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What the FDA labels say about taking them together

Metformin and ranolazine

Metformin's FDA label of September 3, 2026 names ranolazine in its drug interactions section, and ranolazine's label names metformin too. The metformin label: “Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin could increase systemic exposure to metformin and may increase the risk for lactic …”

Check it at the source: the metformin FDA label on DailyMed (effective September 3, 2026, Granules India Ltd); the ranolazine FDA label on DailyMed (effective January 23, 2026, Glenmark Pharmaceuticals Inc., USA).

What does the metformin label say about ranolazine?

Metformin label, drug interactions

Drugs that Reduce Metformin Hydrochloride Extended-Release Tablets Clearance Clinical Impact: Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (…) could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Intervention: Consider the benefits and risks of concomitant use with metformin hydrochloride extended-release tablets. Examples: Ranolazine, vandetanib, dolutegravir, and cimetidine.

Riomet label (Sun Pharmaceutical Industries, Inc., December 6, 2018), drug interactions

1. Examples:; 1. Ranolazine, vandetanib, dolutegravir, and cimetidine.

Source: FDA drug label (Riomet, NDA021591), Sun Pharmaceutical Industries, Inc., effective December 6, 2018 (SPL set 05d4df4b-dfe8-4828-b423-a3d4f2c4114a), via openFDA

Source: FDA drug label (METFORMIN HYDROCHLORIDE), Granules India Ltd, effective September 3, 2026 (SPL set 73197cb5-3e23-4ac0-b189-f9bc848bce66), via openFDA; the full label on DailyMed

What does the ranolazine label say about metformin?

Ranolazine label, drug interactions

Drugs Transported by OCT2 In subjects with type 2 diabetes mellitus, concomitant use of ranolazine extended-release tablets 1000 mg twice daily and metformin results in increased plasma levels of metformin.

Source: FDA drug label (Aspruzyo Sprinkle, NDA216018), SUN PHARMACEUTICAL INDUSTRIES, INC., effective January 29, 2025 (SPL set dd9f81e4-50da-4551-aed5-559d304df42e), via openFDA

Source: FDA drug label (Ranolazine), Glenmark Pharmaceuticals Inc., USA, effective January 23, 2026 (SPL set 0cf58732-c242-49b0-8e3f-248778b4458d), via openFDA; the full label on DailyMed

These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.

Both medicines on the record

80Metformin generic labelers
28Ranolazine generic labelers
MetforminRanolazine
Labeled forType 2 diabetesAngina
Boxed warningYesNo
Pharmacy cost (NADAC)$0.0145 per tablet 500 mg tablet$0.165 per tablet 500 mg tablet
Shortage nowNo current entryNo current entry

Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)

What next?