Tag: Healthy Ageing

Taking Metformin for Years? What Older Adults With Diabetes Should Know in 2026

Metformin remains an important treatment for type 2 diabetes, but long-term use deserves monitoring. Here is what older adults should know about vitamin B12, kidney function, stomach problems and medication safety in 2026.

Metformin is one of those medicines that can quietly become part of everyday life.

A tablet after breakfast. Another with dinner. Months turn into years. If blood sugar remains reasonably controlled, it is easy to stop thinking about the medicine itself.

That may be a mistake, particularly as we grow older.

Metformin remains an important and widely used treatment for type 2 diabetes. Doctors have decades of experience with it, and when used on its own it has a relatively low risk of causing hypoglycaemia. The American Diabetes Association’s 2026 guidance for older adults continues to describe metformin as a useful glucose-lowering option for many older people.

But long experience with a medicine does not mean we should stop monitoring it. For somebody who has taken metformin for years, the better question is not simply, “Is metformin safe?” It is: What should my doctor and I continue checking as I get older?

The First Thing I Would Check: Vitamin B12

Metformin can reduce vitamin B12 levels. This is not merely a theoretical association. A long-term randomized trial published in The BMJ found lower B12 concentrations and a greater risk of biochemical B12 deficiency among people receiving metformin.

The problem is particularly relevant because B12 deficiency can be easy to overlook. Tiredness may be blamed on age. Tingling or numbness may be attributed to diabetic neuropathy. Weakness can have many explanations. Anaemia may develop gradually.

I have written separately about vitamin B12 deficiency in ageing, including why neurological symptoms and medication-related risk deserve attention. For long-term metformin users, that connection is especially important.

The 2026 ADA guidance for older adults recommends annual B12 monitoring in older adults who have been taking metformin for more than four years. The UK’s Medicines and Healthcare products Regulatory Agency also advises testing when deficiency is suspected and considering periodic monitoring in people with risk factors.

Finding low B12 does not automatically mean a patient should stop metformin. The deficiency can usually be investigated and treated while the diabetes regimen is reviewed separately by the treating clinician.

Kidney Function Matters More as We Age

Metformin leaves the body largely through the kidneys. That makes kidney function an important part of safe prescribing.

Doctors commonly assess kidney function using estimated glomerular filtration rate, or eGFR. According to the 2026 ADA guidance for older adults, metformin can generally be used when eGFR is 30 mL/min/1.73 m² or higher, with lower dosing appropriate when eGFR is between 30 and 45. Metformin should not be used below the recommended kidney-function threshold.

This does not mean everyone approaching an eGFR of 45 must suddenly stop taking it. It means the prescription needs more careful assessment. Kidney function can change with age and illness. A dose that was appropriate years ago may need reconsideration later.

The Rare Risk That Gets the Most Attention

Lactic acidosis is probably the metformin complication that frightens patients most when they read about it online. It is serious. It is also rare.

The useful question is therefore not whether the risk exists, but when that risk becomes more important. Advanced kidney impairment is one concern. Severe illness involving hypoxia or poor tissue perfusion can also change the risk assessment.

A clinician may temporarily stop metformin during a serious acute illness, hospitalization or in connection with certain procedures involving iodinated contrast. That does not necessarily mean the medicine has suddenly become dangerous. The patient’s circumstances have changed. Once the acute problem resolves and kidney function is satisfactory, the clinician can decide whether treatment should be restarted.

Diarrhoea and Stomach Problems Are Much More Common

For most people, the problem they are more likely to encounter is far less dramatic. The stomach complains.

Diarrhoea, nausea, abdominal discomfort and bloating are well-established adverse effects of metformin. Many people tolerate it perfectly well, while symptoms can be more noticeable when treatment begins or the dose increases.

Slow dose escalation can help. Extended-release metformin is another option doctors may consider when gastrointestinal tolerance becomes difficult. It would be too simplistic, however, to promise that changing formulations will eliminate every symptom.

Persistent diarrhoea should not simply be tolerated for months because “metformin always does this.” It deserves discussion with a doctor. There may be another cause, or the dose or formulation may need reconsideration.

Appetite Deserves Attention in Older Adults

Metformin can reduce appetite. For an overweight younger adult, modest appetite reduction may not sound concerning. The calculation can change in an older person who is already losing weight, eating poorly or becoming frail.

Unintentional weight loss in later life should not automatically be celebrated simply because someone has diabetes. Muscle mass matters. Nutrition matters. The ADA notes that appetite reduction from metformin can become problematic in some older adults.

This is a good example of why diabetes treatment cannot be reduced to one glucose number. Treatment has to fit the person.

What About Hypoglycaemia?

Metformin has an important advantage here. When taken by itself, it carries a low risk of hypoglycaemia.

Many people with type 2 diabetes do not take metformin alone. They may also use insulin or another glucose-lowering medicine. In that situation, a low glucose reading cannot automatically be blamed on metformin. The entire medication regimen needs to be examined.

What I Would Remove From My 2023 Article

Looking back at older health writing is useful because medical evidence forces a writer to be humble.

Some claims in my 2023 discussion of metformin were too broad. I mentioned anxiety, depression and muscular pain among possible long-term problems without giving readers enough evidence or context. I would not present those today as established routine long-term adverse effects of metformin.

That does not mean a person experiencing muscle pain, mood changes or other unexplained symptoms should ignore them. It means we should not automatically attribute such symptoms to metformin without evidence.

Five Conversations Worth Having With Your Doctor

If you have been taking metformin for years, you do not need to become frightened of the medicine. You need better questions.

  • When was my kidney function last checked, and what is my eGFR?
  • If I have used metformin for several years, should my vitamin B12 be measured?
  • Could persistent diarrhoea, nausea or loss of appetite be related to my treatment?
  • What should I do with metformin if I become seriously ill, dehydrated or am admitted to hospital?
  • Is my current dose and overall diabetes regimen still appropriate for me now?

That last question becomes more useful with age. A prescription should not remain unchanged merely because it has remained unchanged for years.

Metformin Is Not the Enemy

Updating this article has changed the way I would frame the subject. The interesting story is not that metformin has frightening hidden dangers. It doesn’t need that headline.

The more useful story is that a familiar medicine still deserves attention after years of use. For many older adults with type 2 diabetes, metformin remains useful. Its low risk of hypoglycaemia is valuable. Decades of clinical experience also mean doctors understand its benefits and limitations unusually well.

But ageing changes the patient even when the medicine remains the same. Kidney function can decline. Nutrition can change. Other medicines accumulate on the prescription. B12 levels may fall quietly.

Do not stop metformin because you are worried about its long-term effects. Make sure its long-term effects are actually being monitored.

Medical note: This article is for general health education and does not replace individual medical advice. Do not start, stop or change prescribed medication without consulting an appropriate healthcare professional.

The Hidden Health Risk After 65 May Be Inside the Medicine Cabinet

A new 2026 JAMA study finds that more than one in five older Americans used medication combinations with potentially major drug interactions. Here is what the findings mean, what they do not prove, and why people over 60 should periodically review prescriptions, OTC medicines and supplements together.

I recently looked at the medicines an older person can accumulate without doing anything obviously reckless. There may be tablets for blood pressure in one place, diabetes medicines nearby, perhaps aspirin or another heart medicine. Then come the things we hardly think of as medicines: a painkiller bought without prescription, a vitamin, an herbal preparation.

Each may have a perfectly sensible reason for being there.

The trouble can begin with the combination.

A new study published in JAMA on September 24, 2026 provides an uncomfortable reminder of this problem. Researchers found that more than one in five older Americans in their latest survey period were using a medication regimen containing at least one potentially major drug-drug interaction.

That does not mean one in five suffered serious harm. The distinction matters.

It does mean that medicine cabinets deserve more attention as we grow older.

More medicines, but not necessarily more safety

Researchers led by Dima Mazen Qato of the University of Southern California examined nationally representative data from community-dwelling Americans aged 62 to 85. They compared 2,754 people surveyed in 2015–2016 with 2,186 surveyed in 2021–2023.

The results contain an interesting contradiction.

Prescription polypharmacy, defined in this study as taking five or more prescription medicines concurrently, increased from 31.0 percent to 35.7 percent.

Supplement polypharmacy also increased, from 12.6 percent to 16.7 percent.

Yet exposure to regimens containing potentially major drug interactions actually declined, from 25.7 percent to 22.3 percent.

So the story is not simply that older people are swallowing more tablets and medicine has become less safe. Prescribing appears to have improved in some areas. Even so, 22.3 percent remains a striking figure.

Roughly one in five people in this American sample was still exposed to a combination that researchers classified as potentially capable of causing a major interaction.

The word potentially needs to stay in that sentence.

The study identified interacting medication regimens. It did not establish that every person taking them experienced an adverse event. The researchers themselves list the absence of data on actual adverse drug events as an important limitation.

That restraint makes the findings more useful, not less.

The 63,000 reports that caught my attention

Another number in the JAMA paper deserves careful reading.

The researchers report that between 2015 and 2025, approximately 63,000 serious adverse events attributed to drug-drug interactions were reported to the US Food and Drug Administration among adults aged 65 and older. About 10 percent of those reports involved a fatal outcome.

It would be tempting to turn that into a frightening headline. I will not.

Spontaneous adverse-event reports are valuable for detecting safety signals, but a report does not by itself prove that a particular interaction caused the patient’s injury or death. Reporting systems can also contain incomplete information and are not designed to calculate the incidence of an event in the whole population.

Still, 63,000 serious reports tell us something important.

Medication interaction is not an obscure theoretical problem.

Which medicines appeared most often?

The JAMA researchers also examined the therapeutic classes appearing in potentially major interacting regimens.

In 2021–2023, antidepressants were the most common, appearing in such regimens among an estimated 7.21 percent of older adults. Statins followed at 5.23 percent, while antiplatelet therapies appeared at 4.47 percent.

Those figures should not be read as warnings to abandon antidepressants, statins or antiplatelet medicines.

Quite the opposite.

These drugs can provide substantial benefits when properly prescribed. A person at cardiovascular risk may have a strong clinical reason for taking a statin or antiplatelet drug. Someone with depression may genuinely need an antidepressant.

The problem is the combination, dose, patient’s condition and other medicines being taken.

One change in the study particularly caught my eye. Potentially interacting regimens involving opioid analgesics declined from 5.56 percent to 4.04 percent. Those involving benzodiazepines fell from 2.05 percent to 0.87 percent.

But interacting regimens involving muscle relaxants increased from 1.35 percent to 2.49 percent.

The authors argue that greater attention should now be paid to those combinations.

Medicine safety, in other words, is a moving target.

Age changes what a medicine does to us

There is another reason this becomes important after 60.

Our bodies do not process medicines exactly as they did when we were 30.

The US Food and Drug Administration points out that ageing can change how medicines work in the body. Kidney and liver function may decline, affecting how drugs are broken down or eliminated.

A dose tolerated for years may therefore deserve review later.

Some medication effects can also look like new diseases. The FDA specifically mentions symptoms such as dizziness, sleepiness and memory difficulties.

Imagine what can happen.

An older person becomes dizzy. Everyone assumes it is simply age. He becomes unusually sleepy, so the family worries about weakness. Memory seems poorer and dementia enters the conversation.

Sometimes the explanation may indeed be disease.

But sometimes the medication list deserves inspection.

The tablet bought without a prescription still counts

Here in Karachi, I think this is where the issue becomes especially practical.

People often distinguish between a doctor’s medicine and something they bought themselves. The body makes no such distinction.

A painkiller from the pharmacy remains pharmacologically active. So does an antihistamine. So does an herbal preparation.

Supplements deserve the same attention.

The FDA warns that dietary supplements can alter the absorption, metabolism or excretion of medicines. That can increase or reduce the amount of a drug effectively reaching the body.

Some combinations can increase bleeding risk.

Others can change how well a medicine works.

“Natural” tells us something about marketing or origin. It does not establish that a product cannot interact with prescription medicine.

That small distinction belongs on every older person’s medication list.

Polypharmacy is not automatically bad medicine

There is another trap here.

After reading about polypharmacy, someone may conclude that taking five medicines is inherently dangerous and decide to eliminate a few.

Please don’t.

For someone living with several chronic illnesses, multiple medicines may represent entirely appropriate treatment.

The question is not simply: How many tablets am I taking?

A better question is: Do I still need each one, at this dose, in this combination?

The World Health Organization’s work on medication safety and polypharmacy takes this person-centred approach. WHO stresses the importance of medication review while recognising that people with several long-term illnesses may legitimately need multiple treatments.

Britain’s National Institute for Health and Care Excellence makes a similar point. It recommends considering structured medication reviews for older people, those with chronic conditions and people taking multiple medicines.

The purpose is not a tablet-counting exercise.

It is to determine whether treatment still makes sense for that particular person.

Bring the whole medicine cabinet to the conversation

A useful medication review should include more than prescriptions.

Write down every regular medicine. Add medicines taken only occasionally.

Then include vitamins, herbal preparations and dietary supplements.

For each item, record the dose and why you take it.

The FDA recommends keeping an up-to-date medication list and sharing it with healthcare professionals. Keeping one pharmacy involved where practical can also help because a pharmacist may see combinations prescribed by different doctors.

There are several questions worth asking during a review.

  • Why am I still taking this medicine?
  • Is the dose still appropriate for my age and kidney or liver function?
  • Could any of these medicines interact?
  • Could one of them explain dizziness, sleepiness, stomach trouble or another new symptom?
  • Does an over-the-counter medicine or supplement change the picture?

One question may lead to another. That is fine. Medication review is supposed to be a clinical conversation, not an attempt to reach a predetermined number of tablets.

Most importantly, do not stop a prescribed medicine because an interaction checker, article or social-media post frightened you.

Potential interactions vary enormously in clinical importance. Doctors sometimes prescribe interacting medicines deliberately because the expected benefit outweighs the risk, with dose adjustment or monitoring where appropriate.

Pakistan has a system for reporting suspected reactions

Medication safety is not solely an American issue.

Pakistan’s Drug Regulatory Authority of Pakistan operates a National Pharmacovigilance Centre for monitoring suspected adverse reactions to medicines and other therapeutic goods.

DRAP says patients and consumers can report suspected side effects. Its guidance asks for information about the medicine involved, dose, timing, other medicines being taken and relevant medical conditions.

That last detail matters.

A suspected reaction cannot be understood properly if nobody knows what else the patient swallowed.

DRAP reported in its MedSafetyWeek material that its National Pharmacovigilance Centre had received and processed more than 30,000 reports since 2018. That figure covers suspected medicine-safety reports generally and should not be confused with the US interaction figures in the JAMA study.

Different system. Different population.

The principle, however, travels well: unexplained adverse effects deserve investigation and reporting rather than assumption.

The doctor may know every medicine and still miss the complete picture

Modern medicine has become increasingly specialised.

A cardiologist may manage the heart. Another physician manages diabetes. A different doctor treats pain or depression.

Each can prescribe rationally within a particular field.

The patient remains the only person standing at the intersection of all those prescriptions.

That is why medication reconciliation matters so much.

The danger does not require a careless doctor. It can emerge from a fragmented system in which each prescription makes sense separately while nobody has recently examined the entire combination.

Then the patient adds an OTC painkiller.

Perhaps a supplement enters the cupboard.

Nothing dramatic happens that evening. Months pass.

The risk remains invisible because the medicine cabinet looks ordinary.

My medicine cabinet now looks different to me

The new JAMA study does not tell older people to fear medicine.

I take almost the opposite lesson from it.

Modern medicines allow millions of people to control illnesses that once shortened lives much earlier. Blood-pressure treatment prevents strokes. Diabetes medicines reduce complications. Cardiovascular drugs save lives.

Ageing successfully may therefore require more medicine, not less.

But more medicine creates another responsibility.

Every so often, someone needs to look at the complete list.

Not only the cardiologist’s medicines. Not only the latest prescription. Not merely the tablets we personally consider important.

Everything.

The most useful health check after 60 may occasionally begin without a blood test or scan.

It may begin with a sheet of paper and a surprisingly simple question:

“Do I still need all of these, together?”

Medical note: This article provides general health information and does not replace individual medical advice. Never stop, start or change the dose of a prescribed medicine without consulting an appropriate healthcare professional.