Pharmacology Proctored ATI Study Guide

Chapter 1: Pharmacokinetics and Routes of Administration

• Absorption

• Route of admin affects the rate and amount of absorption

• Oral:

• GI pH and emptying time

• Presence of food in the stomach or intestines

• Form of meds (liquid/XR)

• Sublingual/buccal

• Quick absorption systemically through highly vascular mucous membranes

• Inhalation via mouth/nose

• Rapid absorption through alveolar capillary networks

• Intradermal, topical

• Slow, gradual absorption

• SQ/IM

• Highly soluble meds have rapid absorption (10-30min), poorly soluble have slower absorption

• Blood perfusion at site of injection affect absorption

• IV

• Immediate and complete

• Distribution

• Transportation of meds to sites of action by body fluids

• Plasma binding protein: meds compete for protein binding sites within bloodstream, primarily albumin. The

ability of med to bind to protein can affect how much med will leave and travel to target tissues.

• Metabolism

• Primarily occurs in the liver but can take place in the kidney

• Factors that influence metabolism:

• Age (infants/older adults require smaller doses)

• First pass effect: liver inactivates some meds on first pass through and thus require sublingual or IV

route (may need higher dose)

• Excretion:

• Eliminated through the kidneys.

• Kidney dysfunction can result in elevated levels of medications.

• Med Response

• Maintain plasma levels between minimum effective concentration and the toxic concentration:

• Therapeutic index (TI)

• High TI has a wide safety margin.

• Low TI requires monitoring of serum levels.

• Tough levels: obtain immediately before next dose.

• Half-life:

• Time it takes a medication level to drop in the body by 50%.

• Short vs long half-life: long half-life has greater risk for med accumulation in body