Medication Safety: How to Avoid Common Medicine Problems

Introduction

Medicines are among the most effective tools available in modern healthcare — and among the most common sources of preventable harm. Medication errors, unrecognised side effects, harmful drug interactions, and unsafe transitions between care settings affect people across all ages and conditions.

This guide is for patients, families, and carers who want to understand medication safety: how to keep an accurate medicine list, what to watch for, when to seek a pharmacist review, and when a medicine problem needs urgent attention.

It does not replace advice from your clinician or pharmacist, and it does not provide dosing guidance. Every person’s situation is different. Use this guide to ask better questions and recognise warning signs — not to make medicine changes independently.

Key Points

Keep an accurate, up-to-date list of all your medicines, including over-the-counter products and supplements
Hospital discharge, new diagnoses, and seeing multiple specialists are high-risk times for medicine problems
Never stop or change prescribed medicines without advice from your clinician or pharmacist
A pharmacist medicines review is one of the most valuable steps you can take after a hospital admission or when taking multiple medicines
Some medicines require dose adjustment or extra caution in kidney disease, liver disease, older age, or pregnancy
Falls, confusion, bleeding, and low blood sugar are common medicine-related harms that are often preventable
Supplements and herbal products can interact with prescribed medicines — always disclose them to your clinician and pharmacist

Why Medication Safety Matters

Taking multiple medicines — particularly in the context of multiple chronic conditions, older age, or recent hospitalisation — creates real complexity. The risks are not rare:

Medicine errors affect millions of people each year worldwide and are a leading cause of preventable hospital admissions
Drug interactions occur when two or more medicines affect each other’s action, sometimes dangerously
Duplicate treatment happens when the same medicine (or medicines from the same class) is prescribed by different clinicians without coordination
Polypharmacy — taking five or more medicines simultaneously — is increasingly common and increases the risk of side effects and interactions
Discharge transitions are among the highest-risk times: medicines may be started, stopped, or changed in hospital without clear communication home
Self-medication with over-the-counter products, supplements, or old prescriptions adds further complexity that clinicians may not know about

Understanding these risks is not meant to cause alarm. Most people take their medicines safely. But knowing where the risks lie — and how to reduce them — makes a genuine difference.

Keep an Accurate Medicine List

An up-to-date medicine list is the single most practical tool for medication safety. Take it to every appointment, every hospital visit, and every pharmacy.

What Your Medicine List Should Include

For each medicine:

The name of the medicine (both generic and brand name if known)
The dose as written on the label
When you take it (morning, evening, with food, etc.)
What it is for (blood pressure, pain, depression, etc.)
Who prescribed it
When it was started

Also include:

Over-the-counter medicines — pain relievers, antacids, antihistamines, cold and flu products, sleep aids
Vitamins and mineral supplements — including vitamin D, calcium, iron, fish oil, magnesium
Herbal and complementary products — including St John’s Wort, ginkgo, garlic supplements, valerian, and others
Skin patches, inhalers, eye drops, and creams — these are medicines too
Known allergies and adverse reactions — note the medicine and what happened

Keeping It Current

Update your list after every hospital admission, specialist visit, or medicine change
Carry it in your wallet, phone, or medication bag
Make sure your pharmacist and GP have the same list
If a family member or carer manages your medicines, they should have a copy

High-Risk Times for Medicine Problems

Medicine problems can happen at any time, but certain situations significantly raise the risk.

Hospital Discharge

Medicines are the most common source of problems after discharge. A hospital admission often involves medicines being started, stopped, or changed — and getting this right at home requires careful planning. Old supplies of medicines at home may conflict with new prescriptions; instructions may be unclear. See Hospital Discharge and Recovery for a detailed guide to managing this transition.

After Surgery

Pain medicines prescribed after surgery may interact with regular medicines or cause side effects such as constipation, drowsiness, or falls. Instructions about duration — how long to take them — are essential.

Seeing Multiple Specialists

When a GP, cardiologist, nephrologist, endocrinologist, and other clinicians are all prescribing, the risk of duplicated medicines or conflicting treatment increases. No single clinician may have the complete picture. A pharmacist or GP can review the full list for conflicts.

After a New Diagnosis

Starting a medicine for a new condition may interact with existing medicines. This is particularly common when adding blood pressure medicines, diabetes medicines, or pain medicines.

After Kidney Function Changes

Many medicines are processed through the kidneys. If kidney function declines — including after an acute illness — doses may need adjustment or medicines may need to be paused or changed. See Managing Chronic Kidney Disease.

After Falls or Confusion

A fall or new episode of confusion can be caused by a medicine — particularly sedating medicines, blood pressure medicines, or diabetes medicines causing low blood sugar. A medicine review after a fall is a standard and valuable step.

When Carers Change

When responsibility for medicines shifts — between family members, between home and hospital, or between care providers — errors are more likely. Clear handover communication is essential.

New, Stopped, and Changed Medicines

When your medicine list changes, it is important to understand exactly what has changed and why.

Reconcile Your Lists

After any hospitalisation or major medical encounter, compare your old medicine list with the new one. Identify what was added, what was stopped, and what was changed. If anything is unclear, ask before leaving hospital or at your first post-discharge pharmacist or GP visit.

Do Not Restart Old Medicines Without Advice

Medicines that were stopped in hospital — including blood pressure medicines, diabetes medicines, and kidney medicines — may have been stopped for a good reason. Do not restart them without advice from your GP or pharmacist.

Check for Duplicate Medicines

Duplication can occur when a medicine from the same class is prescribed by two different clinicians, or when a brand-name medicine and a generic version of the same drug are both supplied. Ask your pharmacist to check for duplicates.

Ask What Each Medicine Is For

You have the right to understand why you are taking each medicine. Knowing its purpose helps you recognise relevant side effects and understand why it should or should not be continued.

Ask About Short-Term Medicines

Some medicines — antibiotics, pain medicines, short-term steroids — are intended for a defined period. Confirm when they should be stopped.

Side Effects and Interactions

All medicines carry the possibility of side effects. Many are mild or manageable; some are serious and need prompt attention.

Common Side Effects to Know About

Dizziness and light-headedness — particularly with blood pressure medicines; can cause falls
Sedation and drowsiness — with sleeping tablets, antihistamines, strong pain medicines, some antidepressants, and muscle relaxants
Confusion — particularly in older adults; can be caused by anticholinergic medicines, sedatives, or opioids
Nausea and stomach upset — common with antibiotics, anti-inflammatory medicines, and some heart medicines
Constipation — very common with opioid pain medicines
Low blood pressure on standing — can cause dizziness and falls; related to blood pressure medicines and diuretics
Low blood sugar (hypoglycaemia) — with certain diabetes medicines; see Diabetes Medicines section below
Easy bruising and bleeding — with blood thinners
Rash or skin reactions — ranging from mild to severe allergic reactions
Cough — a recognised effect of ACE inhibitor blood pressure medicines

Not every side effect means a medicine needs to be stopped — discuss any concerns with your clinician or pharmacist before making changes.

Drug Interactions

Interactions can increase or decrease how well a medicine works, or cause new side effects when two medicines are combined. Common interaction categories include:

Medicines that both thin the blood (increased bleeding risk when combined)
Medicines that both lower blood pressure (additive low blood pressure)
Medicines that both cause drowsiness (additive sedation)
Medicines that affect liver enzymes, which process many drugs

Alcohol can also interact with many medicines — including sedatives, pain medicines, blood thinners, and diabetes medicines. Ask your pharmacist about alcohol and your specific medicines.

Medicines and Falls Risk

Several types of medicine increase the risk of falls. This is particularly important for older adults and anyone who has already had a fall.

Medicines That Raise Fall Risk

Sleeping tablets, sedatives, and benzodiazepines — cause drowsiness, impaired balance, and slowed reaction time
Strong pain medicines (opioids) — cause drowsiness and can impair balance
Blood pressure medicines — particularly if causing dizziness when standing (orthostatic hypotension)
Diuretics (fluid tablets) — can cause low blood pressure and dizziness
Diabetes medicines — if causing hypoglycaemia (low blood sugar), which causes weakness and confusion
Some antidepressants and nerve pain medicines — can cause dizziness, sedation, or low blood pressure
Antihistamines — older antihistamines have sedating effects

Taking multiple medicines that each modestly raise fall risk can together create significant hazard. A pharmacist or clinician can assess fall-related medicine risks.

Seek a medication review after any fall. Never stop prescribed medicines without clinician or pharmacist guidance.

See: Falls Prevention: How to Reduce Fall Risk

Medicines and Kidney Disease

Kidney function affects how many medicines work in the body, and some medicines can affect the kidneys themselves.

How CKD Affects Medicine Safety

In people with chronic kidney disease (CKD), some medicines may:

Accumulate to higher levels than intended because the kidneys cannot clear them efficiently
Cause direct damage to the kidneys
Require dose adjustment or substitution

NSAIDs and Anti-inflammatory Medicines

Ibuprofen, naproxen, and other non-steroidal anti-inflammatory drugs (NSAIDs) reduce blood flow to the kidneys and can worsen kidney function, particularly with regular use. People with known kidney disease are generally advised to avoid them, or use them only briefly and under clinical guidance. Always ask a pharmacist or clinician before using anti-inflammatory medicines regularly.

Contrast Dyes for Scans

Iodinated contrast agents used in CT scans and some other imaging procedures can affect kidney function in people with CKD. Always inform the imaging team of your kidney function before any contrast procedure.

Sick Day Advice

During acute illness — particularly with vomiting, diarrhoea, fever, or reduced fluid intake — some medicines (including blood pressure medicines, diuretics, and certain diabetes medicines) may need to be temporarily paused. Your clinical team can advise on a personalised sick day plan. Do not stop medicines without guidance; seek advice promptly when acutely unwell.

See: Chronic Kidney Disease Hub and Managing Chronic Kidney Disease

Blood Thinners and Bleeding Risk

Blood-thinning medicines — including anticoagulants and antiplatelet agents — are prescribed for important reasons such as preventing stroke in atrial fibrillation, or preventing clots after a heart attack. They require careful management.

Types of Blood-Thinning Medicine

Direct oral anticoagulants (DOACs) — apixaban, rivaroxaban, dabigatran, edoxaban
Warfarin — requires regular INR blood tests and dietary consistency
Antiplatelets — aspirin, clopidogrel, ticagrelor

Bleeding Risk

People taking blood thinners bruise more easily. More serious bleeding — including into the gut, brain, or from cuts that are hard to stop — is a genuine risk that should be discussed with your prescriber.

Signs of normal, expected bruising are different from serious bleeding. Serious bleeding requires urgent medical attention.

Interactions and Missed Doses

Many medicines, supplements (including fish oil and garlic at high doses), and foods (for warfarin, particularly vitamin K-containing foods) can affect blood-thinning medicines. Always tell your pharmacist and clinician about everything you take.

If you miss a dose of a blood-thinning medicine, do not double up — ask your pharmacist or clinician for guidance specific to your medicine.

Urgent Red Flags for Bleeding

Seek emergency help for:

Heavy or uncontrollable bleeding from any site
Blood in urine (red or dark brown)
Black, tarry, or blood-streaked stools
Vomiting blood or material that looks like coffee grounds
Sudden severe headache (possible brain bleed)
Bruising that is rapidly spreading or unusually large

See: Atrial Fibrillation and Common Heart Medications and Their Side Effects

Diabetes Medicines

Medicines for diabetes carry specific safety considerations, particularly around low blood sugar and changes during illness or hospital admission.

Low Blood Sugar (Hypoglycaemia)

Some diabetes medicines — including insulin and certain tablet medicines (sulphonylureas such as glipizide and glibenclamide) — can cause the blood sugar to fall too low. Symptoms include shakiness, sweating, pale skin, confusion, rapid heartbeat, and weakness.

Treatment involves raising blood sugar with a fast-acting carbohydrate source. If someone is unconscious or unable to swallow safely, call emergency services immediately.

Sick Days and Hospital Admissions

During illness or hospital admission, blood sugar control may change significantly. Some diabetes medicines need to be paused during illness, surgery, or when eating is restricted. Your clinical team will advise — do not stop or adjust medicines without guidance.

Kidney Function and Diabetes Medicines

Some diabetes medicines require dose adjustment or are not suitable at lower levels of kidney function. This is reviewed by a clinician as part of ongoing diabetes and CKD management.

Changed Eating Patterns

Significant changes in food intake — during illness, after surgery, or at hospital discharge — can affect blood sugar and how diabetes medicines work. Contact your diabetes team or GP promptly if you are unwell or eating much less than usual.

See: Diabetes Hub and Managing Chronic Kidney Disease

Pain Medicines

Pain medicines range from mild and well-tolerated to potent and high-risk. Understanding which type you are taking matters.

Paracetamol (Acetaminophen)

Paracetamol is widely used and generally well tolerated at recommended doses. Exceeding the recommended dose — or combining paracetamol from multiple sources (such as taking a paracetamol product separately from a combined cold and flu preparation that also contains paracetamol) — carries risk of liver harm. Check labels carefully.

NSAIDs (Anti-inflammatory Medicines)

Ibuprofen, naproxen, and similar medicines are effective for pain and inflammation but carry risks with regular use — including stomach ulcers and bleeding, raised blood pressure, worsening kidney function, and fluid retention. They are generally not suitable for people with kidney disease, certain heart conditions, or stomach ulcer history. Ask a pharmacist before using them regularly.

Opioid and Strong Pain Medicines

Opioids (codeine, tramadol, oxycodone, morphine, hydromorphone, fentanyl) carry risks of sedation, constipation, respiratory depression (with high doses), dependence, and falls. They should be used at the lowest effective dose for the shortest appropriate time. Constipation with opioids is almost universal — a bowel management plan is standard when these medicines are prescribed.

Always check with your clinician or pharmacist before combining pain medicines, and before using any pain medicines with other sedating drugs or alcohol.

Antibiotics and Short-Term Medicines

Completing a Course

If you are prescribed a course of antibiotics, complete it as directed — even if you feel better before it is finished. Stopping early can allow the infection to recur and contribute to antibiotic resistance.

Side Effects

Antibiotics can cause nausea, stomach upset, diarrhoea, and occasionally allergic reactions. Thrush (oral or vaginal) is common after antibiotics because they affect the normal bacterial environment. Some antibiotics interact significantly with other medicines, including warfarin.

When to Call Back

Contact your clinician if symptoms are not improving as expected, if you develop a rash or any sign of an allergic reaction, or if you develop diarrhoea that is severe or contains blood or mucus.

Supplements and Herbal Products

Natural does not mean safe when combined with prescribed medicines.

Known Interactions

Several supplements interact with prescribed medicines:

St John’s Wort — interacts with many medicines including antidepressants, contraceptives, anticoagulants, and HIV medicines
Fish oil and garlic at high doses — may increase bleeding risk when combined with blood thinners
Ginkgo biloba — potential interactions with anticoagulants and antiplatelets
Valerian and kava — sedating effects that combine with other sedating medicines
Vitamin K (in high-dose supplements or fortified foods) — affects warfarin’s activity

Always Disclose

Tell every clinician and pharmacist about all supplements and herbal products you take. This includes products described as “natural”, “traditional”, or “complementary”. They can interact with prescribed medicines in ways that are not always obvious from the labels.

Medication Safety for Dementia or Carer Support

When a person has dementia or significant cognitive difficulties, medicine management requires additional planning.

Practical Safety Tools

Blister packs / dose administration aids — pharmacists can pack medicines into labelled blister packs organised by day and time, reducing the risk of missed or double doses
Pharmacy packing services — available through most community pharmacies; discuss this with your regular pharmacist
Alarms and reminders — phone alarms, smart dispensing devices, or written charts can prompt medicine taking
Locked storage — where there is a risk of accidental overdose, double-dosing, or medicine being taken by a child, secure storage is an important safety measure
Carer communication — when multiple people help with medicines, a clear written plan and regular communication prevents errors

Medicines Review for People with Dementia

Some medicines carry specific risks for people with dementia — including sedatives, antipsychotics, anticholinergic medicines (found in some bladder, allergy, and stomach preparations), and antihistamines. A pharmacist medicines review can identify these and suggest safer alternatives where possible.

Do not stop or change medicines without speaking to the treating clinician.

See: Dementia Caregiving: Safety, Support, and Planning

What to Ask a Pharmacist or Clinician

These questions help you get the most useful information from any medicine-related appointment:

What is this medicine for?
What has changed from my previous medicines, and why?
What should I not take with it?
What side effects should I watch for, and when do they need attention?
What monitoring does this medicine require (blood tests, blood pressure, etc.)?
What should I do if I miss a dose?
When should this medicine be reviewed or stopped?
Can I take this medicine with my other medicines, supplements, and over-the-counter products?
Does this medicine affect my kidneys or require dose adjustment?
Are there any medicines I should avoid while taking this?

Pharmacists are accessible, highly trained medicines experts. You do not need a referral to speak with a community pharmacist, and a Home Medicines Review (in Australia) or Structured Medication Review (in the UK) can be arranged through your GP to provide a comprehensive assessment at home.

When to Seek Urgent Help

Seek emergency care if you or someone in your care develops:

Difficulty breathing, throat tightening, or severe swelling of the face, lips, or tongue — possible severe allergic reaction (anaphylaxis)
Severe or rapidly spreading rash — particularly if associated with fever or mouth involvement
Fainting or collapse
Chest pain
Severe or uncontrollable bleeding — including from the gut (black stools, vomiting blood), urinary tract, or other sites
Sudden severe headache — particularly if on blood thinners
Confusion, severe drowsiness, or inability to stay awake — particularly after a dose change or new medicine
Seizure
Signs of severe low blood sugar — shaking, sweating, pale skin, rapid heartbeat, confusion, loss of consciousness
Accidental overdose — contact emergency services or a poisons information line immediately
A child or pet who has swallowed medicines — contact emergency services or a poisons information line immediately

If in doubt, do not wait — contact emergency services, a nurse advice line (healthdirect 1800 022 222 in Australia, 111 in the UK), or go to the nearest emergency department.

FAQ

What is medication safety? Medication safety means using medicines in a way that reduces the risk of errors, side effects, interactions, duplicate treatment, missed doses, or unsafe changes. It involves keeping an accurate medicine list, asking the right questions, and knowing when to seek help.

Why is a medicine list important? An up-to-date medicine list helps clinicians and pharmacists check what you take, what has changed, and whether any medicines may interact or duplicate each other. It is especially important at hospital discharge, emergency presentations, and new appointments.

Should I stop a medicine if I think it is causing side effects? Do not stop or change prescribed medicines without medical or pharmacist advice unless you have been explicitly told to do so. Some medicines need careful tapering or review before stopping. Discuss concerns with your clinician or pharmacist first.

Why does kidney function matter for medicines? Some medicines are processed through the kidneys or can damage them. If kidney function is reduced, medicines may accumulate, and doses or choices may need adjustment. This is particularly important in chronic kidney disease and during acute illness.

When should I seek urgent help for a medicine problem? Seek urgent help for difficulty breathing, swelling of the face or throat, severe rash, fainting, chest pain, severe or uncontrollable bleeding, confusion, severe drowsiness, signs of severe low blood sugar, accidental overdose, or if a child has swallowed medicines.