Steady state

Definition

Steady state is the condition in which the overall intake of a drug is in dynamic equilibrium with its elimination. This means the drug's concentration in the bloodstream remains consistent over time with regular dosing.

5 Must Know Facts For Your Next Test

1. The time to reach steady state depends on the drug's half-life and typically takes about 4-5 half-lives.
2. Steady state is crucial for maintaining therapeutic levels of drugs used to treat chronic conditions like Alzheimer’s Disease.
3. Inconsistent dosing can prevent a drug from reaching or maintaining steady state, reducing its efficacy.
4. For Alzheimer’s medications, achieving steady state ensures consistent cognitive benefits and reduces side effects.
5. Steady state concentrations are influenced by factors such as dosage, frequency of administration, and individual patient's metabolism.

Review Questions

• What is steady state and why is it important for chronic medication management?
• How long does it generally take for a drug to reach steady state?
• What factors can influence the achievement of steady state in patients taking Alzheimer’s medications?

Related terms

Half-life: The time required for the concentration of the drug in the blood to reduce by half.

Therapeutic Window:

The range of drug doses that elicits a therapeutic response without causing significant adverse effects.

Bioavailability:

The proportion of a drug that enters the systemic circulation when introduced into the body.