Chapter 1: Pharmacokinetics and Routes of Administration

• Absorption (depends on route)

§ Route of admin affects the rate and amount of absorption

o Oral:

§ GI pH and emptying time

§ Presence of food in the stomach or intestines

§ Form of meds (liquid/XR)

§ Sit upright or put your chin to your chest to aid in swallowing

o Sublingual/buccal

§ Quick absorption systemically through highly vascular mucous

membranes

§ Must make sure it is fully absorbed before you eat or drink

o Inhalation via mouth/nose

§ Rapid absorption through alveolar capillary networks

§ Metered-dose inhaler: shake and press, inhale for 3-5 seconds and

then hold for 10 seconds before exhaling

§ Dry powder: DO NOT SHAKE

o Intradermal, topical

§ Slow, gradual absorption

o SQ/IM

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

soluble have slower absorption

§ Blood perfusion at site of injection affect absorption

o IV

§ Immediate and complete

§ 20 gauge – standard

• Distribution

o Transportation of meds to sites of action by body fluids

o 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

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

o 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

o Eliminated through the kidneys

o Kidney dysfunction can result in elevated levels of medications.

• Med Response