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What is a Black Triangle?

The black triangle is a symbol used in the UK on medicines under intensive safety surveillance for adverse drug reactions (side effects) . Black triangle status normally applies to:

When a newly licensed medicines reach the market, information about adverse effects are limited. This is because although the clinical trials are good at discovering whether the medicine is good at treating the condition it is used for, they only pick up more common side effects. Many important adverse drug reactions are generally rarer than the benefit you obtain from your medicine. In addition, the reporting of adverse drug reactions in trials is highly variable, and often inadaquate.1

So, clinical trials cannot define uncommon, but important, adverse effects of medicines. Mathematically it can be calculated that if you treat n patients with a medicine, and none suffer a particular adverse effect, then the incidence of that adverse reaction will be between 0/n and 3/n.2 New medicines have on average only been used in trials involving 1500 patients.3 This could mean that as many as 1 in 500 patients could suffer a previously unknown adverse effect of a new medicine.

For this reason, effective post marketing surveillance of a new medicine is essential. The presence of a black triangle symbol indicates that suspected reactions, no matter how trivial, associated with these medicines should be reported to the Committee on Safety of Medicines (CSM) via the Yellow Card Scheme. You can read more about black triangle drugs at the MCA here

Does this mean black triangle medicines are dangerous?

No, all drugs that have been authorised by the MCA have undergone evaluation for safety. However, what it does mean is that all the side effects of the medicine may not yet have been found. Occasionally, new medicines may be withdrawn following further safety information which is collected after the medicine has been launched. It must be remembered that new medicines may be safer or more effective than existing medicines.

How do I know if my medicine is a black triangle drug?

A complete list of black triangle drugs is kept here and the symbol may appear on the leaflet you receive with your medicine.

I'm on a black triangle medicine and I think I have a side effect. What do I do?

Speak to your pharmacist, doctor or nurse. They will be able to report the reaction and advise you on how to manage the adverse effect.

1. Ioannidis JPA, Lau JL. Completeness of safety reporting in randomized trials: An evaluation of 7 medical areas. JAMA 2001;285:437-443.

2. Ferner RE. Newly licensed drugs. BMJ 1996;313:1157-8. [text]

3. Rawlins MD. Pharmacovigilance: paradise lost, regained or postponed? J Roy Coll Phys Lond 1995;29(1):41-9.