Metformin/Pioglitazone and Cimetidine Interaction

Drug interaction information between Metformin/Pioglitazone and Cimetidine.

Metformin/Pioglitazone and Cimetidine have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Metformin/Pioglitazone and Cimetidine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.

Drug A

Metformin/Pioglitazone

Biguanide / TZD Combination

Drug B

Cimetidine

H2 Receptor Antagonist

How They Interact

Cimetidine makes it harder for your kidneys to clear metformin out of your blood. This causes the medicine to accumulate in your body, which can lead to a serious side effect called lactic acidosis.

FDA Label Information

( 7.3 ) Drugs that reduce metformin clearance (such as ranolazine, vandetanib, dolutegravir, and cimetidine), may increase the accumulation of metformin. 7.4 Drugs that Reduce Metformin Clearance Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE] inhibitors such as ranolazine, vandetanib, dolutegravir, and cimetidine) could increase systemic exposure to metformin and may increase the risk for lactic acidosis [see Clinical...

Frequently Asked Questions

What SPL severity band is on file for Metformin/Pioglitazone + Cimetidine?

Compiled FDA labeling labels this pair moderate. That is a source-record field, not an individual medication-combination decision.

Which drug in this pair has the larger labeled-interaction portfolio?

Cimetidine has 77 labeled pairs on file vs Metformin/Pioglitazone's 10. In the moderate band specifically: Metformin/Pioglitazone has 3 (also Dolutegravir, Ranolazine); Cimetidine has 10 (also Empagliflozin, Empagliflozin/Linagliptin, Ertugliflozin, Hydroxychloroquine).

What mechanism field is on file for Metformin/Pioglitazone and Cimetidine?

Cimetidine makes it harder for your kidneys to clear metformin out of your blood. This causes the medicine to accumulate in your body, which can lead to a serious side effect called lactic acidosis.

Cimetidine carries more major-labeled pairs than Metformin/Pioglitazone

SPL source-record counts only. This page's band is moderate · classes on file: Metformin/Pioglitazone (Biguanide / TZD Combination); Cimetidine (H2 Receptor Antagonist).

Cimetidine has 4 major-labeled pairs vs Metformin/Pioglitazone's 0. This page itself is in the moderate band, not the major band.

Metformin/Pioglitazone

0 major · 3 moderate · 7 minor · 10 total

Cimetidine

4 major · 10 moderate · 63 minor · 77 total

Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.