Glossary

cross-over study – where patients in a study ‘roll-over’ to a second related study. For example, this can be after a fixed period in a study (ie after 48 weeks) or after another event (for example, not having a treatment response).

fold-change – a term relating to drug resistance after a phenotype resistance test.

4-fold resistance (also called a 4-fold loss in sensitivity) means you need to use four times the dose to get the same reduction in viral load.

arrhythmia is the medical terms for a disturbance of the heart’s natural rhythm.

• tachycardia refers to when the heart beats too fast.
• bradycardia is when the heart beats too slowly.

high level resistance – when an HIV drug no longer works against the virus.

major mutation – a drug resistance mutation that have a big impact on whether a drug continues to work. This used to be called a primary mutation.