Pharmaceutic phase
DISSOLUTION
is the fist phase of drug action
In the pharmaceutic phase the drug becomes a solution so that it can:
Cross the biological membrane
Which form of drug is the most rapidly absorbed from the GI Tract?
Liquid Suspension
Drugs need to be in a solution so that they are absorbed
pharmacokinetics
is the process of drug movement to achieve drug action.
Absorption--> distribution --> metabolism-->and excretion
Protein- based drugs are destroyed by the
small intestine by digestive enzymes
such as insulin and growth hormones
According to your text a drug that is NOT highly protein bound would be:
Freely distributed to the extravascular tissue
The route for drug absorption that has the greatest bioavailability is:
Intravenous
Passive absorption
occurs mostly by diffusion (movement from higher concentration to lower). With the process of diffusion, the drug does not require energy to move across the membrane.
Active absorption
requires a carrier such as an enzyme or protein to move the drug against a concentration gradient. Energy is required.
Pinocytosis
is a process by which cells carry a drug across their membrane by engulfing the dug particles.
drugs that are lipid soluble pass
pass rapidly through GI membranes. The GI membrane is composed mostly of lipid and protein, so drugs pass easily.
Water-soluble drugs need a
Carrier.
either enzyme or protein to pass through the membrane
Large particle pass through a cell membrane if the are
Non ionized (have no positive or negative charge).
*weak acid drugs such as aspirin are less ionized in the stomach, and they pass through the stomach lining easily and rapidly.
Drugs that are lipid soluble and nonionized are absorbed ____ than water-soluble and ionized drugs
FASTER
The process in which the drug passes to the liver first is called
FIRST- PASS EFFECT, or hepatic first pass
Bioavailability
is the subcategory of absorption. It is the percentage of administered drug dose that reaches the systemic circulation.
The serum half-life of a drug is the time required:
After absorption for half of the drug to be eliminated
T.C. has liver and Kidney disease. He is given a medication with a serum half-life of 30 hours. You expect the DURATION OF ACTION of this medication to:
Increase
Free drugs
(drugs not bound to protein) are active and can cause a pharmacologic response. The portion of the drug that is bound is inactive because it is not available to receptors.
As free drug in the circulation decreases, more bound drug is released from the protein to maintain the balance of free drug.
When two highly protien bound drugs are given concurently
they compete for protein-binding sites, thus causing more free drug to be released into the circulation.
Primarily ___ is what protein binding drugs bind to
albumin
For elimination through the Kidneys to be possible, a drug must:
Be Water-Soluble
Creatinine is normally excreted in urine as metabolic waste. However in a renal disorder you would expect the blood creatinine level to be:
Increase
Metabolism
body inactivates or bio transforms drugs. Primary site is the liver. Most drugs are inactivated by liver enzymes and are then converted or transformed by hepatic enzymes to inactive metabolites or water-soluble substances for excretion.
A large % of drugs are lipid soluble; thus the liver metabolizes the lipid-soluble drugs substances to______
water-soluble substance for renal excretion
factors affecting ABSORPTION
- route
- preparation
- dosage
- digestive motility
- digestive enzymes
- blood flow at administration
- lipid solubility
- degree of ionization
- pH of local environment
- drug-drug, drug-food interactions
Cytochrome P450 is a
family of isozymes responsible for the biotransformation of several drugs.
- enzyme induction
- enzyme inhibition
Drug metabolism via the cytochrome P450 system has emerged as an important determinant in the occurrence of several drug interactions that can result in drug toxicities, reduced pharmacological effect, and adverse drug reactions. Recognizing whether the drugs involved act as enzyme substrates, inducers, or inhibitors can prevent clinically significant interactions from occurring.
Prodrugs
converted from inactive form to active
Most drugs are excreted by the kidneys..other routes include?
Kidney = #1
bile, feces, lungs, saliva, sweat, and breast milk
Acidic urine promotes the elimination of _____ & alkaline urine promotes elimination of ______
weak based drugs
weak acid based drugs
Pharmacodynamics
is the study of the way drugs affect the body.
Drug response can cause a primary or secondary physiologic effect or both. The primary is desirable, the secondary effect may be desirable or undesirable.
Dose response =
the relationship between the minimal vs the maximal amount of drug needed to produce the desired affect.
Onset of action
is the time it takes to reach the minimum effective concentration after a drug is administered.
Peak action=
occurs when the drug reaches its highest blood or plasma concentration
Duration of action=
the length of time the drug has a pharmacologic effect
drugs act through receptors by ?
binding to the receptor to produce (INITIATE) a response or to block (PREVENT) a response
The better a drug fits at the receptor site, the more biologically active the drug is.
agonist drugs
drugs that produce a response
antagonist drugs
drugs that block a response
Cholinergic receptors pg.8
are located in the bladder, heart, blood vessels, stomach, bronchi, and eyes.
A drug that stimulates or blocks the cholinergic receptors affects the anatomic sites of location.
Categories of Drug Action
1. stimulation or depression
2. replacement
3. inhibition or killing of organisms
4. irritation
The biological activity of a drug is determined by the:
Fit of the drug at the receptor site
A mechanism of drug action that does not involve a receptor or enzyme such as a cancer drug is:
Nonspecifc
Drugs that attach but do not elicit a response are called:
Antagonists
Knowledge of drug potency does NOT enable us to predict whether a potent drug is more or less toxic. The valid indicator that measures the margin safety of the drug is its:
Therapeutic Index
Drugs with narrow therapeutic ranges such as digoxin (0.5-2 ug/ml), require plasma/serum drug level monitoring _____ to avoid drug toxicity.
At periodic Intervals
After drug administration, the highest plasma/serum concentration of the drug at a specific time is called:
Peak Level
Prior to administration of a medication, the nurse should check a drug reference book to obtain the following pertinent data for:
1. Protein-binding effect
2. Half-Life
3. Therapeutic Range
A time response curve evaluates three parameters of drug action, which does NOT include:
Therapeutic Range
When immediate drug response is desired, a large initial dose is given to rapidly achieve an MEC in the plasma.
Loading Dose
Peak drug levels
indicate the rate of absorption of the drug
highest concentration of a drug
trough drug levels
indicate the rate of elimination of the drug
lowest concentration of a drug
drugs with a high therapeutic index have a
wide margin of safety and less danger of producing toxic effects
Side effects and adverse reaction
are physiologic effects not related to desired drug affects.
Adverse reaction are more severe than side effects.
Tolerance
refers to a decreased responsiveness over the course of therapy.
Absorption, Distribution, Metabolism(biotransformation), Excretion of drugs by the body
Pharmacokinetics
Biochemical and Physical effects of drugs and mechanism of drug actions
Pharmacodynamics
Name given by United States Adopted Name Council
Generic (NONPropietary) Name
Celeste =
Hoe
Lety=
(no comment)
Pregnancy Category A
No risk to fetus
Pregnancy Category B
no risk to animal fetus but information in humans is unavailable
Pregnancy Category C
Adverse effects in animal fetus, in humans is unavailable
Pregnancy Category D
Possible fetal risk in humans reported, however potential benefit may in selected cases may warrant use of drug
Pregnancy Category X
Fetal Abnormalities reported and positive evidence of fetal risk in humans is available from animal/human studies. Never should be taken by pregnant women.
Therapeutic action of drug
Risk Vs. Benefit
Benefits
Side Effects/ Adverse reactions or contraindication
Risk Vs. Benefit
Risk
prevention of disease through vaccine
Prophylactic (Drug Therapy)
Drug bound to protein, cause inactive drug action/response
Protein bound drug
Not bound to protein causing pharmacologic response that is active.
Free Drug
As it decreases, more bound drug is released from protein
Free drug
Time it takes for one half concentration to be eliminated
Half-Life
Drug reaches highest blood/plasma concentration
Peak Action
length of time drug has pharmacologic effect
Duration of Action
Medication given on time.
Given at Correct time.
Lab aware of tests.
Set up blood draw
Responsibilities of Nurse obtaining Peak And Trough
Indicate Time of highest plasma concentration & Rate of absorption.
Peak
Time of lowest plasma concentration & Rate of Elimination
Trough
IV, IO
ET, INHALATION
SL, RECTAL, BUCCAL
IM
SQ
PO
ROUTES of Drug Admin. in ORDER OF RAPID ABSORPTION
"RIGHT" Medication Administration check list
right drug
right dose
right time
right route
right patient
What Nurse listens to from pt as they list symptoms
Subjective Data
What Nurse Observes
Objective Data
Dissolution of the drug
Pharmaceutic
Effect of drug action because of hereditary influence
Pharmacogenetic
4 processes of drug movement to achieve drug action
Pharmacokinetic
Effect of drug action on cells
Pharmacodynamic
Drug that block a response
Antagonist
Drug that produces a response
Agonist
Drug absorbed by diffusion
Passive Absorption
Which type of drug passes rapidly through the GI Membrane?
Lipid-Soluble and nonionized
What Affects a drug absorption?
Hypotension, Pain, Stress
Two drugs given together cancels the effect of each other
Antagonistic Effect
Adrenergic agonist affect the..
sympathetic nervous system
Sympathomimetics affect the ...
sympathetic nervous system
Adrenergic receptors are typically found where in the body?
effector cells of muscles, such as the heart, bronchiole walls, gastrointestinal tract, urinary bladder, and ciliary muscle or the eye.
What does and Alpha ONE receptor do?
increases force of heart contraction; vasoconstriction increases blood pressure; mydriasis (dilation of pupils) occurs; decreases secretion in salivary glands; increases urinary bladder relaxation and urinary sphincter contraction.
What does an Alpha TWO receptor do?
Inhibits release of norepi; dilates blood vessels; produces hypo-tension; decreases gastrointestinal motility and tone.
Beta ONE receptors do?
Increases heart rate and force of contraction; increases renin secretion, which increases blood pressure.
Beta TWO receptors do?
dilates bronchiloes; promotes gastrointestinal and uterine relaxation; promotes increase in blood sugar through glycogenolysis in liver; increases blood flow in skeletal muscles
alpha-adrenergic receptors are located in
blood vessels, eyes, bladder, and prostate
alpha 2 receptors are located in the
the postganglionic sympathetic nerve endings.
Beata 1 receptors are located in the
kidney but primarily the heart
beta 2 receptors are found mostly in the
smooth muscles of the lung and gastrointestinal tract, the liver, and the uterine muscle.
Schedule I
heroin, hallucinogens (LSD, marijuana[except when prescirbed with cancer treatment], mescalin, peyote, psilocybin.)
*high potential for drug abuse not accepted medical use.
Schedule II
*high potential for drug abuse. Accepted medical use. Can lead to strong physical and psychological dependency
ex: demerol, morphine, hydrocodone, methadone, oxycodone
What schedule is cocaine?
schedule II
schedule III
*Medically accepted drugs.Potential abuse is less that that of schedule I and II. May cause dependence.
Schedule IV
*Medically accepted drugs. May cause dependence.
Schedule V
*Medically accepted drugs. Very limited potential for dependence.
(codeine in cough preparations)
What is the nurses role in administering controlled substances?
- account for all controlled drugs
- keep a special controlled-substance record for required information.
- countersign all discarded or wasted medication;wastage must be witnessed.
- ensure that documentation and drugs on hand match.
- keep all controlled drugs in a locked storage area
misfeasance
negligence; giving the wrong drug or drug dose that results in the patient's death.
nonfeasance
omission; omitting a drug dose that results in the patient's death
Malfeasance
giving the correct drug but the wrong route that results in the patient's death
How do you know a generic drug is just as effective?
*it is given an "A" rating
generic drugs have the same active ingredients as brand name drugs but are usually less expensive because manufacturers do not have to do extensive testing; these drugs were clinically tested for safety and efficacy by the pharmaceutic company that first formlated the drug.
Pharmacogenomics
refers to the general study of all the different genes that determine drug behavior.
an enzyme system either induces or inhibits the action of substrates. Induction or inhibition of a substrate accounts for the variations in drug metabolism in individuals and groups.
Cytochrome P-450 enzyme system
Poor metabolizers of antidepressants, antipsychotics, cardiovascular agents, and isoniazid, which can lead to toxicity
people of european descent
Many have diminished therapeutic, effects from beta blockers, ACE inhibitors, and warfarin sodium
People of African descent
drug interaction
as an altered or modified action or effect of a drug as a result of interaction with one or multiple drugs.
Pharmacokinetic interactions
are changes that occur in the absorption, distribution, metabolism or bio-transformation, and excretion of one or more drugs
One drug can block, decrease, or inccrease the absorption of another drug. It can do this by?
- by decreaseing or increasing gasric emptying time
- by changing the gastric pH
- by forming drug complexes
Category I - over the counter drugs
drugs judged to be safe and effective
Category II- OTC
drugs judged to be unsafe or ineffective; these drugs should not be included in nonprescription products
Category III- OTC
drugs for which there is insufficient data to judge safety or efficacy
drug misuse
indiscriminate or recration use of a chemical substance or its use for purposes other than those for which is intended.
drug abuse
drug use inconsistent with medical or social norms
How do you define addiction
a compulsive, uncontrollable craving for and dependence on a substance to such a degree that cessation causes severe reactions
what is tolerance
the need for a larger dose of a drug to obtain the original euphoria.
Decreased effect of a substance that results from repeated exposure. It is possible to develop cross-tolerance to other substances in the same category
what is craving for a drug
subjective need for a substance, usually experienced after decreased use or abstinence. Cue-induced craving is stimulated in the presence of situations previously associated with drug taking.
Withdrawal syndrome
Constellation of physiologic and psychologic responses that occur when there is abrupt cessation or reduced intake of a substance on which an individual is dependent or when the effect is counteracted by a specific antagonist
Metabolism of Alcohol?
- Absorption into the blood stream--> primarily in small intestine-->some in stomach.
- Metabolized by the liver
- Excreted-->Urine --> breath 5%-->sweat (smell drunk)
Alcohol Pharmacology
- CNS depressant
- Affects various neurotransmitter systems
- gaba, glutamate, dopamine, opioid
- enhances the inhibitor effects of GABA on its receptor
Alcohol toxicity ..what happens?
- cant communicate
- irregular/slow heart rate
- hypothermia
- respiratory depression
- coma
- death
*dangerous in combo with other depressants
Physiological effects of Cocaine
- lasts 1-2 hours
- increased energy and motor activity
- increased heat rate and BP
- euphoria
- decreased appetite
- mental alertness
- increased body temp
- dilated pupils
Cocaine toxicity looks like?
- rapid heart beat
- hallucinations
- paranoid delusions
- tremors and convulsions
- respiratory failure
- heart attack or heart failure
- stroke
Physiological effects of Meth
- similar to cocaine
- irritability and aggression
- anxiety and or paranoia/nervousness
- increased wakefulness
- tremors/convulsions
- decreased appetite
- insomnia
- high BP and heart rate
Meth toxicity ?
- neurotoxic : serotonergic neurons and dopaminergic neurons
- Permanent psychosis
- hyperthermia
- kidney failure
- coma
- stroke
- heart attack
Aloe Vera
externally used for treatment of minor burns, insect bites, and sunburns. (fresh is better)
Some success with the treatment of dandruff, oily skin, and psoriasis.
Taken internally, aloe vera is a powerful laxative.
Menstrual flow is increased with small doses.
Garlic: what is it good for?
detoxifies body and increases immune function; decreases platelet aggregation; increases HDL and decreases cholesterol and triglycerides.
Caution: with prescription anticoagulants because of increased fibrinolysis and decreased platelet aggregation
SE: heartburn, flatulence, gastric irritation, decreased RBC, dizziness, diaphoresis
Ginkgo biloba
Antioxidant; peripheral vasodilation and increased blood flow to CNS, reduces platelet aggregation.
Uses: allergic rhinitis, Alzheimer's, anxiety/stress, dementia, vertigo, poor circulation, altitude sickness. Erectile dysfunction.
Role of the nurse when it comes to educating about herbal therapies
- obtain history
- risks vs benefits
- purchase
- storage
- potential interactions
- Do not give to: pregnant or nursing..infants or young children
Pharmacodynamics in the pediatric pt
- differences in body composition
- variability in body water,fat, protein amounts
Pharmacokinetics in the pediatric pt
- immaturity of organs and systems
- greatest effect in newborns and infants
Absorption and the pediatric pt
- reduced gastric acidity
- irregular gastric emptying
- thinner skin- topicals easily absorbed
Distribution in the pediatric pt
- more body water= less drug concentration
Metabolism in the pediatric pt
higher metabolic rates
Excretion in the pediatric pt
immature kidneys
Pharmacokinetics in the geriatric pt (absorption, distribution, metabolism, excretion)
- Absorption: decreased acidity, motility, and blood flow.
- Distribution: decreased protein binding sites and body water. Increased body fat
- Metabolism: decreased liver function
- Excretion: decreased kidney function
Pharmacodynamics in the geriatric pt
- decreased receptors
- decreased affinity
- Altered response to drugs R/T CNS changes
- decreased compensatory response
- higher risk for ADR (?)
- May need lower dose
- may need higher dosing intervals
The geriatric pt and Cardiac glycosides
careful monitoring
the geriatric pt and Anticoagulants
warfarin highly protein bound---> albumin levels are low= high free drug
*close monitoring
The geriatric pt and GI drugs
- Anit-ulcer agents--AVOID TAGAMET
- laxatives
TAGAMET= CAUTION: not good for the older adult..it interacts with every other drug
Are home health aide allowed to give medication?
legally home health aids may only assist with medications the patient customarily self-administers.
What happened to the babies that were born after mom took THALIDOMIDE for morning sickness?
Herbal use and pregnancy
Moms need to be managed on how they can affect the body
Iron and pregnancy
need more RBC= higher blood volume
-dark leafy greens, fortified meats.
-begin in the 2nd trimester
-take on empty stomach
-main issues include constipation, dark stools, nausea.
-Relief: fiber and water
Folic acid and pregnancy (vitamin B9 & folate)
- help prevent against neural tube defects
- should start taking a few months before conseption
- 400-800mcg
- can be found is fortified cereal, broccoli, bread...
What is Tocolytic therapy?
- drug therapy to decrease uterine muscle contraction
- #1 use is calcium antagonist magnesium sulfate
- calcium channel blockers prevent influx of calcium ions, resulting in relaxation of the myometrium
Moral of the story: if you limit the available calcium= interrupt uterine contractions= additional time for fetal maturation & delay delivery