body and attack high glucose levels from different angles.  How and when you take them can mean getting that extra edge in your control as well as avoiding or reducing the unpleasant side  effects of some of these medications.

Let’s start with the ubiquitously prescribed drug called metformin, brand name Glucophage®.  Metformin works by reducing the amount of glucose produced by your liver but it comes with a nasty, (although usually short-lived) side effect of stomach upset, gas and diarrhea.  However, taking it with meals often blunts the intensity of the gastrointestinal symptoms (GI).  Usually the full dose of metformin is given at breakfast and dinner.  However, if you don’t have any GI symptoms, and you have elevated glucose levels in the morning, your health care provider may suggest that take you medication later in the evening to reduce your morning numbers.

Sulfonylureas are the old workhorse of diabetes oral medications.  They stimulate the beta cells in the pancreas to make more insulin.  There are two generations of sulfonylureas, but the older versions are rarely used anymore.  Although there are many brand names for the second generation formulary including, Diabeta®, Micronase®, Glynase® and Glucotrol®, it is divided into two main drugs, glyburide and glipizide.   For best effect take Diabeta®, Micronase® and Gynase® right before you eat.  Glucotrol® should be ideally taken one-half hour before meals.  Most often you will be taking sulfonylureas once or twice a day.

Starlix® and Prandin®, which work in a similar manner to the sulfonylureas, are usually given with each meal.  You can take these up to 30 minutes before a meal.  If you don’t plan to eat a meal or don’t plan to eat anything with carbohydrate, you should skip your dose because otherwise you could have a low blood glucose reaction.

Two categories of drugs, DPP-4 inhibitors, which prevent the breakdown of incretins so they stay around longer and increase insulin’s action time (brand names Januvia®, Onglyzia TM and Tradjenta TM) and the thiazolidinediones (TZDs) (brand names Actos® and Avandia®) do not cause low blood glucose levels and do not usually cause GI upset.  They can be taken with or without food.  Most often they are given once in the morning. The TZDs can take up to six weeks to fully work so don’t panic if you don’t see changes in your blood glucose levels right away.

People with diabetes often have many co-morbidies, such as high blood pressure and elevated cholesterol levels, for which they take additional oral medications.  Since some medications can interact with others, it is always best to check with your health care provider about the best time and sequence to take your medications.

Do you have a (non-medical) question you would like answered? Ask Joslin in the comments! Your question could be answered in a future blog, or in an upcoming video series. 


  1. Is there any facility for foreign visitors to go through a comprehensive testing over 3-4 or 7 days at the maximum? And having prescription medicines for a long period to take when they go back to their own countries.
    If yes, who to contact for appointments?

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