What determines steady state?

The time to reach steady state is defined by the elimination half-life of the drug. The rule of thumb is that steady state will be achieved after 5 half-lives (97% of steady state achieved). If you have a drug with a long half life, you can achieve a target steady state level more quickly by using a loading dose.

What does steady state concentration mean?

It describes a dynamic equilibrium in which drug concentrations consistently stay within therapeutic limits for long, potentially indefinite, periods. The concentration around which the drug concentration consistently stays is known as the steady-state concentration.

What is an example of steady state?

An example of steady state can be found a bathtub with the drain open and water being added. If water is leaving the tub at the same rate that water is being added, the state variable volume will be constant over time.

Is equilibrium steady state?

The key concept is that any system is most stable at its lowest free energy state under current conditions. When that state is reached the system is at equilibrium. In a steady state, energy is put into the system constantly in order to maintain a higher free energy state than at equilibrium.

What is the importance of steady state concentration?

Understanding steady state is also important for choosing the right dose and dosing interval to achieve a desired steady-state concentration—and for determining how long it will take for therapeutic exposures to be achieved during repeat or continuous dosing, since it might take several doses for a drug to achieve …

What is the maximum safe concentration?

Maximum Safe Concentration (MSC): Also called as minimum toxic concentration (MTC) It is the concentration of drug in plasma above which adverse or unwanted effects are precipitated. Concentration of drug above MSC is said to be in the toxic level.

What is difference between steady state and equilibrium state?

A state of chemical equilibrium is reached when the concentration of reactants and product are constant over time (Wikipedia). In contrast, steady state is when the state variables are constant over time while there is a flow through the system (Wikipedia). …

What is steady state example?

A simple example of such a system is the case of a bathtub with the tap running but with the drain unplugged: after a certain time, the water flows in and out at the same rate, so the water level (the state variable Volume) stabilizes and the system is in a steady state.

What is an example of steady state equilibrium?

A state of chemical equilibrium is reached when the concentration of reactants and product are constant over time (Wikipedia). An example of steady state can be found a bathtub with the drain open and water being added. …

How many half-lives does steady state have?

We call this “steady state.” It takes somewhere between 5 and 6 half-lives for a medication to reach steady state. Thus, medications with short half-lives reach steady state relatively quickly, while those with long half-lives take a long time to reach steady state.

What is minimum safe concentration?

Minimum effective concentration (MEC) is the minimum plasma concentration of a drug needed to achieve sufficient drug concentration at the receptors to produce the desired pharmacologic response, if drug molecules in plasma are in equilibrium with drug molecules in the various tissues (Figure 1.3).