Pharmacology Diabetes meds #14

Question

The nurse instructs a patient with Type 2 diabetes on which of the adverse interactions between metformin and cimetidine?

Answers

  1. Taking metformin with cimetidine will result in increase in metformin levels and risk of hypoglycemia
    • Rationale:

      This answer is correct because if given with the over-the-counter H2 antagonist, cimetidine, blood levels of metformin can increase, causing a risk of hypoglycemia. Patients should be taught to avoid combining these two medications due to this risk. Other over-the-counter medications for gastroesophageal reflux disease, such as proton pump inhibitors, could be considered since those medications are effective against the gastrointestinal symptoms associated with metformin.

  2. Taking metformin with cimetidine will result in decrease levels of metformin and risk of hyperglycemia
    • Rationale:

      This answer is not correct because if given with the over-the-counter H2 antagonist, cimetidine, blood levels of metformin can increase (not decrease), causing a risk of hypoglycemia (not hyperglycemia).

  3. Taking metformin with cimetidine will result in lowered low-density lipoprotein.
    • Rationale:

      This answer is not correct because cimetidine, a H-2 inhibitor, does not decrease low-density lipoprotein levels when combined with metformin, an oral anti-diabetic. Metformin is known to decrease low-density lipoprotein levels by itself.

  4. Taking metformin with cimetidine will result in higher levels of lipid production.
    • Rationale:

      This answer is not correct because cimetidine, a H-2 inhibitor, does not increase low-density lipoprotein levels when combined with metformin, an oral anti-diabetic. Metformin is known to decrease (not increase) low-density lipoprotein levels by itself.

Overview

Cimetidine, an over-the-counter H2 antagonist, increases the effects of metformin and can cause increased risk of hypoglycemia if given together.

Explanation

Taking metformin with cimetidine may result in higher levels of metformin, thus possible risk of hypoglycemia. This is important since cimetidine is over-the-counter. The other selections are not true of metformin and cimetidine.

Learning Outcomes

Metformin is a prescription oral antidiabetic medication prescribed for the treatment of diabetes mellitus type 2. If given with the over-the-counter H2 antagonist, cimetidine, blood levels of metformin can increase, causing a risk of hypoglycemia. Patients should be taught to avoid combining these two medications due to this risk. Other over-the-counter medications for gastroesophageal reflux disease, such as proton pump inhibitors, could be considered since those medications are effective against the gastrointestinal symptoms associated with metformin.

Test Taking Tip

Metformin should be stopped 48 hours before surgery and 48 hours after surgery to help decrease the risk of lactic acidosis.

Video Rationale