As medicines are a crucial part of medical treatment, it is important to have a good understanding of them.
Some medicines are available from pharmacists or supermarkets, while others require a prescription from your GP or another healthcare professional.
The availability of medicines depends on the level of supervision experts believe is necessary before you use a particular medicine.
Under laws governing the supply of medicines, you can obtain medicine under three categories:
These are explained in more detail below.
Prescription-only medicines need a prescription issued by a GP or another suitably qualified healthcare professional.
You then take the prescription to a pharmacy or a dispensing GP surgery to collect your medicine.
Pharmacy medicines are available from a pharmacy without a prescription, but under the supervision of a pharmacist.
You will need to ask staff at the pharmacy for this type of medicine because it is kept behind the counter and is not available on the pharmacy shelves.
The pharmacist will check the medicine is appropriate for you and your health problem. They will ask you questions to ensure there is no reason why you should not use the medicine.
General sales list medicines can be bought from pharmacies, supermarkets and other retail outlets without the supervision of a pharmacist. These are sometimes referred to as over-the-counter medicines.
Over-the-counter medicines include those that treat minor self-limiting complaints people may feel are not serious enough to see their GP or pharmacist about.
The main prescribers are called independent prescribers, which include:
Independent prescribers can assess someone and prescribe a medicine as part of that person's care.
There are also supplementary prescribers, who can prescribe any medicine for any condition within their competence, with the agreement of an independent prescriber and the patient.
Read more about who can write a prescription.
New medicines tend to be licensed in the prescription-only medicines category so that healthcare professionals can supervise their use during the first few years they are available.
If a medicine proves safe in large numbers of patients over several years, the regulatory agency may consider changing its status from prescription-only to pharmacy.
If it continues to be safe for another few years, a switch to general sales list status may be considered so it can be sold directly from retail outlets.
If a medicine switches from prescription only to pharmacy, or from pharmacy to the general sales list, the active ingredient remains exactly the same. This means the medicine is just as effective as when it had to be prescribed by a qualified prescriber.
It also means there is the same risk of side effects if you take too high a dose or do not follow the instructions on the label. It is therefore important you follow the instructions carefully.
In the UK, before any medicine can be used to treat people, it has to be licensed. Licences are only granted if high standards of safety and quality are met throughout the development process and the product works for the purpose intended.
In the UK, licenses can only be granted by the Medicines and Healthcare Products Regulatory Agency (MHRA) and the European Medicines Agency (EMA).
Potential medicines are first thoroughly researched using tissue culture, computer analysis techniques and animal testing.
If strict standards of safety and effectiveness are met, clinical trials involving humans can then be used. If a medicine passes all the phases of clinical trials, it can be licensed for wider use.
The whole process from discovery to licensing can take around 10 to 15 years.
Read more about licensing medicines.
No medicine is completely risk free, but attempts are made by the MHRA and EMA to ensure any medicine approved for widespread use is as safe as possible.
As well as a strictly monitored development process, medicines continue to be carefully regulated after they have been granted a license. This involves checking for problems, such as reports of previously unknown side effects.
In rare cases, medicines may be withdrawn if there are significant safety concerns or if the risks of the medicines outweigh the potential benefits.
You can help the MHRA monitor the safety of medicines by reporting any suspected side effects to the Yellow Card Scheme. Reports can also be made on behalf of someone you're caring for.
The MHRA is the UK medicines watchdog. Its Yellow Card Scheme collects reports of side effects for all medicines (including complementary medicines) and vaccines.
If a new side effect is found, the MHRA will review the way the medicine can be used and alert the public to the potential risks.
Read more about medicine safety and regulation.
Many medicines have at least two different names – a brand name and a generic name.
The brand name is usually what the medicine is called by the company that first discovered and developed it. The generic name is the name of the active ingredient in the medicine that makes it work.
Initially, for a few years the company that developed the medicine is the only one that can sell it, which means they can choose the price.
To make a profit from the very costly development process, this usually means the medicine is very expensive at this point.
Generic copies are allowed to be made once this period ends. Generic medicines are usually as effective as the brand-name medicine because they contain the same active ingredients.
Generic medicines are used more often for treatment because they are as effective as the original medicine, but cost far less.
Read more about generic and brand-name medicines.