Image: AI-generated editorial illustration of medicines in a research setting; not a depiction of a specific treatment or product.
A medicine developed for one condition can sometimes become useful for another. Diabetes medicines now help protect the heart and kidneys in selected patients. A blood-pressure medicine became a treatment for pattern hair loss. These are examples of drug repurposing, also called drug repositioning.
The important question is not simply whether a medicine has another possible use. It is whether reliable human studies show a worthwhile benefit, for which patients, and with what risks.
Repurposing and off-label prescribing are different
Repurposing means investigating or developing a new therapeutic use for an existing medicine or drug candidate. Sometimes that work leads to a new regulatory approval. Sometimes clinicians use the medicine off-label. Other ideas remain experimental.
Off-label use means prescribing an approved medicine outside its approved labeling, such as for a different condition, age group, route or regimen. In the United States, clinicians generally may prescribe approved medicines off-label when they judge it medically appropriate. That does not mean the FDA has endorsed or established safety and effectiveness for the unapproved use. FDA explanation of off-label use
A clinical trial registration, laboratory result or promising headline is not an approval. Equally, an established off-label use is not automatically ineffective. The quality of evidence and the individual patient’s situation matter.
A representative comparison of medicines and their newer uses
This is an educational selection, not a list of every repurposed medicine or a recommendation to take these drugs. The table combines well-established examples with newer extensions of use. Unless marked UK, regulatory statements refer to the United States. Approval is specific to the product, formulation, condition and eligible population, not automatically to every medicine in the same class.
On a smaller screen, swipe or scroll sideways within the table to see every column.
| Medicine | Original or familiar use | Repurposed or expanded use | Evidence and regulatory status | Important caution |
|---|---|---|---|---|
| Metformin | Blood-glucose control in type 2 diabetes | Modest weight reduction in selected patients; diabetes prevention in some high-risk people | Human trials support modest average weight effects. Weight-loss prescribing is off-label in the US; metformin is not an FDA-approved obesity medicine. Metformin label; DPP evidence | Digestive side effects and vitamin B12 deficiency can occur. Kidney function and lactic-acidosis risk require assessment. |
| Empagliflozin and dapagliflozin (SGLT2 inhibitors) | Type 2 diabetes | Heart failure and chronic kidney disease, including eligible patients without diabetes | Large outcome trials underpin approved US indications for specific products, including Jardiance and Farxiga. These benefits are not limited to lowering glucose. Jardiance label; Farxiga label | Risks include dehydration, genital infections and ketoacidosis, sometimes without very high glucose. Kidney status, illness and surgery affect treatment planning. |
| Semaglutide (a GLP-1 receptor agonist) | Type 2 diabetes, with products such as Ozempic | Long-term weight management; cardiovascular risk reduction in specified patients | Wegovy has US-approved weight-management indications and its injection has an indication to reduce major cardiovascular events in adults with established cardiovascular disease and overweight or obesity. This does not make every semaglutide product approved for weight loss. Wegovy label | Gastrointestinal effects, gallbladder disease and pancreatitis warnings matter. Contraindicated with a personal/family history of medullary thyroid carcinoma or MEN2. Not a cosmetic shortcut. |
| Minoxidil | Oral treatment for severe hypertension | Pattern hair loss | Topical formulations have approved hair-regrowth uses. Oral minoxidil for hair loss is off-label, with a different risk profile. FDA topical product record; NHS oral minoxidil information | Oral treatment can cause low blood pressure, rapid heart rate and fluid retention. Do not substitute oral tablets for scalp products. |
| Sildenafil | Familiar as an erectile-dysfunction treatment | Pulmonary arterial hypertension, a specific form of high pressure in lung arteries | Sildenafil products have approved US indications for erectile dysfunction and, in appropriate formulations such as Revatio, pulmonary arterial hypertension. These are different prescribing contexts. Revatio label | Must not be combined with nitrates or riociguat because of dangerous blood-pressure effects. Pulmonary hypertension requires specialist classification and care. |
| Duloxetine | Depression and anxiety | Diabetic nerve pain, fibromyalgia and chronic musculoskeletal pain | These are approved US indications, supported by clinical trials. An antidepressant can act on pain pathways without pain being imaginary or caused by depression. Duloxetine label | Important risks include serotonin syndrome, liver injury and withdrawal symptoms if stopped abruptly. Mood and suicidal-thought warnings also require attention. |
| Colchicine | Gout and other inflammatory conditions | Reducing cardiovascular events in selected adults | Lodoco has a US-approved cardiovascular indication for adults with established atherosclerotic disease or multiple cardiovascular risk factors. Evidence includes outcome trials; this is not a blanket recommendation for everyone. Lodoco label | Serious, potentially fatal toxicity can occur with certain interacting medicines. Kidney, liver and blood disorders affect suitability. It does not replace established cardiovascular care. |
| Propranolol | Hypertension and other cardiovascular uses | Selected infantile haemangiomas, benign blood-vessel growths that may threaten function or cause complications | Hemangeol oral solution is FDA-approved for proliferating infantile haemangioma requiring systemic therapy. Not every birthmark needs treatment. Hemangeol label | Specialist care is essential. Low blood sugar, slow heart rate, low blood pressure and bronchospasm are important risks. |
| Amitriptyline | Depression | Neuropathic pain and prevention of migraine or chronic tension-type headache | Established clinical uses. UK product labeling includes these adult indications; authorization elsewhere must be checked rather than assumed. UK product information; NHS overview | Sleepiness, dry mouth, constipation and heart-rhythm effects may limit use. Interactions and safe storage are important. |
Metformin for weight loss: what the evidence actually says
Metformin can produce modest weight loss, but it does not work equally well for everyone. In the Diabetes Prevention Program, participants assigned to metformin lost an average of about 2.1 kg during the trial. These were adults at high risk of diabetes, not a general population seeking rapid weight loss. An average is not a promised result. Original DPP/DPPOS weight analysis
A clinician may consider metformin when there is a relevant metabolic reason, including selected high-risk patients being treated to prevent or delay diabetes. That is different from recommending it for anyone who wants to lose weight. It is not a substitute for established obesity care, which may include nutritional and behavioural support, approved weight-management medicines, or metabolic surgery when appropriate. NIDDK diabetes-prevention guidance; NIDDK weight-management medicines
What makes a new use convincing?
Look beyond the phrase “promising research.” Evidence is stronger when well-designed human trials show meaningful improvements, such as fewer hospitalizations or better function, with an acceptable balance of harms. Small studies and laboratory experiments can generate useful hypotheses, but cannot establish that a treatment works in everyday care.
Ask whether the study included people like you, whether the benefit was compared with placebo or standard treatment, and whether independent studies support the finding. For emerging uses, uncertainty should be explicit. A familiar medicine is not automatically safe in a different population or combination.
What patients in India should check
US FDA approval or UK authorization does not establish approval in India. Ask a registered clinician or pharmacist to check the exact product’s current Indian labeling and applicable CDSCO authorization. Availability in a pharmacy, or an overseas brand’s approval, is not proof of approval for a particular use in India.
Before considering a repurposed medicine, ask:
- Is this use approved locally or off-label, and why is it suitable for me?
- What benefit is realistic, and how does it compare with established options?
- Which interactions, existing conditions or pregnancy considerations matter?
- What monitoring and follow-up will be needed?
Repurposing is a valuable route to better treatment when evidence supports it. It is not permission to self-prescribe. Do not start, stop, combine or substitute medicines on the basis of this table. It omits dosing intentionally and cannot replace an individual clinical assessment.
Sources and further reading
- FDA: Understanding off-label use
- NIDDK: Diabetes Prevention Program
- DPP Research Group: Long-term safety, tolerability and weight loss with metformin
- NIDDK: Prescription medicines for overweight and obesity
- Product-specific prescribing information and NHS resources are linked beside each table entry. Regulatory information checked 7 November 2026; indications can change.
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