Cimetidine and Metformin: Drug Interaction Guide

Quick answer: This combination requires caution. Cimetidine and Metformin can be used together with adjustments and monitoring.

Interaction severity: Moderate — caution required

How Cimetidine interacts with Metformin

Cimetidine competes with metformin for renal tubular secretion via the OCT2 transporter, reducing metformin clearance and increasing plasma levels by approximately 40%.

What you should do

Consider an alternative H2-antagonist such as famotidine. If cimetidine is required, monitor renal function and for symptoms of lactic acidosis.

Key facts

Severity

Moderate — caution required

Mechanism

Cimetidine competes with metformin for renal tubular secretion via the OCT2 transporter, reducing metformin clearance an...

Action

Consider an alternative H2-antagonist such as famotidine. If cimetidine is required, monitor renal function and for symp...

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Cimetidine and Metformin together?

With caution. Consider an alternative H2-antagonist such as famotidine. If cimetidine is required, monitor renal function and for symptoms of lactic acidosis.

What is the severity of this interaction?

The interaction between Cimetidine and Metformin is classified as Moderate — caution required. Cimetidine competes with metformin for renal tubular secretion via the OCT2 transporter, reducing metformin clearance and increasing plasma levels by approximately 40%.

What should I do if I'm prescribed both?

Consider an alternative H2-antagonist such as famotidine. If cimetidine is required, monitor renal function and for symptoms of lactic acidosis. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.