Does Metformin Interact with Propranolol?
Metformin and Propranolol have a unknown drug interaction according to U.S. FDA drug labeling data. Warn patients against excessive alcohol intake ( 7 ) Drug Interactions In Vivo Assessment of Drug Interactions Table 5: Effect of Coadministered Drug on Plasma Metformin Systemic Exposure Coadministered Drug Dose of Coadministered Drug All metformin hydrochloride and coadministered drugs were given as single doses Dose of Metformin Hydrochloride Geometric Mean Ratio (ratio with/without coadministered drug) No Effect = 1.00 AUC AUC = AUC inf C max No dosing adjustments required for the following: Glyburide 5 mg 850 mg metformin 0.91 Ratio of arithmetic means 0.93 Furosemide 40 mg 850 mg metformin 1.09 1.22 Nifedipine 10 mg 850 mg metformin 1.16 1.21 Propranolol 40 mg 850 mg metformin 0.90 0.94 Ibuprofen 400 mg 850 mg metformin 1.05 1.07 Cationic drugs eliminated by renal tubular secretion may reduce metformin elimination [ See Warnings and Precautions (5.1) and Drug Interactions (7) . ] Cimetidine 400 mg 850 mg metformin 1.40 1.61 Carbonic anhydrase inhibitors may cause metabolic acidosis [ See Warnings and Precautions (5.1) and Drug Interactions (7) .] Topiramate 5 mg At steady state with topiramate 100 mg every 12 hours and metformin 500 mg every 12 hours; AUC = AUC 0-12h 5 mg metformin 1.25 1.17 Table 6: Effect of Metformin on Coadministered Drug Systemic Exposure Coadministered Drug Dose of Coadministered Drug All metformin hydrochloride and coadministered drugs were given as single doses Dose of Metformin Hydrochloride Geometric Mean Ratio (ratio with/without metformin) No Effect = 1.00 AUC AUC = AUC inf unless otherwise noted C max No dosing adjustments required for the following: Glyburide 5 mg 850 mg glyburide 0.78 Ratio of arithmetic means, p-value of difference < 0.05 0.63 Furosemide 40 mg 850 mg furosemide 0.87 0.69 Nifedipine 10 mg 850 mg nifedipine 1.10 AUC 0-24hr reported 1.08 Propranolol 40 mg 850 mg propranolol 1.01 1.02 Ibuprofen 400 mg 850 mg ibuprofen 0.97 Ratio of arithmetic means 1.01 Cimetidine 400 mg 850 mg cimetidine 0.95 1.01 Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Unknown
- Management
- Consult your pharmacist
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Metformin and your doctor is considering prescribing Propranolol (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Never stop or change either medication without first consulting your healthcare provider