At what time should a patient who is taking isophane insulin suspension (NPH, Humulin N) eat a snack?

The correct time for a patient taking isophane insulin suspension (NPH, Humulin N) to eat a snack is in the mid-afternoon. This is because NPH insulin is an intermediate-acting insulin that typically reaches its peak effect between 4 to 12 hours after administration.

In the context of managing blood glucose levels, it is important for the patient to have a snack during the peak times of this insulin to help prevent hypoglycemia, which can occur when the insulin lowers the glucose levels in the bloodstream. Eating a snack in the mid-afternoon corresponds well with the predicted peak action of NPH and can provide the necessary carbohydrates to maintain stable blood sugar levels.

Other options might suggest eating before or immediately after the insulin administration, which does not align with the time frame when the risk of hypoglycemia is greatest. Additionally, the suggestion to eat every two hours during the daytime may be excessive and not practical for most patients, as it could lead to constant overconsumption of food. Therefore, the mid-afternoon snack is the most appropriate recommendation to align with the insulin's action and ensure blood glucose stability.