Medicine Information Glossary

Anterograde amnesia

Difficulty forming new memories after taking a medicine. Some sedative medicines can cause this effect.

CNS depression

Reduced activity of the central nervous system. Medicines that cause CNS depression can produce effects such as sleepiness, slowed reactions and reduced alertness. Combining several CNS depressants can increase these effects.

Dependence

A physical or psychological adaptation to regular use of a medicine. Stopping suddenly after dependence has developed can cause withdrawal symptoms.

Half-life

The approximate amount of time it takes for the concentration of a medicine in the body to fall by half.

Half-life is one factor used to understand how long a medicine remains in the body, although it does not necessarily indicate exactly how long a person will feel its effects.

Interaction

An interaction occurs when one medicine, substance or health condition affects how another medicine works.

Interactions can increase side effects, reduce effectiveness or sometimes create serious risks

Insomnia

Difficulty falling asleep, staying asleep or getting sufficient restorative sleep.

Sedation

A reduction in alertness or activity that can range from mild drowsiness to significant sleepiness.

Tolerance

A situation where the body becomes accustomed to a medicine and a particular effect may become less pronounced with continued use.

Withdrawal

Physical or psychological symptoms that can occur when a medicine is reduced or stopped after the body has adapted to regular use.

Rebound symptoms

Symptoms that temporarily return or become worse after stopping a medicine.

For example, someone using a sleeping medicine may experience temporarily worse insomnia after stopping it.

Prescription-only medicine

A medicine that legally requires an appropriate prescription from an authorised prescriber.

Side effect

An unwanted effect that occurs in addition to the intended effect of a medicine.

Side effects can range from mild to serious.

Overdose

Taking more of a medicine than is recommended or prescribed.

An overdose can sometimes cause serious or life-threatening effects and may require urgent medical attention.