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Medications glossary


AC (ante cibum)

An abbreviation used by doctors to mean 'before food' when they prescribe medicine. The medicine works best with as little food as possible in the stomach. You could take it one hour before a meal or two hours after a meal.


Acute is a term used to refer to something severe and often sudden. For example, you may have an acute reaction to a medication.


Anti-anxiety medication is medication used to treat the symptoms of anxiety.


A medicine used to treat depression by acting on the naturally occurring chemicals in the brain (serotonin, noradrenaline and/or dopamine) and how these chemicals (neurotransmitters) work to transmit messages between brain cells.


There are different groups of medicines that can all be used to treat depression. These include SSRIs (e.g. fluoxetine), SNRIs (e.g. venlafaxine) and tricyclics (e.g. amitriptyline).


Medicines referred to as ‘antipsychotics’ may also be used to treat depression (e.g. quetiapine).


Medicines traditionally called ‘antidepressants’ are also prescribed to treat other conditions like anxiety, OCD or PTSD as well.


A medicine used to treat psychosis.


Medicines used to treat anxiety, including diazepam and lorazepam. Sometimes antipsychotics or beta blockers are also used to relieve the symptoms of anxiety.

Atypical antipsychotic

A newer medicine used to treat psychosis. Examples include olanzapine, quetiapine, risperidone and aripiprazole. Sometimes called second-generation antipsychotics.



Very old group of medicines no longer used for mental health conditions. They are sometimes used in the treatment of epilepsy.

BD (bis die)

Twice a day (every 12 hours if possible). So, an example might be 8am and 8pm.


A group of medicines used to treat anxiety and sleep problems. Examples are diazepam and lorazepam.

Branded medicine

A name that the company gives to its medicine. Not the actual medicine name. For example, Prozac® is one brand name for the medicine fluoxetine.

British National Formulary (BNF)

Reference book for health professionals about all medicines available in the UK.



Medicines that you take by mouth. Often oval-shaped to help you swallow them. They may contain gelatin.


Pharmacist. A health professional working in a community pharmacy or hospital who is trained to give advice about medicines.

Chronic Medication Service (Scotland)

A service offered by community pharmacists (chemists) in Scotland for NHS patients who have long-term conditions requiring medicines. It includes a repeat prescription service and review of your medicines by the pharmacist.

Community Pharmacy Urgent Supply Service (CPUS) [Scotland]

A service for NHS patients in Scotland. The community pharmacist can supply a small amount of medicines for long-term illnesses if the doctor is not available (for example at the weekend).

Controlled drug

A medicine with special rules and laws regarding how it is supplied when prescribed. These medicines are normally stored in a locked cupboard in the pharmacy or on the hospital ward. Examples include diazepam and methylphenidate.

Controlled release

A medicine which is absorbed by the body slowly when it is taken. An example is a controlled-release tablet, which is taken once every 24 hours (compared to the normal-release tablet, which is taken two or three times daily).


Dependence (drug dependence)

Being dependent (on drugs or alcohol for example) means you don’t feel you can function without them. If you have a high level of dependence you may experience withdrawal symptoms when you stop taking them.

Depot injection

An injection of medicine given into the muscle of the arm, leg or buttock. It allows medicine to be released into the body very slowly over weeks or months. Usually depot injections of antipsychotics are given weekly, fortnightly or monthly.


A medicine or substance which can bring on a low mood. Alcohol can act as a depressant in some people.

Discontinuation symptoms

Uncomfortable effects that you may experience if you stop taking a medicine, especially if you stop quickly or suddenly. See also withdrawal symptoms.


A chemical made by the brain. It affects mood, emotions and movement. Levels of dopamine can be affected by some medicines for schizophrenia.


Early Intervention In Psychosis (EIIP)

A service which works with people after their first experience of psychosis. Services usually work with people aged 14-35 and provide a range of support and treatments that may include medication. See antipsychotics.

Electrocardiogram (ECG)

A medical test which records the electrical activity of the heart. You might have an ECG if you are having chest pains or an abnormal heart rate. It is a painless procedure that can be carried out by your GP or at a hospital.

Electroencephalogram (EEG)

A medical test which records the electrical activity of the brain. It can be used to diagnose and manage a range of conditions including epilepsy and insomnia as well as brain injuries. An EEG is painless, takes 30-45 minutes and rarely causes any side effects.

Emergency supply

A method where a community pharmacist can give a small amount of prescription-only medicine without a doctor’s prescription if the doctors' surgery is closed. Usually only used at weekends or evenings for medicines that should be taken continuously. The pharmacist can only supply medicines that the patient has been prescribed before by their doctor.


First-generation antipsychotic

Also known as a typical antipsychotic, this is the original or older type of antipsychotic.


Generic medicine

A medicine that is an exact copy of an original brand of a medicine. It works in the same way as the original but may be cheaper as the manufacturer does not have to pay for the cost of research of the new medicine.


Intramuscular (IM)

Some medicines and vaccines are given IM, which means they are injected into the muscle by a nurse or doctor. Usually the top of the arm, side of the leg or the buttock area is used.

Intravenous (IV)

Some medicines are given IV. This means they are injected directly into a vein. IV medicines act very quickly so they are useful in emergency situations or in a hospital. Some street drugs are also taken this way.


Licensed medicine

A medicine that has been approved by the health authority of a particular country for use to treat certain illnesses.

Lithium toxicity

Lithium is a medicine commonly prescribed to treat bipolar disorder. If the dose of lithium is too high, the patient can get lithium toxicity, which causes side effects such as nausea, tremor and kidney problems. The doctor will usually reduce the lithium dose or may stop lithium treatment. People who are prescribed lithium will have regular blood tests to look for early signs of lithium toxicity.

Long-acting injection

An intramuscular (IM) injection that is given weekly, fortnightly or monthly. The medicine is slowly released into the body to avoid the need for daily doses. Some antipsychotics are available as long-acting injections.


Major tranquiliser

The old name for antipsychotics.

Medicines Use Review (MUR) [England and Wales]

A free service offered by community pharmacists. The pharmacist will discuss your medicines with you in private. They will help you with any problems with your medicines, answer questions you may have and help you to get the best from your medicines. Any pharmacist can do this for you but there is a formal scheme for this in England and Wales.

Microgram (mcg)

A measure of weight. Some medicines are prescribed in doses of micrograms. There are 1000mcg in one milligram.

Milligram (mg)

A measure of weight. Some medicines are prescribed in doses of milligrams. There are 1000mg in one gram.

Millilitre (ml)

A measure of volume. Some liquid medicines are prescribed in millilitres. There are 1000 ml in one litre.

Minor tranquiliser

The old name for anxiety medications.

Monoamine oxidase inhibitors (MAOIs)

A type of antidepressant. This group of antidepressants can interact with some foods that contain tyramine. People that are prescribed them have to follow a careful diet.

Mood stabiliser

A type of medicine used to treat bipolar disorder. Mood stabilisers help to balance moods to avoid periods of mania or depression. They are usually taken long-term (for several months or years).


National Institute for Health and Care Excellence (NICE)

Provides national guidance and advice to improve health and social care.


This is the old name for the group of medicines now called antipsychotics.

New Medicines Service (NMS)

This is a service provided by community pharmacies, which provides advice and support to people with long-term conditions that have been prescribed a medicine for the first time. It is initially focused on particular patient groups and conditions.


OD (once a day)

OD is an abbreviation used by doctors to mean ‘once a day’ when they prescribe medicines.


When medicines are made, the drug manufacturer applies for a licence that means the medicine has been approved for a specific condition and group of people. ‘Off-label’ use means that the medicine is being used in a way that is different to that described in the licence. Doctors may have found that the medicine works very well for another condition, and the use may be supported by expert groups, but the drug manufacturer has not extended the licence.

Over the counter (OTC)

Over-the-counter (OTC) medicines are medicines you can buy without a prescription from a shop, e.g. paracetamol.


An overdose is when a drug is taken in quantities that are larger than recommended, either on purpose or by accident. It can result in serious illness or death. If you have taken an overdose on purpose or by accident, call 999 immediately.


PC (post cibum)

An abbreviation used by doctors to mean 'after a meal' when they prescribe medicines. Some medicines are affected by food and so should be taken at meal times.


A healthcare professional who is an expert on medicines and focuses on safe and effective medication use. They can work in a high-street pharmacy or in a hospital.

PO (per os)

An abbreviation used by doctors to mean 'by mouth' when they prescribe medicines. These are medicines you swallow.

PR (per rectum)

An abbreviation used by doctors to mean 'by rectum' when they prescribe medicines. These are medicines that are put in your bum.

Prepayment certificate

If you usually pay for your prescriptions in England and are prescribed more than three medicines a month, it will work out cheaper to get a prepayment certificate from the NHS. You can buy three- or 12-month certificates.


An instruction written by a medical practitioner (usually a doctor) that authorises a patient to be issued with a medicine or treatment. Prescriptions are then taken to a pharmacy to get the medicines dispensed.

PRN (pro re nata)

An abbreviation used by doctors to mean 'when required' when they prescribe medicines.


A medical doctor who is trained in and specialises in the diagnosis and treatment of mental disorders. You may be seen by a psychiatrist at Child and Adolescent Mental Health Services (CAMHS) or Adult Mental Health Services (AMHS).


Q [x]h

Q [x]h is an abbreviation used by doctors to mean ‘every x number of hours’ when they prescribe medicines. The x will be replaced by a number and this is how frequent they want the medicine to be used.

QDS or QID (4x a day)

QDS and QID are abbreviations used by doctors to mean 'four times a day' when they prescribe medicines

QQH (every four hours)

An abbreviation used by doctors to mean 'every four hours' when they prescribe medicines.


Royal College of Psychiatrists (RCP)

The Royal College of Psychiatrists is the main professional organisation of psychiatrists in the United Kingdom. See Psychiatrist.


Second-generation antipsychotic

See atypical antipsychotic.

Selective serotonin reuptake inhibitors (SSRIs)

A type of antidepressant which works on serotonin in the brain. Examples include citalopram and fluoxetine.


Serotonin is a chemical in the brain that helps relay signals from one area of the brain to another. Low levels of serotonin are linked to depression, though the exact relationship is unclear. Also known as 5-HT.

Serotonin syndrome

Serotonin syndrome is a group of symptoms that are associated with too much serotonin in the body. This can occur from a combination of medicines that increase levels of serotonin, e.g. antidepressants, or too much of a medicine that increases levels of serotonin, e.g. overdose.

Serotonin and noradrenaline reuptake inhibitors (SNRIs)

A type of antidepressant which works on two chemicals (serotonin and noradrenaline) in the brain. An example is venlafaxine.

(N.B. Noradrenaline is sometimes known as norepinephrine.)

Short-acting injections

Short-acting injections work quickly and are used by doctors when they need the medication to start working very quickly — like during a crisis episode or hospitalisation. They commonly include lorazepam (a benzodiazepine) and haloperidol (an antipsychotic).


Stimulants can be used as legal substances, prescription medicines or street drugs. Stimulants include caffeine, nicotine, amphetamine and cocaine. On-prescription amphetamines are used for the treatment of ADHD.


The term for when a medicine is mixed into a liquid.

Sustained release

Sustained-release tablets release the active ingredient over an extended period of time, meaning more constant drug levels, fewer side effects and less frequent dosing.


Tardive dyskinesia

This is a side effect of long-term use of typical antipsychotics which results in abnormal muscular movements.

TDS (3x a day)

An abbreviation used by doctors to mean 'three times a day' when they prescribe medicines.

Tricyclic antidepressant

A type of antidepressant used to treat depression. Examples includes lofepramine, imipramine and clomipramine.

Typical antipsychotic

Also known as a first-generation antipsychotic, this is the original or older type of antipsychotic.



When medicines are made, the drug manufacturer applies for a licence that means the medicine has been approved for a specific condition and group of people. Unlicensed medicines are ones that are do not have a licence in the UK. They may be imported from another country where they are licensed, or specially made liquid formulations of a medicine. Unlicensed medicines are only prescribed after careful consideration of other options.


Withdrawal symptoms

Uncomfortable effects that you may experience if you stop a medicine, especially if you stop quickly or suddenly. See also discontinuation symptoms.


Yellow Card system

A system for the public and health professionals to report side effects from medicines.


Z drugs

A class of medicines used to treat insomnia. They should only be used for a short time as they can lead to dependence. Examples include zopiclone and zolpidem. These medicines should be used along with with good sleep hygiene.


NICE provide guidelines on the use of zaleplon, zolpidem and zopiclone for the short-term management of insomnia.


N.B. since publication, zaleplon has been discontinued.