This information is for educational purposes only. Off-label drug use carries risks. Always consult a qualified physician before using any drug outside its approved indication.
Metformin
Metformin Hydrochloride
Brand names: Glucophage, Glumetza, Fortamet
ORIGINALLY APPROVED FOR
Type 2 Diabetes
Metformin is the world's most prescribed diabetes drug and the most studied repurposed drug in oncology. It activates AMPK, which inhibits mTOR — the master regulator of cell growth and metabolism. Epidemiological studies consistently show diabetic patients on metformin have 20–40% lower cancer incidence and better survival outcomes. Over 100 clinical trials are currently investigating its role in cancer prevention and treatment.
Molecular Pathways Targeted
Mechanism of Action in Cancer
Inhibits mitochondrial complex I → reduces ATP → activates AMPK → suppresses mTOR signalling → slows cancer cell proliferation. Also reduces circulating insulin and IGF-1, which are tumour-promoting hormones. May selectively kill cancer stem cells.
Cancers Studied
Typical Off-Label Dosing
500–2000 mg daily (standard diabetes dosing). Some protocols use 1000–1500 mg. Must be taken with food to reduce GI side effects. Not suitable for non-diabetics without physician supervision.
* Dosing information from research literature only. Not a prescription. Requires physician supervision.
Cautions & Drug Interactions
- Not recommended in severe kidney impairment (eGFR < 30)
- Risk of lactic acidosis — rare but serious
- Avoid before contrast dye procedures — hold 48 hours
- Can cause GI upset, nausea, diarrhoea — start low and titrate
- Depletes B12 over time — monitor levels annually
- Only use off-label under physician supervision