Introduction
You’ve just been to your GP appointment and have been handed a prescription for a new medication. You pick it up from the pharmacy next door. When you get home, you pull the patient information leaflet out of the box and take a glance. The list of possible side effects seems endless. Some sound scary, and others are vague. They might even make you wonder whether this new tablet is worth taking. Surely medicines are meant to make you feel better, not worse?
Side effects are common, even with simple, everyday medicines such as paracetamol. However, the information leaflet is a list of what is possible, not a list of what you will definitely experience. Most side effects are mild and not concerning. They will usually settle down on their own accord as your body gets used to treatment and can be managed fairly easily. Worth remembering before you panic.
Studies show that up to half of all medicines prescribed for long-term conditions are not taken as prescribed. Worries about side effects are one of the main reasons. This is understandable, but not following the agreed treatment plan can have real consequences for your health. It also costs the NHS around £500 million a year in wasted medicines and treating problems that could have been prevented.
Stopping a medication without advice can sometimes cause more harm than the side effect itself. The good news is that most side effects can be simply remedied. Let's look at five of the most common ones, why they happen, and what you can do about them.
Nausea
One of the most common side effects is a queasy, unsettled feeling in your stomach. It can happen with painkillers, antibiotics, antidepressants, and blood pressure tablets.
Why does it happen? Many medicines irritate the lining of your stomach, and some also set off signals in your brain that make you feel sick. Your body is treating the medicine as something new and unfamiliar, but this usually calms down once your system adjusts.
What helps
Take your medicine with food, unless the label says to take it on an empty stomach. If you see "empty stomach," that usually means one hour before eating or two hours after. A plain biscuit, a slice of toast, or a small pot of yoghurt can make a big difference.
If the nausea lasts more than a week or two, speak to your GP or pharmacist. Sometimes a simple change, like taking your dose at bedtime instead of in the morning, can help ease your symptoms.
Drowsiness
Feeling unusually tired or sluggish is common with hay fever tablets, certain painkillers, antidepressants and some blood pressure treatments.
Medicines do not just affect you physically; they can also impact how you feel mentally. Your mood, your focus, your confidence. If a tablet makes you feel "foggy" or slow, it can be frustrating.
What helps
If the tiredness affects your ability to drive or work, do not ignore it, as doing so could put yourself and others at risk. Avoid alcohol, as it makes the drowsiness much worse.
One of the best ways to overcome this side effect is to take your dose in the evening instead, so the worst of it passes while you sleep. Check with your GP or pharmacist if this is a suitable option. That said, many people find drowsiness improves significantly after the first couple of weeks. If you can get through the early stages safely, it often becomes much less noticeable.
Constipation
This one rarely gets talked about, but it is very common. It often happens with iron tablets, some antidepressants, and strong painkillers like codeine or morphine.
Lots of medicines slow down your gut or reduce the amount of fluid in your bowel. This leads to hard stools, discomfort, and bloating. Sometimes, straining can lead to haemorrhoids (piles) and bleeding.
The good news is that constipation is one of the easiest side effects to manage.
What helps
Drink plenty of water. Aim for foods high in fibre, like vegetables, fruit, and wholegrain bread or cereals. Prune juice is a gentle, natural option that works well for many people.
Please do not feel embarrassed to bring this up with your pharmacist. They talk about it every day. They want to help you feel comfortable. Over-the-counter preparations can really make a difference.
If you do experience any bleeding when you open your bowels, make sure you speak to your GP.
Dizziness
That feeling of the room tilting when you stand up is common when starting blood pressure tablets or treatments for anxiety.
Dizziness often happens when a medicine lowers your blood pressure too quickly. It tends to be worse at the start of treatment or after a dose increase. For most people, it is short-lived while your body finds its balance.
What helps
Get up slowly from sitting or lying down. Give your body a moment to catch up before you start walking.
Stay hydrated. Being low on fluids makes dizziness worse.
Try taking your medication in the evening, so that you are settled in bed and not busy trying to get on with your day (check with your GP to make sure this is a suitable time).
If the feeling does not settle after a week, contact your GP. Dizziness is not a symptom to self-manage in the long term. Falls are a real risk, especially for older people with frailer bones.
Dry Mouth
A mouth that feels dry, sticky, or uncomfortable can make it hard to speak or eat. Over time, it can even affect your teeth.
Some medicines work by blocking certain nerve signals in your body. This can reduce how much saliva you make. Saliva helps protect your teeth, so a dry mouth that goes on for a long time is something to take seriously.
What helps
Sip water often throughout the day. Chewing sugar-free gum or eating sugar-free mints can help stimulate your saliva flow; look out for a sweetener called xylitol (but be careful, as this can be toxic to dogs). Fresh pineapple chunks can also help. Avoid too much caffeine or alcohol, which makes the problem worse.
If the dryness is bad, your pharmacist or dentist can suggest saliva substitutes. These come as sprays, gels, or pastilles and can make a real difference.
When to Seek Help
Most side effects are mild and settle as your body adjusts. However, some need urgent attention. If you experience swelling of the face, difficulty breathing, or sudden mood changes, please seek medical help immediately.
When you speak to your GP or pharmacist about side effects, it is helpful to understand your top health priorities. For example:
- "My priority is being able to play with my grandchildren, but this dizziness makes me afraid of falling."
- "I want to stay active, but the nausea is making it hard to go for my daily walk."
Sharing these goals helps healthcare professionals to shape their approach so that it is tailored towards what matters most to you.
Reporting Side Effects
In the UK, you can report any suspected side effect to the Medicines and Healthcare products Regulatory Agency (MHRA) through the Yellow Card scheme. You don't need to prove the medication caused the problem. A suspicion is enough.
Since 1964, over one million reports have been collected, and they've helped identify safety concerns that wouldn't have been spotted otherwise.
You can report online at yellowcard.mhra.gov.uk or call 0800 731 6789.
Your experience matters. Reporting helps make medicines safer for everyone.
The Bigger Picture
Side effects can feel like a good reason to stop a treatment. But research consistently shows that when we struggle to take our medicines as intended, it can make management of our long-term health conditions much more difficult.
Remember, medication is only one of the tools in your toolbox. You also have your healthy habits and the support of your GP practice team and your local pharmacist. If something doesn’t feel right, speak up. It is often possible to change your dose or find a new choice that fits your life better.
Feeling confident in your treatment is key to making sure it works for you. Taking care of your health is a journey, and you do not have to do it alone. Your well-being is the most important part of this process. Looking after yourself is about more than just a pill. It is about your quality of life and the future you want to enjoy.
References
- Sabaté E (ed). Adherence to Long-Term Therapies: Evidence for Action. World Health Organization; 2003. ↩
- Langley C, Bush J, Patel A. The Aston Medication Adherence Study (AMAS). Aston Pharmacy School; 2014. Reported in: PharmaTimes. Drug non-adherence "costing NHS £500M+ a year." December 2014. ↩
- Medicines and Healthcare products Regulatory Agency (MHRA). The Yellow Card Scheme: Guidance for Healthcare Professionals, Patients and the Public. GOV.UK; 2024. ↩
- Pirmohamed M, James S, Meakin S, et al. Adverse drug reactions as cause of admission to hospital: prospective analysis of 18,820 patients. BMJ. 2004;329(7456):15-19. doi:10.1136/bmj.329.7456.15 ↩
- Barnett NL. Medication adherence: Where are we now? A UK perspective. European Journal of Hospital Pharmacy. 2014;21(3):181-184. doi:10.1136/ejhpharm-2013-000373 ↩
This article is for general information. It doesn't replace advice from your own doctor, pharmacist or prescriber.