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Pharmacy & Pharmacology vocabulary · Pharmacodynamics and Drug Action

Onset of action

Meaning in pharmacy & pharmacology, with examples

nounCommon term

In pharmacy & pharmacology, onset of action means: The time between taking a medicine and the moment it starts to have a noticeable effect.

In Turkish: etki başlangıcı, etkinin başlama süresi

How it is used

Usually described as rapid or slow, and often paired with 'duration of action'. It depends on the route and the formulation: an IV drug or a sublingual spray acts within minutes, while a tablet usually takes longer. When patients ask 'How long until it works?', they are asking about the onset of action.

Example sentences

  1. Rapid-acting insulin has a much faster onset of action than long-acting insulin.

  2. Antidepressants have a slow onset of action, so patients may not feel better for a few weeks.

Common collocations

  • rapid onset of action
  • slow onset of action
  • duration of action
  • onset and duration
  • route of administrationThe way a medicine enters the body, for example by mouth, through the skin, by injection into a vein or muscle, or by breathing it in.
  • absorptionThe movement of a drug from the place where it is given, such as the gut or the skin, into the bloodstream.
  • plasma concentrationThe amount of a drug in a given volume of blood plasma at a particular time, used to describe how a drug behaves and to check that levels are safe.
  • antidepressantA medicine used to treat depression and some other conditions, such as anxiety disorders and certain kinds of long-term pain.

More terms: Pharmacodynamics and Drug Action

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This page explains English vocabulary for learners. It is not medical advice.