Pharmacokinetics/dynamics Flashcards
Pharmacokinetics includes (4)
- Absorption
- Distribution
- Metabolism/biotransformation
- Excretion
Variables affecting absorption?
- surface of the tissues.
- skin breakdown, abrasions will cause increased absorption.
- hairy areas, scarring will decrease absorption.
- stomach lining. - Medication form. Is it liquid? Solids?
- Route. IV? SC?
- Circulation.
A med given IV push affects absorption in what way?
It DOESN’T!!!!
There is no absorption via IV push. Skips this step and gets distributed immediately!
Variables affecting distribution?
- Drug’s affinity for lipids, certain body tissue.
- Amt of blood flow to specific organs.
- Plasma/protein binding sites. i.e. albumin/free drug
- situations that alter protein binding.
What situations might alter protein binding?
- decreased levels of albumin (older adults).
Hypoalbuminemia.
May cause toxic level of drug!
What is the first pass effect?
The drug is metabolized by the liver or intestine before entering systemic circulation.
Why can’t nitro be administered po?
First pass effect. There will be no bioavailability after!
First pass effect reduces bioavailability when drugs are administered by what route?
Enteral route. Specifically po.
Which parenteral route of administration has the fastest rate of absorption?
IM
Which parenteral route bypasses absorption?
IV! Goes directly to distribution via the bloodstream.
Which enteral routes avoid the first pass effect?
sublingual and buccal
A drug that produces and action is called an
agonist
A local effect is one that effects only?
One body part or site of application.
A dose of medication where the serum level is high enough to be effective but not so high as to be toxic is called?
therapeutic window
Physiological changes seen is older adults that may interfere with pharmacokinetics?
- decreased CO
- slower metabolism
- lower albumin levels
- decreased peristalsis
- decreased muscle mass
- decreased liver and kidney fxn
When a drug level peaks it is exerting the most effect?
T/F
True
What would be an example of idiosyncratic effect?
Excitability instead of sleepiness with Benadryl
What would be an example of a synergistic effect?
Opioids causing more effect than expected. Ex: morphine + heroin, alcohol and sedatives.
1 + 1 = 3
What would be an example of additive effects of medications?
Regardless of whether two meds are given separately or together they have an additive effect. 1 + 1 = 2
Ex: beta blocker reduces BP by 10, and then giving a CCB which reduces BP by another 10.
How long does is take a med given by IV push to reach peak?
approx. 10 - 15 minutes.
What are the effects of anticholinergics?
Can’t see - PUPILLARY DILATION
Can’t pee - URINARY RETENTION (due to ureter constriction/angiotensin aldosterone)
Can’t spit - DECREASED SECRETIONS
Can’t shit - DECREASED PERISTALSIS
When an infection is developed in the hospital, it’s called
Nosocomial, or hospital acquired.
Idiopathic
Unknown
Secondary
when one dz is caused by something else. Ex: CAD is secondary to diabetes, or HTN is secondary to renal dz.
