One of the most common misconceptions I encountered as a doctor was the belief that medicines and treatments are either safe or dangerous.
Patients would often ask, “Is it safe?”
It sounds like a simple question. But in medicine, the answer is more complicated than a simple ‘Yes’ or ‘No’.
Doctors don’t usually think in terms of safe versus unsafe. They think in terms of risk and benefit.
That’s because almost every treatment in medicine carries some degree of risk. The real question is whether the potential benefit outweighs potential harm.
This can be difficult for people to understand because we want certainty in answers. We tend to think in absolutes and assume treatments fit neatly into categories: good or bad, helpful or harmful, safe or dangerous.
Medicine doesn’t work that way.
Take chemotherapy. Many chemotherapy drugs are toxic enough that, if given to a healthy person, they could cause serious illness, particularly if they suppress bone marrow, increase infection risk, cause nausea and fatigue, and can damage nerves, kidneys, lungs or the heart.
Yet oncologists prescribe them every day.
Why? Because the risk posed by the cancer is often far greater than the risk posed by the treatment.
The question isn’t whether chemotherapy is safe. The question is whether it offers the best chance of controlling a potentially life-threatening disease.
The same principle applies to surgery.
Every operation carries a degree of risk – from the anaesthetic, bleeding, infection, blood clots and complications specific to the procedure itself. Then doctors need to consider the complicating factors of patient’s medical issues, medications, age and chances of recovery.
Yet people undergo surgery every day because the likely benefits outweigh those risks.
Even CPR, which many people view as a lifesaving intervention, is not without harm.
As I’ve written before, broken ribs, punctured lungs, damage to internal organs and significant neurological injury can occur. Anyone who has witnessed CPR in real life quickly realises it bears little resemblance to the version portrayed on television.
We do it because the alternative is often death.
Again, doctors aren’t asking whether CPR is safe. They’re asking whether the potential benefit justifies the risk.
Pregnancy provides yet another great example. Women often ask whether a medication is safe during pregnancy. Again, the answer is rarely yes or no.
Some medications carry potential risks to a developing baby. But untreated illness can also pose risks.
A woman with epilepsy may require medication throughout pregnancy because uncontrolled seizures may endanger both mother and baby.
A woman with severe depression may benefit from continuing antidepressants because untreated depression carries its own serious consequences.
In these situations, doctors aren’t choosing between safe or dangerous.
They’re choosing between different risks.
One of the most important lessons medical students learn is that doing nothing is also a decision. And doing nothing is not without risk.
More recently, drugs such as Ozempic have provided another useful example.
For some people with obesity or type 2 diabetes, these medications can be transformative. They can improve blood sugar control, reduce cardiovascular risk and help people achieve significant weight loss that may improve long-term health. Meanwhile, studies into prolonged use are ongoing.
That doesn’t automatically mean they are appropriate for everyone who just wants to lose a few kilograms.
Potential benefits and risks vary depending on the individual patient and the reason for treatment. Side effects may be life-affecting or even life-threatening because the same drug can have a completely different risk-benefit equation for each potential user.
Many people assume that if a drug is approved by the Pharmaceutical Benefits Scheme or prescribed by doctors, it must be broadly safe.
But approval doesn’t mean a drug is suitable for other conditions.
It means evidence has shown that its benefits outweigh its risks for a specific condition, in a particular group of patients.
This misunderstanding often surfaces whenever a medication approved for one condition is promoted as a treatment for something else.
The prominence of Ivermectin on social media during the Covid pandemic is a good example of how easily people confuse a drug being approved for one use with it being safe and effective for every use.
Ivermectin is an effective treatment for certain parasitic infections. That doesn’t mean it’s effective for treating Covid-19.
Each proposed use of a medication must be studied separately. The fact that a drug works for one disease tells us very little about whether it will work for another. Just as studies on rats don’t necessarily translate to humans.
Medicine is full of examples where treatments that seemed logical ultimately failed when properly tested.
History repeatedly reminds us that common sense, hope and intuition are poor substitutes for evidence.
That doesn’t mean medicine is always right. Far from it.
Medical recommendations change because evidence changes. Treatments once considered essential are sometimes abandoned. New therapies emerge.
Understanding evolves.
That’s not a weakness of medicine. It’s one of its greatest strengths.
Perhaps that’s where medicine and public debate sometimes part company.
The public often wants certainty. Medicine deals in probabilities.
Patients ask whether a treatment is safe. Doctors instinctively ask a different set of questions.
Medicine isn’t the science of certainty.
It’s the science of making the best evidence-based decision with the information that’s available at the time.
IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.