Exam 1 - Week 2 Flashcards
Define all parameters and equation for calculation
- Bioavailability
- Half-life
- how many half life to eliminate drug from body? - Clearance
- Volume of distribution
- Elimination constant
- Steady state concentration
- Pharmacokinetics
- • Bioavailability - fraction of UNCHANGED DRUG that reach systemic circulation after administration
• All values are 1 or less.
• F=1 is the higher bioavailability that you can get
• E.g statins (that lower cholesterol) - work in liver - 30% bioavailability
• Determine first pass effect or changes in absorption
•to calculate; Administer drug twice (IV and PO)
• F= AUCoral/AUCiv
• Oral has lower bioavailability - • Time it takes for half of drug to be eliminated out of the body - HALF LIFE ; amount it takes for 50% of drug in plasma to decrease/eliminated - by metabolism or excretion
• T1/2 = 0.693/Ke
- 4 half life’s to eliminate drug - Clearance is the volume of blood from which a
drug is totally removed in a given time (L/hr or ml/min)
- due to metabolism or excretion
- total clears is sum of all clearance methods
- CL = Ke x Vd = 0.693 x Vd / t1/2 - • APPARENT volume of distribution (Vd = dose/Co)
• E.g warfarin - 9L Vd - greater than plasma. Thiopental Vd 140L - very lipophilic and redistributes to fat and brain
• Lead toxicity - high affinity for bone so you now make lead phosphate instead of calcium phosphate
• Liver failure - low albumin (warfarin now free to go into tissues) - Ke = 0.693/ t1/2
- • Peaks and trough level up - equilibrium
• Steady state - equilibruim between what you take it and what goes out
• Steady state concentration - rely on constant. It is average plasma concentration once you reach steady state (balance between intake and output)
• Remember it takes 4 half life’s to get to 94% steady state (CSS) - How to predict the concentration of drug you need to give to get a pharmacological effect (relationship between absorption, distribution and elimination as a function of time)
- changes in blood concentration influence effect of the drug
Define the 2 different compartmentment models and look at the graphs
- Dose - central compartment - elimination (metabolism or excretion).
- Double dose - double tissue concentration where it goes to. **Plasma and tissue drug concentration MAY BE DIFFERENT
- A drug doesn’t necessarily go to all tissues (neostigmine used in myasthenia gravis does not cross the BBB). In places that drug goes- increase plasma conc lead to increased tissue concentration
- First go to tissues (distribution) before elimination (excretion or metabolism)
- Semi log plot vs linear plot?
- One - compartment model (first order)
- in drug distribution, equilibrium so fast that body acts as one compartment
- Drug rapidly equilibrates between plasma and
tissues relative to elimination rate
- Semi-log plot; STRAIGHT LINE - 1 COMPARTMENT
- linear plot; CURVED LINE - Two compartment model - 2 phases (zero order)
- drug takes longer to equilibrate between plasma and tissues
- First go to tissues (distribution) before elimination (excretion or metabolism)
- Semi-log plot - 2 COMPARTMENT - CURVED LINE (distribution and elimination phase/line)
- linear; STRAIGHT LINE
Zero vs first order kinetics
- Constant FRACTION eliminated per hour
- semilog plot is linear
- unsaturated enzymes
- constant AMOUNT eliminated per hour
- semilog is curved
- saturated enzymes
- *give examples
- what is Ke
- First order
• 99% of drugs follow first order
• Rate (conc/time) of decrease in drug conc is directly proportional to amount of drug in the body (conc)
• CONSTANT FRACTION
• Ke - K of elimination (value unique for every drug). Does not depend on the amount of drug given. E.g 10% of Advil dose is eliminated per hour (constant fraction) . 200mg dose - first hour eliminate 20mg, second hour 18mg (10% loss each hour)
• A constant fraction is eliminated becuase ENZYMES ARE NOT SATURATED (phase 1 and phase 2 enzymes - previous lecture)
• Linear graph - curved. Semi-log graph - straight line - ZERO ORDER - alcohol, aspirin (arthritis). **If you use aspirin for headache it is first order
• CONSTANT AMOUNT of drug is eliminated (dont matter how much you take) e.g elimination rate is 10 ug/L/hr no matter the dose
• DRUG CAN ACCUMULATE (you can only eliminate a constant amount)
• Saturation kinetics - SATURATED ENZYMES
• Linear graph; straight line
• Semi-log; curved
Relationship between clearance, half life, volume of distribution and plasma drug concentration
**what is CSS directly proportional to? Inversely proportional to?
- Clearance CL = Ke x Vd = 0.683/half life x Vd
- T1/2 = 0.693/ke
- Vd= Clearance x 0.693 / half life
4. Plasma drug conc = C A = C x Vd A = amount of drug C = plasma conc of drug Vd= volume of distribution
- *Remember
- Css directly proportional to dose, half life,
- Css inversely proportional to Vd, clearance
Predict change in steady state drug concentration if a change occurs in another pharmacokinetics parameter
- Maintenance dose
- IV infusion
- Loading dose
- *why you need loading dose?
- *why you need maintenance dose?
- Css = MD/CL
- Css = Infusion rate/CL
- Css = loading dose x F / Vd
- Constant IV infusion - NO VARIABILITY (no peak and trough). You are giving the drug at steady state
- Do In people who need steady rate (don’t want overdose)
Need loading dose; gets people to steady state immediately
• you then need to give maintenance dose (IV or oral) next to keep them at steady state
More formulas
- Is rate of decrease of drug directly proportional to amount of drug ?
- Fraction eliminated
- Fraction in body
- When do you calculate Css (what graph?)
1. Yes Dc/Dt direct proportion to amount of drug A = C x Vd A = amount of drug C = plasma conc of drug Vd = volume of distribution
- Fraction eliminated = 1- 1/2^n
Where n is number of half lives - Fraction in body = 1/2^n
- Css calculated only in FIRST ORDER KINETIC
- cant do in zero order kinetics (constant amount eliminated)
- What is peak and trough and how does this affect maintenance dose
- give 300mg dose a day (300mg daily vs 100mg 3x daily); is CSS affected? Variability in peak and trough?
- • Trough is lowest veils
• Peak is highest level
• Blue SID - same amount drug taken every day - more variability
• Orange - 3x daily (less variability) but steady state concentration is the same
• As you increase dosing interveal - the bigger the variability between pea and trough
• Give drug more times a day so that peak and trough are closer
Identify 4 types of cellular adaptation to physiologic and pathologic conditions
- Cell shrinkage
- Increase in cell SIZE - lead to enlarged organs
- Increase in cell NUMBER in organ or tissue
- Transformation or replacement of one adult cell type with another
A. Which cells can increase in size but not number?
Ways cell adapts due to stress. If they can’t adapt - lead to cell injury - if can’t recover - cell death (necrosis)
- Atrophy (decrease in size)
- Hypertrophy (increase in size)
- Hyperplasia (increase in number)
- Metaplasia (change/transform/replace cell line )
- *Dysplasia - mix of different cells
- *controlled by complex molecular mechanisms
A. Permanent cells (cardiac, neurons, skeletal) - undergo hypertrophy not hyperplasia because they can’t divide
What are the following
- The capacity of cells to adjusting their structure and functions in response to various physiological and pathological conditions.
- Certain changes that cells undergo when they are unable to adjust/adapt to stress
- 2 types? - Necrosis vs apoptosis
- 2 types of necrosis
- Cell adaptation ; response to stress
- Cell injury; response to adaptation failure
A. Reversible; mild, transient injury so cell bounce back - recover from injury
B. Irreversible; cell may die if it can’t recover - necrosis - A. Necrosis - irreversible cell injury lead to changes produced by enzymatic digestion of dead cellular elements
1) COAGULATION necrosis; KINDEY INFARCT - maintain/preserve the normal architecture of necrotic tissue for several days after cell death
2) LIQUEFACTIVE necrosis; always in BRAIN INFARCT OR ABCESS. No preservation
B. Apoptosis; vital process that eliminates unwanted cells - internally programmed series of events affected by dedicated gene products
Cellular adaptation
1. Atrophy
A. Identify stressor ; physiological vs pathological atrophy
1. Due to decreased workload or endocrine stimulation
2. Nutritional deficiency
- *match the following examples
- loss of innervation (enervation atrophy)
- low estrogen
- muscle atrophy/disuse
- uterine atrophy after pregnancy
- starvation
- aging/senile atrophy
**how does loss of brain substance affect gyri and sulci?
- Physiological atrophy
- decreased estrogen levels in menopause lead to atrophy of endometrium, vaginal epithelium and breast
- uterus decrease in size after pregnancy
- aging (senile atrophy); cell loss in tissue containing permanent cells like heart and brain - Pathological
- disuse
- cerebral atrophy (decreased blood supply)
- decreased nutrients from starvation
- enervation atrophy; skeletal muscle depend on nerve supply
- tissue compression with an enlarging bending tumor go through cell atrophy
**loss of brain substance NARROWS GYRI and WIDENS SULCI
- What is the difference between atrophy and cell death
- What is the mechanism of atrophy (4).
- what enzyme pathway is important to note? - What is the marker for atrophy? (Called what type of atrophy?)
- Increase in what also accompany atrophy?
- cells eat themselves
- Atrophy is Not cell death. It is cell trying to conserve energy so you DECREASE CELL SIZE AND NUMBER
- Breaking down stuff - lead to cell shrinkage
A. Increased catabolic activity
B. Decreased protein synthesis and increase protein degradation C. UBIQUITIN-proteasome pathway - UB LIGASE
D. Increased autophagy (Self Eating) - LIPOFUSCIN GRANULES
- aka BROWN ATROPHY
- undigested lipids are stored as residual bodies (lipofuscin granules) - Increased autophagy vacuoles
- autophagy is when starved cells eat its own components to reduce nutrient demand to match the supply
Identify cellular adaptation
Stressor; increased workload induced by growth factors produced in response to mechanical stress or other stimuli - occurs in tissues incapable of cell division
Identify Physiological vs pathological
- heavy workout (massive biceps)
- hypertension or faulty valves state
- uterus increase size in pregnancy
HYPERTROPHY
- Physiological; increased functional demand or stimulation by hormone or growth factor
- skeletal muscle hypertrophy (heavy workout)
- uterine hypertrophy ( estrogen hormones act on smooth muscle - increase smooth muscle proteins and increase cell size) - Pathologic
- CARDIAC HYPERTROPHY from chronic hemodynamics overload from HYPERTENSON or faulty valve stress
- if left untreated can become maladaptive and lead to - heart failure, arrhythmia and sudden DEATH
Mechanism of hypertrophy
- Actions from what 3 things integrate to activate a complex signal transduction pathway
- Which 2 are more important in cardiac hypertrophy?
- What does signal pathway activate? - work coordinately to increase the synthesis of muscle proteins that are responsible for hypertrophy
- Actions of #3 (3)
- A. Mechanical stretch (increased work load)
B. Agonists ( alpha adrenegic hormones, angiotensin)
C. Growth factors (IGF-1, fibroblast growth factor) - A. Agonist
C. Growth factors - Transcription factors (Myc, Fos, Jun)
- A. Introduction of embryonic/fetal genes - cardiac, alpha actin, ANF - increase mechanical performance and decrease work load
B. Increase synthesis of contractile proteins - increase mechanical performance
C. Increased production of growth factors
Identify the cellular adaptation based on mechanism below
- result of growth factor - driven proliferation of mature cells and in some cases by increased output of new cells from tissue stem cells
HYPERPLASIA
Identify physiological or pathological hyperplasia in the following examples
- increased RBC
- proliferative phas eof endometrial Menstrual cycle
- breast development
- hepatica regeneration
- excess hormone stimulation
- endometrial or prostatic hyperplasia (BPH)
- papillomavirus causing skin warts
- Physiologic hyperplasia
- increased RBC
- proliferative phas eof endometrial Menstrual cycle
- breast development
- hepatica regeneration - Pathological hyperplasia
- excess hormone stimulation
- endometrial or prostatic hyperplasia (BPH)
- papillomavirus causing skin warts
Identify cellular adaptation
- result form chronic irritation
- precede development of cancer in some instances
- arise from reprogramming of stem or undifferentiated cells that are present in adult tissue
**Give examples (2)
METAPLASIA
E.g
1. CILIATED Columnar to squamous cells ( RESPIRATORY TRACT) - in smoking of Vit A deficiency
2. Squamous to columnar (BARRETT ESOPHAGITIS) - gastric acid \, stones in salivary glands, pancreas or bile ducts
Identify 7 causes of cell injury
- Oxygen deprivation; hypoxia, ischemia, hypoxemia, perfusion defects, loss of oxygen carrying capacity of blood (Co poisoning and anemia)
- Physical agents
- Chemical agents and drug reaction
- Infectious agents
- Immunologic reactions (autoimmune)
- Genetic derangement (sickle cell anemia)
- Nutritional imbalances
What are the 4 major targets and biochemical mechanisms of cell injury?
**arrange from immediate occurrence like 1 hr to 10-12 hours)
- Mitochondria and their ATP/ROS under pathologic conditions; no ATP and increased ROS
- Damage to cellular (plasma and lysosomal) membranes ; failure of membrane functional integrity
- Disturbance in calcium homeostasis (entry of calcium)
- Damage to DNA and misfolding of proteins
**Once you damage membrane - IRREVERSIBLE
What nucleus changes are seen during cell death
Necrosis vs Apoptosis
- blebs
- dissolved
- condensed
- fragmented
- Apoptosis
- Apoptotic fragments; BLEBS - Necrosis
A. Pyknosis - Condense (nuclear shrinkage and increased basophilia)
B. Karyorrhexis - Dissolved (breakup/fragment of nucleus that disappear in 2 days)
C. Karyolysis - Fragmented (fading of basophilic chromatin of nucleus)
Identify the various types of necrosis
- conditions of ischemia (coagulated or clotted)
- any INFARCT/ischemia except brain
- bacteria abcess and fungi of any organ
- brain INFARCT (CVA/stroke)
- digestion of tissue by hydrolytic enzymes
- severe trauma not due to lipases
- pancreatic enzymes (lipases)
- chalky white saponification
- occur where fat is present
- immune reactions involving blood vessels
- prominent when complexes of antigen and antibodies are deposited in walls of arteries
- deposition of fibrin like material (smudgy and eosinophilic)
- TUBERCULOSIS and fungi
- chronic inflammation
- lack of oxygen from gangrene and infection
- Coagulative necrosis
- Liquefactive necrosis
- Fat necrosis
- Fibrinogen necrosis
- Caseous necrosis
- Gangrenous necrosis - can cause liquefactive necrosis
Identify type of cell death
- enlarged cell size
- nucleus (pyknosis, karyorrheis, karyolysis)
- disrupted plasma membrane
- enzymatic digestion leakage of cellular content
- frequency inflammatory response
- mainly pathological role
- cell shrinkage
- fragmentation into nucleosome size fragment
- intact plasma membrane
- no leaked - may be released in apoptotic body
- do not provoke inflammation
- often physiological
- Necrosis
- organ damage (whole organ affected) - Apoptosis
- cell damage (individual cell affected)
What is the most common and important cause of acute cell injury underlying human disease ? (2)
Hypoxia and Ischemia
Hypoxia; deficiency of oxygen - cause injury by reducing oxidative respiration (deplete ATP)
Causes of hypoxia; Ischemia (blood loss), cardiorespiratory failure, anemia, CO poisoning (reduced oxygen carrying capacity of blood), severe blood loss
- *cells can adapt - e.g in narrowed artery vessels can shrink in size (atrophy)
- *more sever cell injury lead to injury and cell death
There are 4 biomechanical mechanisms of cellular injury.
List all and describe mitochondrial damage in detail
- MITOCHONDRIAL DAMAGE - ATP low and ROS high.
◦ Ox phos down - ATP low - anaerobic glycolysis UP - excess lactic acid, low glycogen, low pH - clumping of nuclear chromatin
◦ ATP low - low Na pump - efflux of K+ - influx of sodium, calcium and water - cell swell up (REVERSIBLE - fix with oxygen)
- ATP low - detachment of ribosomes - low protein synthesis
◦ ATP low - loss of membrane potential - No ATP - necrosis
- ATP low - cytochrome C - apoptosis
◦ ROS - free radicals; generated in several ways - affect lipids and proteins
◦ Free radicals produced by inflammation, radiation, chemicals, reperfusion injury
◦ Removal of free radicals by antioxidant; SOD (mitochondria), glutathione peroxidase (mitochondria) and catalase (peroxisomes)
- CALCIUM HOMEOSTASIS IMBALANCE
- DNA DAMAGE (misfolded proteins)
- MEMBRANE DAMAGE (plasma and lysosomal membranes)
There are 4 biomechanical mechanisms of cellular injury.
- what contribute to membrane damage?
**Is this reversible?
- ROS; by lipid peroxidation
- Decreased phospholipid synthesis
- Increased phospholipid breakdown (increased action of phospholipase by increased cytosolic calcium)
- Cytoskeleton damage (by protease activation due to increased cytosolic calcium)
**IRREVERSIBLE - cell can’t fix itself ??