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High abuse potential, no accepted medical use
LSD and Heroin
High abuse potential, accepted medical use
Less abuse potential than schedule II, moderate dependence liability
Less abuse potential than schedule II drug; limited dependence liability
Less ause potential and very limited dependence
the patients dont know
Double blinded Trial
Both the patients and the doctors dont know who received what
During clinical trials:
- •a relatively small number of patients are given the
•sample size is not fully representative of patients who will actually use the drug.
•patients takes drug for a relatively short time .
Clinical testing Phase I
healthy volunteers, evaluates drug metabolism and determines effects in humans
Clinical testing Phase II and Phase III
patients, evaluates therapeutic utility, dosage range and effectiveness. Manufacturer applies to FDA for a New Drug Application after completing phase III
Clinical testing Phase IV
–drug is released to patients for general use.
New adverse effects are revealed, voluntary reporting of adverse effects
The same generic name is never used for more than one medication.
is this true or Flase
Generic names tell the nurse the chemical ingredients of the drug
True or False
The generic name of the drug will be the same no matter which company produces the drug.
True or False
Generic names are easy to recall and pronounce.
True or False
Generic names often suggest the action of the drug.
True or Flase
Generic names of the same therapeutic class often have a similar suffix making them easier to identify.
True or False
Drugs that share similar characteristics are grouped together as a pharmacologic group or family.
•Unlike FDA approved agents, DSHEA herbal supplements:
–Require no proof of efficacy or safety
–No standardization or quality control
–May stay on market until after harm has occurred
Four Basic Pharmacokinetic Processes
Solubility refers to
the ability of a drug to dissolve and form a solution.
Lipid solubility is essential
•for any drug that must diffuse across the cell membrane because the membrane is partially composed of lipids
•A molecule dissociates into ions when it dissolves in water or other liquids.
- •In dissociating, the molecule gives up or accepts a proton, thus converting some molecules into
- charged particles.
•Ionized drugs are poorly absorbed, because they do not diffuse easily across lipid membranes.
Non-ionized drug molecules
are lipid soluble and easily pass through lipid membranes.
pH partitioning (ion trapping) :
A drug accumulates on the side of a membrane where the pH most favors its ionization
•A drug moves from its site of administration into the venous or lymphatic circulation
–Bypasses GI tract and variability of absorption from other areas
- –Many advantages
- •Rapid onset and control
•Use of large fluid volumes
•Use of irritant medications
•Rapid onset and irreversibility!
–Peripheral versus central administration
–IV push medication (bolus)
Deltoid, Ventrogluteal, Vastus lateralis
–Viscous or irritating medications
–Z track technique
Absorption from stomach or small intestine
–Factors that influence absorption
•Gastric and intestinal pH
•Solubility and stability of drug
•Gastric emptying time/food in gut
•Co-administration of other drugs
Most variable route
–Oral Drug Forms
–Application to skin or mucous membranes
–Sublingual or buccal
–Local versus systemic effects
The fraction of the administered dose that reaches the systemic circulation and produces effects
•Preparations are equal in bioavailability if the drug they contain is absorbed at the same rate and the same extent
The delivery of the drug into any and all body compartments it can penetrate
Factors that influence Distribution
–Regional blood flow and capillary permeability
–Ability of the drug to exit the vascular system
–Ability of drugs to enter the cells
–Volume of distribution
–Degree of plasma protein binding
–Drug reservoirs or storage sites
Blood Brain Barrier
- •Selective mechanism that opposes the passage of most ions and large molecular compounds from the
- blood to the brain tissue.
- •Drugs must be lipid soluble or have a transport system to leave the blood stream and reach a site
- of action within the brain.
Placental Drug Transfer
Membranes of the placenta do NOT constitute an absolute barrier to the passage of drugs
Lipid soluble drugs readily cross the membrane
Plasma Protein Binding
•Drugs circulate in the plasma either bound or unbound to plasma protein, usually albumin.
•Bound drug molecules are pharmacologically inactive and they remain that way until released from the protein.
•By increasing levels of free drug, increased intensity of drug response may lead to possible toxicity.
In addition to plasma protein binding, drugs may be distributed to
•bone, fat, plasma proteins, or other tissues for storage.
Metabolism (also known as biotransformation):
Enzymatically mediated alteration of drug structure. The alteration or changing of a drug to more ionized or water-soluble and less lipid-soluble forms called metabolites.
- Chemical form of a drug that is a product of one or more biochemical metabolic reactions
- involving the parent drug; more ionized
•Hepatic Drug-Metabolizing Enzymes
•Cytochrome P450 system: Causes changes in rate of metabolism of certain drugs requiring changes in dosage
Hepatic First-Pass Phenomenon
•Rapid hepatic inactivation of certain drugs
- •Orally administered drugs are first absorbed through the walls of the small intestine and initially
- travel through the portal vein to the liver, where they undergo metabolism before reaching the systemic circulation.
•This is known as the first-pass phenomenon.
Minimum effective concentration (MEC)
•Plasma drug level below which therapeutic effects will not occur. A drug must be present at a level at or above the MEC.
Plateau (steady state)
which is the evenly distributed concentration of a drug, occurs when the administration rate equals the rate of drug elimination.
- is achieved in approximately four
- •is the time needed for the plasma
- concentration of a drug to be reduced by 50%.
determines dosing interval. Drugs with a short half life need short dosing interval.
- •Drugs with a longer half life can have longer intervals between doses without loss of therapeutic
the highest serum level after administration, must be kept below toxic level.
the lowest serum level after administration, must be kept above MEC.
by continuous infusion, and reducing dosage size and interval can limit
Administration fluctuationsin drug levels.
the initial dose
•is given to achieve plateau more quickly, an initial large dose may be given. Loading doses are used for drugs with long half–lives.
•Plateau is maintained via a smaller dose, known as a maintenance dose, given after a loading dose.
Most of the drug in the body will be eliminated over an interval of approximately
•four half lives (the same interval to reach plateau) .
the largest effect that a drug can produce.
the amount of drug given to elicit an effect
Two drugs can be equally effective but
have different potency.
is the strength of attraction between a drug and its receptor.
•High affinity drugs have a strong attraction for receptor sites. Drugs with high affinity are very potent.
•Drugs with low affinity have to be present in high concentrations to elicit a response.
is the ability of a drug to activate a receptor upon binding.
•Drugs with high intrinsic activity have high maximal efficacy and produce an intense response.
Activate receptors and have high affinity and intrinsic activity
Mimic action of endogenous regulators
Prevent receptor activity and have high affinity but no intrinsic activity
Lack of intrinsic activity prevents receptor activity.
Effect of antagonist is determined by how much agonist is present.
- •Competitive antagonists: Produce receptor
- blockade by competing with agonists.
•Receptor is occupied by whichever agent is higher in concentration.
- An agonist with moderate intrinsic activity.
- Maximal effect is lower than a full agonist.
Can act as agonists (if no full agonist is present) and antagonists (if a full agonist is present)
results from continuous exposure of cell receptors to an agonist.
Hypersensitivity results from
continuous exposure of cell receptors to antagonist
Average effective dose (ED50)
Dose required to produce a defined therapeutic response in 50% of the population.
Patients must be evaluated individually for the proper dosing. Consider patient variables.
Therapeutic index (ED50 : LD50):
Ratio between average effective dose & average lethal dose
Wide therapeutic index is relatively safe.
Narrow therapeutic index is relatively unsafe.
when a patient is taking two drugs, one drug may intensify the effects of the other.
•Increase the therapeutic effect of one of the drugs
•Increase the adverse effects of one of the drug
An inhibitory drug interaction results in the reduced effects of one drug.
•Reduced therapeutic effect
•Reduced adverse effects
Drug- Food interactions
Food and drugs may interact to alter the effect of pharmacotherapy.
- Drug efficacy may be either diminished or enhanced nutritionally by changes in drug absorption, drug
- metabolism, and drug excretion.
Grapefruit juice Effect
Grapefruit juice inhibits an isoenzyme responsible for intestinal metabolism of multiple drugs
This inhibitory effect is dependent on the amount of juice consumed & can persist for up to 3 days
- Increases amount of drug available for absorption
- which increases the blood level of drugs
Patient teaching point
Drug Herb Interactions
Drug interactions may also result from herbal supplements interacting with drugs.
They can have an impact on therapeutic outcome including increased toxicity from herbal supplements and reduced therapeutic outcomes of prescribed agents.
marked by increasing reactivity on subsequent exposures to the foreign agent. It is independent of dosage.
a systemic reaction caused by contraction of smooth muscles and increased vascular permeability.
It is characterized by dyspnea, bronchospasm, laryngeal edema, cardiac dysrhythmias, and occasionally seizures.
- Anaphylaxis is a medical emergency. It is the most
- serious of allergic reactions.
drug response is an unusual, abnormal or peculiar response to a drug.
Sometimes an idiosyncratic response is referred to as a paradoxical response.
- Idiosyncratic responses are thought to occur because of genetic enzymatic deficiencies that alter the drug’s metabolism
a disease produced by drugs.
- For example, some adverse effects of drugs produce symptoms which resemble naturally occurring
- a state in which the body has adapted to prolonged drug exposure in such a way that abstinence
- syndrome will result if drug use is discontinued.
Abstinence syndrome varies depending on drug.
Patient teaching related to abrupt discontinuation
•Ability of certainmedications and environmental chemicals to cause cancer
•Drug induced birth defects
Injury to the CNS is largely irreversible.
Neurotoxicity can occur after exposure to drugs and other chemicals and gases.
The extreme susceptibility of neural tissue to toxicants is largely due to its high metabolic rate, high lipid content, and high circulatory requirement.
Signs and Symptoms of Neurotoxicity
changes in level of consciousness (drowsiness, restlessness)auditory and visual disturbances, nystagmus, and tonic-clonic (grand mal) seizures.
- The liver is highly susceptible to toxicants due to direct exposure to ingested drugs and other
- toxicants. Primary site of drug metabolism.
- Manifestations of hepatotoxicity include hepatitis,
- jaundice, elevated liver enzymes [laboratory values], and fatty infiltration of the liver.
High susceptibility due to high vascularity
Chemically induced kidney damage is typically manifested as acute tubular necrosis.
Laboratory values to assess: Blood urea nitrogen (BUN), creatinine, creatinine clearance
A wide variety of drugs can affect the immune system.
Some may cause immunosuppression (decrease ability to fight infection), whereas others may directly destroy immune system components (i.e. leukocytes)
- Irregularities in cardiac rhythms and conduction and possibly heart damage may result from an
- adverse effect known as cardiotoxicity.
- Cause unknown
- Characteristics of cardiotoxicity include transient
- cardiac arrhythmias and depression of myocardial function.
Many drugs can produce ototoxicity, which affects the eight cranial nerve and result is inner ear or auditory nerve damage.
Structures of the inner ear that may be affected include the cochlea, vestibule and semicircular canals.
Ototoxicity may or may not be reversible.
Body surface area is more precise than
•Percentage of body fat can change drug distribution
decreased responsiveness to a drug as a result of repeated drug administration.
- Patients who are tolerant to a drug require higher doses to produce the same effects that were
- achievable with lower doses before tolerance had developed.
occurs when a minimum effective concentration (MEC) is abnormally high.
This is thought to result from chronic receptor occupation
Results from accelerated drug metabolism brought about by the ability of certain drugs to induce synthesis of hepatic drug-metabolizing enzymes. Dosage must be increased to maintain therapeutic levels
- A form of tolerance where the reduction in drug responsiveness is brought on by repeating dosing
- over a short time (within hours) instead of days to weeks as in pharmacodynamic and metabolic
Pharmacogenetics is the study of genetically inherited conditions that affect the way drugs act on the body and modify the way the body acts on drugs.
•Glucose-6-dehydrogenase deficiency (G6PD): Administration of certain drugs causes hemolytic anemia. Common in African, Middle Eastern, and South Asian peoples.
Err on the side of caution:
Any drug taken during pregnancy will reach the fetus
Physiologic changes during pregnancy can alter pharmacokinetics of drugs
Pregnancy Category A
- Adequate and well-controlled studies
- have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).
Pregnancy Category B
- Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an
- adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in any trimester.
Pregnancy Category C
- Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and
- well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Pregnancy Category D
- There is positive evidence of human
- fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Pregnancy Category X
Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.
Functions of the ANS
–Control of smooth muscle (e.g., bronchi, blood vessels, GI tract)
–Exocrine glands (e.g., gastric, sweat, salivary)
•Monitored by both the sympathetic and parasympathetic nervous systems
The ANS works by
•antagonism between the sympathetic and parasympathetic nervous systems.
•To effect an action, a neurotransmitter needs to bind with an appropriate receptor site on the effector organ or tissue.
This is accomplished by synaptic transmission.
•Involves the synthesis of neurotransmitters in the nerve terminal.
•Includes storage of the neurotransmitter awaiting an action potential.
•Involves release of the specific neurotransmitter.
•After release, the neurotransmitter diffuses across the synaptic gap and reversibly binds to a receptor on the postsynaptic cell.
Synaptic Transmission after binding
•and exerting an effect, the neurotransmitter is dissociated from its binding site by a variety of mechanisms.
•The neurotransmitter is now degraded or “reuptaked” for reuse.
•Preganglionic transmission is mediated by acetylcholine.
•Postganglionic transmission is mediated by NE.
•Adrenal medulla stimulation to release epinephrine is mediated by acetylcholine.
•Alpha-1, alpha-2, beta-1, and beta-2.
•Drugs that stimulate the receptors are called agonists.
•Drugs that block the receptors are called antagonists or blockers.
•Most drugs stimulate or block more than one receptor at a time.
•Some drugs are relatively selective in their stimulation or blockade.
Stimulation of Alpha-1 Receptors
- •Stimulation causes:
- –Increased peripheral resistance
- –Increased blood pressure (BP)
- –Pupil dilation (mydriasis)
- –Closure of the internal sphincter of the bladder
- •Blocking causes the opposite
Stimulation of Alpha-2 Receptors
–Decreased release of NE, reducing sympathetic outflow from brain
•Blocking causes the opposite effects.
Stimulation of Beta-1 Receptors
–Increased myocardial contractility
- •Blocking causes the opposite
Stimulation of Beta-2 Receptors
–Slightly decreased peripheral resistance
–Increased muscle and liver glycolysis
–Increased release of glucagon
–Relaxation of uterine smooth muscle
- •Blocking causes the opposite
•Nonselective adrenergic agonist:
–Stimulates all alpha and beta receptors
•Many therapeutic uses, such as:
•Adverse effects related to stimulation of all receptors are common.
•CNS and cardiac adverse effects are the most common and may be the most serious.
- •Pharmacotherapeutics include:
- –Vascular failure
- –Shock states
Pupil dilation (mydriasis)
•Used to treat hypertension.
•Nonselective beta-2 stimulant.
–Congestive heart failure
–Various types of shock
•Inhaled pharmacotherapeutics include:
•Adverse effects are primarily related to cardiac stimulation.
•Nonspecific beta blocker.
•Used primarily for cardiovascular disorders.
•Adverse effects are due to cardiac and respiratory effects.
•Discontinue slowly to prevent rebound tachycardia leading to angina and possibly myocardial infarction.
Parasympathetic Nervous System (PSNS)
•Acetylcholine is the preganglionic and postganglionic neurotransmitter.
•Concentrated in the heart, smooth muscle, and exocrine glands
•Found in the central nervous system (CNS), the neuromuscular junction, autonomic ganglia, and the adrenal medulla
•Drugs that stimulate the PSNS receptors:
Drugs that block the PSNS receptors:
Excess Cholinergic Effects
•Decreased intraocular pressure
•Mitosis (constriction of pupil)
•Increased bronchial secretions
•Increased GI tone
•Contraction of bladder detrusor muscle
Excess Anticholinergic Effects
•Increased intraocular pressure
•Mydriasis (dilation of pupils)
•Decreased bronchial secretions
•Decreased GI motility with possible constipation
•Decreased BP followed by increased BP
•Tachycardia and, possibly, palpitations
•Drowsiness, confusion, and agitation
•Mad as a hatter
•Blind as a bat
•Red as a beet
•Dry as a bone
–Simple and acute glaucoma
–Preoperative and postoperative elevated intraocular pressure
•Stimulates the CNS
- •Pharmacotherapeutics are limited to preparations to
- assist in smoking cessation.
- •Adverse effects are related to
- its effects on the cardiovascular system and CNS
•Indirect-acting cholinergic drug
•Acts by reversibly inhibiting postsynaptic cholinesterase
- •Used in the treatment of myasthenia gravis to minimize muscle
Most serious adverse effect: cholinergic crisis
•Antidote to cholinergic poisoning
–Preoperatively to dry secretions
–Acute cardiac emergencies
–Topically (homatropine) to treat ophthalmic disorders
–Treatment of motion sickness and diarrhea
Atropine Adverse effects
- •Adverse effects related to loss
- of acetylcholine stimulation on receptors
•Most serious adverse effect: anticholinergic overdose (poisoning)