Medicines explained
Understanding over-the-counter medicines safely
Over-the-counter medicines are the everyday remedies you can buy without a prescription, from pharmacies and often supermarkets, to treat common problems such as pain, coughs, colds, indigestion and allergies. They are generally safe and effective when used as intended, and they let people manage minor illnesses themselves with support from a pharmacist. But because they are so easy to buy, it is easy to forget they are still real medicines that can cause harm if misused. This guide explains what over-the-counter medicines are, how to read the label, how to avoid common mistakes such as taking the same ingredient twice, and when it is important to ask a pharmacist or GP for advice. It names no doses.
Education and reference only. This article explains how treatments work in plain language — it contains no doses and is not a substitute for advice from your doctor or pharmacist. Always discuss your own treatment with a qualified clinician.
What are over-the-counter medicines?
Over-the-counter medicines, often shortened to OTC, are those you can buy without a prescription to treat minor, short-term conditions. In the UK they fall into two broad groups: general sales list medicines, sold in many shops and supermarkets, and pharmacy medicines, kept behind the pharmacy counter and sold under a pharmacist's supervision. Common examples include pain relievers, cough and cold remedies, antihistamines for allergies, indigestion and heartburn treatments, and creams for skin problems. They are chosen because they are considered safe enough for people to use themselves with the information provided. Even so, they remain genuine medicines with active ingredients that can cause side effects, interact with other medicines, or be unsuitable for certain people, which is why using them thoughtfully matters.
Read the label and leaflet
The single most useful habit is to read the label and the patient information leaflet before taking any medicine, and to keep the leaflet in case you need it. The label and leaflet tell you what the medicine is for, how much to take and how often, the maximum in a day, and how long you can safely use it before seeking advice. They also list who should not take it, possible side effects, and warnings, such as not drinking alcohol or not driving if it makes you drowsy. Following these instructions exactly is the best way to stay safe. If anything is unclear, or if you are choosing between products, ask the pharmacist, who is there specifically to help you pick a suitable medicine and use it correctly.
Avoid doubling up on ingredients
A common and important mistake is accidentally taking the same active ingredient in more than one product at once, known as doubling up. Many combined cold and flu remedies, painkillers and night-time preparations contain the same pain-relieving or decongestant ingredients under different brand names. Taking two products together, or an OTC medicine alongside a prescribed one containing the same ingredient, can add up to too much and cause serious harm, particularly with certain pain relievers where overdose can damage the liver. Always check the list of active ingredients on each product, not just the brand name, and avoid combining medicines with overlapping ingredients unless a pharmacist confirms it is safe. If in doubt, ask before you take anything, especially when treating several symptoms at once.
Check who it suits and interactions
An over-the-counter medicine that is fine for one person may not suit another. Some are not recommended in pregnancy or breastfeeding, for young children, or for people with certain conditions such as high blood pressure, stomach ulcers, kidney or liver problems, or asthma. Medicines can also interact with each other, so an OTC product may clash with a prescribed medicine, a herbal remedy or a supplement, changing how well either works or increasing side effects. This is why it helps to tell the pharmacist what else you take and any health conditions you have before buying something. Keep medicines in their original packaging, store them safely out of reach of children, and check the expiry date, discarding anything out of date.
When to ask a pharmacist or GP
A community pharmacist is a highly trained, freely accessible source of medicines advice, and you do not need an appointment. Ask them if you are unsure which product to choose, whether a medicine is safe with your other medicines or conditions, or how long to use it. Under the NHS Pharmacy First service in England, pharmacists can also advise on, and where appropriate supply treatment for, a number of common conditions. See a GP or call NHS 111 if symptoms are severe, last longer than the label suggests, or keep coming back, as these may need proper assessment rather than continued self-treatment. If someone takes too much of any medicine, contact NHS 111 or a pharmacist for advice, and in a serious emergency, such as collapse or difficulty breathing, phone 999.
In short
Key takeaways
- Over-the-counter medicines treat minor conditions without a prescription but are still real medicines that can cause harm if misused.
- Always read the label and patient information leaflet, and follow the instructions on how much, how often and for how long.
- Avoid doubling up: check active ingredients, not just brand names, so you do not take the same ingredient in two products.
- Some medicines are unsuitable in pregnancy, for children, or with certain conditions or other medicines — tell the pharmacist what you take.
- Ask a pharmacist for free advice; see a GP or call NHS 111 for severe or persistent symptoms, and 999 for a serious emergency.
Answers
Frequently asked questions
Are over-the-counter medicines completely safe?
They are safe for most people when used as directed, but they are still real medicines that can cause side effects, interact with others, or be unsuitable for some people. Reading the label, avoiding doubling up, and asking a pharmacist if unsure keeps you safe.
What does doubling up mean and why is it risky?
Doubling up means taking the same active ingredient in more than one product, for example two cold remedies with the same painkiller. This can add up to too much and cause harm, including liver damage with some pain relievers. Always check the active ingredients.
When should I ask a pharmacist rather than self-treat?
Ask if you are unsure which product to choose, whether it suits your health conditions or other medicines, or how long to use it. See a GP or call NHS 111 if symptoms are severe, persistent or recurring, and phone 999 in a serious emergency.
Sources
Where this is drawn from
- Medicines and Healthcare products Regulatory Agency (MHRA) — Guidance on using medicines safely.
- NHS — How to use medicines safely and the Pharmacy First service.
- British National Formulary — Guidance on prescribing and over-the-counter medicines.
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