This guide will help you answer 2.3 Describe the common adverse reactions to medication, how each can be recognised and the appropriate actions required.
Adverse reactions are unwanted or harmful effects caused by medicines. Nearly all medicines may cause reactions, but some are more common than others. A reaction might be mild or severe, and may happen quickly or after repeated doses. It’s important for health and social care workers to be aware of these reactions, how to spot them early, and the right steps to take.
Adverse reactions are sometimes called side effects. They happen when the medicine affects more than just the problem it’s meant to treat. In this guide, we will look at some of the most common ones.
Allergic Reactions
Allergic reactions are the body’s immune response to a substance it sees as foreign or dangerous. Medication allergies can range from mild to severe, and they may develop suddenly.
How to recognise:
- Itchy skin, rashes or hives (raised, red, blotchy skin)
- Swelling, especially of the face, lips, tongue or throat
- Sneezing, runny nose, itchy eyes
- Difficulty breathing, wheezing or shortness of breath
- Severe reaction (anaphylaxis): collapse, rapid heartbeat, feeling faint
What to do:
- Stop the medication.
- Call for emergency help immediately if there is trouble breathing, swelling of the tongue or throat, or collapse. This is a medical emergency (anaphylaxis) and can be life-threatening.
- Follow organisational emergency procedures.
- Record and report the reaction following workplace policy.
Gastrointestinal Reactions
Gastrointestinal means the stomach and intestines. Many medicines can upset the digestive system, especially antibiotics, painkillers, and some medicines for mental health.
How to recognise:
- Nausea (feeling sick)
- Vomiting (being sick)
- Diarrhoea (loose, watery stools)
- Constipation (difficulty passing stools)
- Stomach pain or discomfort
- Appetite changes
What to do:
- Check if the reaction is mild or severe (for example, severe vomiting may cause dehydration).
- Encourage fluids unless there is a medical reason not to.
- Monitor for signs of dehydration (dry mouth, low urine output, feeling very thirsty).
- Inform a manager or the person responsible for care.
- Record the reaction and seek advice from a pharmacist or GP if symptoms persist.
Drowsiness and Sedation
Some medicines, especially those for anxiety, sleep, or allergies, can make people feel very sleepy or slow.
How to recognise:
- Unusual sleepiness
- Difficulty waking up or staying alert
- Slurred speech
- Confusion
- Poor coordination or slow movement
What to do:
- Check for safety risks if the person is unsteady.
- Support the person, keeping them safe from falls.
- Do not allow them to drive.
- Record and report the reaction.
- Consult a healthcare professional if the reaction is severe or ongoing.
Movement Problems (Motor Reactions)
Certain medicines can affect muscles or movement. This happens often with medicines used for mental health conditions, like antipsychotics.
How to recognise:
- Tremors (shaking)
- Stiff muscles
- Difficulty moving, walking, or speaking
- Unusual facial movements (grimaces, twitches)
- Restlessness or agitation
What to do:
- Monitor for changes in movement, report immediately if new or worsening symptoms appear.
- Record details for the health professional.
- Do not stop the medication unless told by a doctor, as sudden withdrawal might be harmful.
Skin Reactions
Skin is often the first place to show that something is wrong with a medicine. Skin reactions can range from mild to severe.
How to recognise:
- Rash (may be flat, raised, red, or blistered)
- Itching
- Swelling
- Peeling skin
- Sensitivity to sunlight (burns easily)
What to do:
- Stop the medication if severe or spreading.
- Inform a healthcare professional right away.
- For mild reactions, keep the area clean and watch for changes.
- Record the nature, timing, and development of the rash.
Headache and Dizziness
Many medicines list headache or dizziness as common side effects. This can happen if blood pressure drops, blood sugar changes, or the brain is affected.
How to recognise:
- Complaints of headache
- Light-headed feelings
- Dizziness, especially on standing up
- Unsteady on feet
What to do:
- Help the person to sit or lie down until symptoms ease.
- Prevent falls.
- Check if symptoms improve after resting.
- Record and report persistent or severe cases.
Changes in Mental State
Some medicines may affect mood or thinking. This is common with some antidepressants, antipsychotics, or medicines for epilepsy.
How to recognise:
- Confusion
- Memory problems
- Agitation or restlessness
- Hallucinations (seeing or hearing things that aren’t there)
- Unusual moods, such as low mood or anxiety
What to do:
- Reassure and support the person.
- Remove anything that could cause harm if the person is confused.
- Report and record these changes.
- Seek advice from a health professional without delay.
Blood Changes
Some medicines affect the blood, reducing the number of blood cells or affecting how the blood clots.
How to recognise:
- Unexplained bruising or bleeding (nosebleeds, gums, urine, stools)
- Persistent sore throat or mouth ulcers (possible sign of low white cells)
- Tiredness, pallor (looking pale), or breathlessness (possible sign of anaemia)
What to do:
- Report signs straight away.
- Record observations such as bruises and bleeding.
- Medical review is needed as these reactions can be serious.
Heart and Blood Pressure Changes
Some medicines affect the heart or blood pressure.
How to recognise:
- Palpitations (feeling like the heart is racing or skipping beats)
- Chest discomfort or pain
- Feeling faint, dizzy, or unsteady
- Sudden drop in blood pressure (may cause a collapse)
What to do:
- Help the person to sit or lie down right away.
- Monitor skin colour, breathing, and pulse.
- Call for medical help at once if chest pain or collapse occurs.
- Record and report all details.
Weight Changes
A change in weight can happen over time with some medicines, especially those used for mental health conditions, steroids, and insulin.
How to recognise:
- Noticeable weight gain or loss
- Swelling in the face, legs, or ankles
- Change in appetite
What to do:
- Monitor weight regularly, as required by the care plan.
- Encourage healthy eating.
- Record changes and report unexplained gains or losses for medical review.
Urinary and Kidney Reactions
Some medicines can affect the kidneys or bladder.
How to recognise:
- Trouble passing urine or new incontinence
- Less urine produced
- Swelling in ankles or feet
- Changes in urine colour or smell
What to do:
- Record urine output and changes.
- Encourage drinking fluids, unless advised not to.
- Report issues to the relevant professional.
Liver Reactions
The liver processes most medicines. When affected, symptoms might appear slowly.
How to recognise:
- Yellow skin or eyes (jaundice)
- Itchy skin
- Dark urine, pale stools
- Tummy pain on the right side
What to do:
- Record symptoms as soon as seen.
- Communicate straight away with healthcare staff.
- Medical assessment is needed.
Monitoring for Adverse Reactions
Being alert to changes in a person’s condition is key. Many people might not link a new symptom to a medication. It’s important to look for any new or worsening problems, especially soon after starting a new medicine or changing the dose.
What to observe:
- Behaviour changes
- Physical changes (such as rash or swelling)
- Eating and drinking patterns
- Toilet habits
- Sleep patterns
What to record and report:
- What happened
- When it started
- Any possible trigger or pattern
- Actions taken and results
Always follow your workplace’s reporting procedures. This helps health staff decide what steps are needed next and prevents serious harm.
Seeking Immediate Help
Some adverse reactions are emergencies. The following need fast medical attention:
- Difficulty in breathing
- Swelling of the mouth, tongue, throat or face
- Severe rash covering most of the body
- Chest pain
- Sudden confusion or collapse
Call for help straight away and act in line with your emergency policy.
Preventing and Managing Reactions
You cannot predict every reaction, but you can reduce risk by:
- Checking allergies before giving medication
- Double-checking doses
- Looking out for changes after starting or changing medicines
- Communicating clearly with other staff, family, and the person receiving care
Record everything accurately and share new concerns without delay. Always follow the care plan and keep medical staff informed of any concerns.
Final Thoughts
Adverse reactions to medication are common in all care settings. Recognising them early and responding in the right way can make a big difference. Reactions can present in many forms, from a simple skin rash through to serious life-threatening emergencies such as anaphylaxis. Some reactions may seem minor but, if left untreated, could become more serious.
By learning the signs of these reactions and responding using your organisation’s policies, you help protect those you care for. Always observe, record, and report changes. Good communication with health professionals supports safe medication use. With these steps, you play a vital role in maintaining safety and well-being in your workplace.
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