Pharmacodynamics and Pharmacokinetics

Pharmacokinetics

Refers to how the body absorbs, distributes, changes, or eliminates a particular substance.

Onset of action

The time from medication administration until clinical effects occur.

Duration

The length of time that clinical effects persist.

Elimination

How medications or chemicals are removed from the body.

Peak

The point or period when the maximum clinical effect is achieved.

Pharmacokinetics in special conditions

Patients with liver or kidney disease have altered pharmacokinetics compared to healthy individuals.

Pharmacodynamics and pharmacokinetics determine

How quickly a medication begins to work, when its effects will peak, how long it will last, and when additional doses are safe to give.

Factors altering medication effects

Shock states, altered vital signs, and medication interactions can change both pharmacodynamics and pharmacokinetics.

EMS importance

Pharmacokinetic timing is especially important when treating pain with opioids or managing an opioid overdose with naloxone (Narcan).